struct ssaModule;
struct ssaProcedure;
struct ssaBlock;
struct ssaValue;


struct ssaModule {
	CheckerInfo * info;
	BaseTypeSizes sizes;
	gbArena       arena;
	gbAllocator   allocator;

	String layout;

	Map<ssaValue *> values;  // Key: Entity *
	Map<ssaValue *> members; // Key: String
	gbArray(ssaValue *) nested_type_names; // ssaValue_TypeName
	i32 global_string_index;
};


struct ssaBlock {
	i32 id;
	AstNode *node;
	Scope *scope;
	isize scope_index;
	String label;
	ssaProcedure *parent;

	gbArray(ssaValue *) instrs;
	gbArray(ssaValue *) values;
};

struct ssaTargetList {
	ssaTargetList *prev;
	ssaBlock *     break_;
	ssaBlock *     continue_;
	ssaBlock *     fallthrough_;
};

enum ssaDeferKind {
	ssaDefer_Default,
	ssaDefer_Return,
	ssaDefer_Branch,
};
struct ssaDefer {
	AstNode *stmt;
	isize scope_index;
	ssaBlock *block;
};

struct ssaProcedure {
	ssaProcedure *parent;
	gbArray(ssaProcedure *) children;

	ssaModule *   module;
	String        name;
	Type *        type;
	AstNode *     type_expr;
	AstNode *     body;
	u64           tags;

	isize               scope_index;
	gbArray(ssaDefer)   defer_stmts;
	gbArray(ssaBlock *) blocks;
	ssaBlock *          curr_block;
	ssaTargetList *     target_list;
};

#define SSA_STARTUP_RUNTIME_PROC_NAME "__$startup_runtime"


#define SSA_INSTR_KINDS \
	SSA_INSTR_KIND(Invalid), \
	SSA_INSTR_KIND(Local), \
	SSA_INSTR_KIND(Store), \
	SSA_INSTR_KIND(Load), \
	SSA_INSTR_KIND(GetElementPtr), \
	SSA_INSTR_KIND(ExtractValue), \
	SSA_INSTR_KIND(Conv), \
	SSA_INSTR_KIND(Br), \
	SSA_INSTR_KIND(Ret), \
	SSA_INSTR_KIND(Select), \
	SSA_INSTR_KIND(Unreachable), \
	SSA_INSTR_KIND(BinaryOp), \
	SSA_INSTR_KIND(Call), \
	SSA_INSTR_KIND(MemCopy), \
	SSA_INSTR_KIND(NoOp), \
	SSA_INSTR_KIND(ExtractElement), \
	SSA_INSTR_KIND(InsertElement), \
	SSA_INSTR_KIND(ShuffleVector), \
	SSA_INSTR_KIND(StartupRuntime), \
	SSA_INSTR_KIND(Count),

enum ssaInstrKind {
#define SSA_INSTR_KIND(x) GB_JOIN2(ssaInstr_, x)
	SSA_INSTR_KINDS
#undef SSA_INSTR_KIND
};

String const ssa_instr_strings[] = {
#define SSA_INSTR_KIND(x) {cast(u8 *)#x, gb_size_of(#x)-1}
	SSA_INSTR_KINDS
#undef SSA_INSTR_KIND
};

#define SSA_CONV_KINDS \
	SSA_CONV_KIND(Invalid), \
	SSA_CONV_KIND(trunc), \
	SSA_CONV_KIND(zext), \
	SSA_CONV_KIND(fptrunc), \
	SSA_CONV_KIND(fpext), \
	SSA_CONV_KIND(fptoui), \
	SSA_CONV_KIND(fptosi), \
	SSA_CONV_KIND(uitofp), \
	SSA_CONV_KIND(sitofp), \
	SSA_CONV_KIND(ptrtoint), \
	SSA_CONV_KIND(inttoptr), \
	SSA_CONV_KIND(bitcast), \
	SSA_CONV_KIND(Count)

enum ssaConvKind {
#define SSA_CONV_KIND(x) GB_JOIN2(ssaConv_, x)
	SSA_CONV_KINDS
#undef SSA_CONV_KIND
};

String const ssa_conv_strings[] = {
#define SSA_CONV_KIND(x) {cast(u8 *)#x, gb_size_of(#x)-1}
	SSA_CONV_KINDS
#undef SSA_CONV_KIND
};

struct ssaInstr {
	ssaInstrKind kind;

	ssaBlock *parent;
	Type *type;

	union {
		struct {
			Entity *entity;
			Type *type;
		} Local;
		struct {
			ssaValue *address;
			ssaValue *value;
		} Store;
		struct {
			Type *type;
			ssaValue *address;
		} Load;
		struct {
			ssaValue *address;
			Type *    result_type;
			Type *    elem_type;
			ssaValue *indices[2];
			isize     index_count;
			b32       inbounds;
		} GetElementPtr;
		struct {
			ssaValue *address;
			Type *    result_type;
			Type *    elem_type;
			i32       index;
		} ExtractValue;
		struct {
			ssaConvKind kind;
			ssaValue *value;
			Type *from, *to;
		} Conv;
		struct {
			ssaValue *cond;
			ssaBlock *true_block;
			ssaBlock *false_block;
		} Br;
		struct { ssaValue *value; } Ret;
		struct {} Unreachable;
		struct {
			ssaValue *cond;
			ssaValue *true_value;
			ssaValue *false_value;
		} Select;
		struct {
			Type *type;
			Token op;
			ssaValue *left, *right;
		} BinaryOp;
		struct {
			Type *type; // return type
			ssaValue *value;
			ssaValue **args;
			isize arg_count;
		} Call;
		struct {
			ssaValue *dst, *src;
			ssaValue *len;
			i32 align;
			b32 is_volatile;
		} CopyMemory;

		struct {
			ssaValue *vector;
			ssaValue *index;
		} ExtractElement;
		struct {
			ssaValue *vector;
			ssaValue *elem;
			ssaValue *index;
		} InsertElement;
		struct {
			ssaValue *vector;
			i32 *indices;
			isize index_count;
			Type *type;
		} ShuffleVector;

		struct {} StartupRuntime;
	};
};


enum ssaValueKind {
	ssaValue_Invalid,

	ssaValue_Constant,
	ssaValue_TypeName,
	ssaValue_Global,
	ssaValue_Param,
	ssaValue_GlobalString,

	ssaValue_Proc,
	ssaValue_Block,
	ssaValue_Instr,

	ssaValue_Count,
};

struct ssaValue {
	ssaValueKind kind;
	i32 id;

	union {
		struct {
			Type *     type;
			ExactValue value;
		} Constant;
		struct {
			String name;
			Type *  type;
		} TypeName;
		struct {
			b32 is_constant;
			b32 is_thread_local;
			Entity *  entity;
			Type *    type;
			ssaValue *value;
		} Global;
		struct {
			ssaProcedure *parent;
			Entity *entity;
			Type *  type;
		} Param;
		ssaProcedure Proc;
		ssaBlock     Block;
		ssaInstr     Instr;
	};
};

gb_global ssaValue *v_zero    = NULL;
gb_global ssaValue *v_one     = NULL;
gb_global ssaValue *v_zero32  = NULL;
gb_global ssaValue *v_one32   = NULL;
gb_global ssaValue *v_two32   = NULL;
gb_global ssaValue *v_false   = NULL;
gb_global ssaValue *v_true    = NULL;

struct ssaAddr {
	ssaValue *addr;
	AstNode *expr; // NOTE(bill): Just for testing - probably remove later

	// HACK(bill): Fix how lvalues for vectors work
	b32 is_vector;
	ssaValue *index;
};

ssaAddr ssa_make_addr(ssaValue *addr, AstNode *expr) {
	ssaAddr v = {addr, expr, false, NULL};
	return v;
}

ssaAddr ssa_make_addr_vector(ssaValue *addr, ssaValue *index, AstNode *expr) {
	ssaAddr v = {addr, expr, true, index};
	return v;
}




void ssa_module_init(ssaModule *m, Checker *c) {
	// TODO(bill): Determine a decent size for the arena
	isize token_count = c->parser->total_token_count;
	isize arena_size = 4 * token_count * gb_size_of(ssaValue);
	gb_arena_init_from_allocator(&m->arena, gb_heap_allocator(), arena_size);
	m->allocator = gb_arena_allocator(&m->arena);
	m->info = &c->info;
	m->sizes = c->sizes;

	map_init(&m->values,  m->allocator);
	map_init(&m->members, m->allocator);
	gb_array_init(m->nested_type_names, m->allocator);
}

void ssa_module_destroy(ssaModule *m) {
	map_destroy(&m->values);
	map_destroy(&m->members);
	gb_array_free(m->nested_type_names);
	gb_arena_free(&m->arena);
}

void ssa_module_add_value(ssaModule *m, Entity *e, ssaValue *v) {
	map_set(&m->values, hash_pointer(e), v);
}


Type *ssa_type(ssaValue *value);
void  ssa_set_type(ssaValue *value, Type *type);

Type *ssa_type(ssaInstr *instr) {
	switch (instr->kind) {
	case ssaInstr_Local:
		return instr->Local.type;
	case ssaInstr_Store:
		return ssa_type(instr->Store.address);
	case ssaInstr_Load:
		return instr->Load.type;
	case ssaInstr_GetElementPtr:
		return instr->GetElementPtr.result_type;
	case ssaInstr_ExtractValue:
		return instr->ExtractValue.result_type;
	case ssaInstr_BinaryOp:
		return instr->BinaryOp.type;
	case ssaInstr_Conv:
		return instr->Conv.to;
	case ssaInstr_Select:
		return ssa_type(instr->Select.true_value);
	case ssaInstr_Call: {
		Type *pt = get_base_type(instr->Call.type);
		if (pt != NULL) {
			if (pt->kind == Type_Tuple && pt->Tuple.variable_count == 1)
				return pt->Tuple.variables[0]->type;
			return pt;
		}
		return NULL;
	} break;
	case ssaInstr_MemCopy:
		return t_int;

	case ssaInstr_ExtractElement: {
		Type *vt = ssa_type(instr->ExtractElement.vector);
		Type *bt = base_vector_type(get_base_type(vt));
		GB_ASSERT(!is_type_vector(bt));
		return bt;
	} break;
	case ssaInstr_InsertElement:
		return ssa_type(instr->InsertElement.vector);
	case ssaInstr_ShuffleVector:
		return instr->ShuffleVector.type;
	}
	return NULL;
}

void ssa_set_type(ssaInstr *instr, Type *type) {
	switch (instr->kind) {
	case ssaInstr_Local:
		instr->Local.type = type;
		break;
	case ssaInstr_Store:
		ssa_set_type(instr->Store.value, type);
		break;
	case ssaInstr_Load:
		instr->Load.type = type;
		break;
	case ssaInstr_GetElementPtr:
		instr->GetElementPtr.result_type = type;
		break;
	case ssaInstr_ExtractValue:
		instr->ExtractValue.result_type = type;
		break;
	case ssaInstr_BinaryOp:
		instr->BinaryOp.type = type;
		break;
	case ssaInstr_Conv:
		instr->Conv.to = type;
		break;
	case ssaInstr_Call:
		instr->Call.type = type;
		break;
	}
}

Type *ssa_type(ssaValue *value) {
	switch (value->kind) {
	case ssaValue_Constant:
		return value->Constant.type;
	case ssaValue_TypeName:
		return value->TypeName.type;
	case ssaValue_Global:
		return value->Global.type;
	case ssaValue_Param:
		return value->Param.type;
	case ssaValue_Proc:
		return value->Proc.type;
	case ssaValue_Instr:
		return ssa_type(&value->Instr);
	}
	return NULL;
}


void ssa_set_type(ssaValue *value, Type *type) {
	switch (value->kind) {
	case ssaValue_TypeName:
		value->TypeName.type = type;
		break;
	case ssaValue_Global:
		value->Global.type = type;
		break;
	case ssaValue_Proc:
		value->Proc.type = type;
		break;
	case ssaValue_Constant:
		value->Constant.type = type;
		break;
	case ssaValue_Instr:
		ssa_set_type(&value->Instr, type);
		break;
	}
}



ssaValue *ssa_build_expr(ssaProcedure *proc, AstNode *expr);
ssaValue *ssa_build_single_expr(ssaProcedure *proc, AstNode *expr, TypeAndValue *tv);
ssaAddr   ssa_build_addr(ssaProcedure *proc, AstNode *expr);
ssaValue *ssa_emit_conv(ssaProcedure *proc, ssaValue *value, Type *a_type);
ssaValue *ssa_emit_transmute(ssaProcedure *proc, ssaValue *value, Type *a_type);
void      ssa_build_proc(ssaValue *value, ssaProcedure *parent);




ssaValue *ssa_alloc_value(gbAllocator a, ssaValueKind kind) {
	ssaValue *v = gb_alloc_item(a, ssaValue);
	v->kind = kind;
	return v;
}

ssaValue *ssa_alloc_instr(ssaProcedure *proc, ssaInstrKind kind) {
	ssaValue *v = ssa_alloc_value(proc->module->allocator, ssaValue_Instr);
	v->Instr.kind = kind;
	if (proc->curr_block) {
		gb_array_append(proc->curr_block->values, v);
	}
	return v;
}

ssaValue *ssa_make_value_type_name(gbAllocator a, String name, Type *type) {
	ssaValue *v = ssa_alloc_value(a, ssaValue_TypeName);
	v->TypeName.name = name;
	v->TypeName.type = type;
	return v;
}

ssaValue *ssa_make_value_global(gbAllocator a, Entity *e, ssaValue *value) {
	ssaValue *v = ssa_alloc_value(a, ssaValue_Global);
	v->Global.entity = e;
	v->Global.type = e->type;
	v->Global.value = value;
	return v;
}
ssaValue *ssa_make_value_param(gbAllocator a, ssaProcedure *parent, Entity *e) {
	ssaValue *v = ssa_alloc_value(a, ssaValue_Param);
	v->Param.parent = parent;
	v->Param.entity = e;
	v->Param.type   = e->type;
	return v;
}


ssaValue *ssa_make_instr_local(ssaProcedure *p, Entity *e) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Local);
	ssaInstr *i = &v->Instr;
	i->Local.entity = e;
	i->Local.type = e->type;
	ssa_module_add_value(p->module, e, v);
	return v;
}


ssaValue *ssa_make_instr_store(ssaProcedure *p, ssaValue *address, ssaValue *value) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Store);
	ssaInstr *i = &v->Instr;
	i->Store.address = address;
	i->Store.value = value;
	return v;
}

ssaValue *ssa_make_instr_load(ssaProcedure *p, ssaValue *address) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Load);
	ssaInstr *i = &v->Instr;
	i->Load.address = address;
	i->Load.type = ssa_type(address);
	return v;
}

ssaValue *ssa_make_instr_get_element_ptr(ssaProcedure *p, ssaValue *address,
                                         ssaValue *index0, ssaValue *index1, isize index_count,
                                         b32 inbounds) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_GetElementPtr);
	ssaInstr *i = &v->Instr;
	i->GetElementPtr.address = address;
	i->GetElementPtr.indices[0]   = index0;
	i->GetElementPtr.indices[1]   = index1;
	i->GetElementPtr.index_count  = index_count;
	i->GetElementPtr.elem_type = ssa_type(address);
	i->GetElementPtr.inbounds     = inbounds;
	return v;
}

ssaValue *ssa_make_instr_extract_value(ssaProcedure *p, ssaValue *address, i32 index, Type *result_type) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_ExtractValue);
	ssaInstr *i = &v->Instr;
	i->ExtractValue.address = address;
	i->ExtractValue.index = index;
	i->ExtractValue.result_type = result_type;
	Type *et = ssa_type(address);
	i->ExtractValue.elem_type = et;
	GB_ASSERT(et->kind == Type_Struct || et->kind == Type_Array || et->kind == Type_Tuple);
	return v;
}


ssaValue *ssa_make_instr_binary_op(ssaProcedure *p, Token op, ssaValue *left, ssaValue *right) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_BinaryOp);
	ssaInstr *i = &v->Instr;
	i->BinaryOp.op = op;
	i->BinaryOp.left = left;
	i->BinaryOp.right = right;
	return v;
}

ssaValue *ssa_make_instr_br(ssaProcedure *p, ssaValue *cond, ssaBlock *true_block, ssaBlock *false_block) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Br);
	ssaInstr *i = &v->Instr;
	i->Br.cond = cond;
	i->Br.true_block = true_block;
	i->Br.false_block = false_block;
	return v;
}

ssaValue *ssa_make_instr_unreachable(ssaProcedure *p) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Unreachable);
	return v;
}

ssaValue *ssa_make_instr_ret(ssaProcedure *p, ssaValue *value) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Ret);
	v->Instr.Ret.value = value;
	return v;
}

ssaValue *ssa_make_instr_select(ssaProcedure *p, ssaValue *cond, ssaValue *t, ssaValue *f) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Select);
	v->Instr.Select.cond = cond;
	v->Instr.Select.true_value = t;
	v->Instr.Select.false_value = f;
	return v;
}

ssaValue *ssa_make_instr_call(ssaProcedure *p, ssaValue *value, ssaValue **args, isize arg_count, Type *result_type) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Call);
	v->Instr.Call.value = value;
	v->Instr.Call.args = args;
	v->Instr.Call.arg_count = arg_count;
	v->Instr.Call.type = result_type;
	return v;
}

ssaValue *ssa_make_instr_copy_memory(ssaProcedure *p, ssaValue *dst, ssaValue *src, ssaValue *len, i32 align, b32 is_volatile) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_MemCopy);
	v->Instr.CopyMemory.dst = dst;
	v->Instr.CopyMemory.src = src;
	v->Instr.CopyMemory.len = len;
	v->Instr.CopyMemory.align = align;
	v->Instr.CopyMemory.is_volatile = is_volatile;
	return v;
}

ssaValue *ssa_make_instr_conv(ssaProcedure *p, ssaConvKind kind, ssaValue *value, Type *from, Type *to) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_Conv);
	v->Instr.Conv.kind = kind;
	v->Instr.Conv.value = value;
	v->Instr.Conv.from = from;
	v->Instr.Conv.to = to;
	return v;
}

ssaValue *ssa_make_instr_extract_element(ssaProcedure *p, ssaValue *vector, ssaValue *index) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_ExtractElement);
	v->Instr.ExtractElement.vector = vector;
	v->Instr.ExtractElement.index = index;
	return v;
}

ssaValue *ssa_make_instr_insert_element(ssaProcedure *p, ssaValue *vector, ssaValue *elem, ssaValue *index) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_InsertElement);
	v->Instr.InsertElement.vector = vector;
	v->Instr.InsertElement.elem   = elem;
	v->Instr.InsertElement.index  = index;
	return v;
}

ssaValue *ssa_make_instr_shuffle_vector(ssaProcedure *p, ssaValue *vector, i32 *indices, isize index_count) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_ShuffleVector);
	v->Instr.ShuffleVector.vector      = vector;
	v->Instr.ShuffleVector.indices     = indices;
	v->Instr.ShuffleVector.index_count = index_count;

	Type *vt = get_base_type(ssa_type(vector));
	v->Instr.ShuffleVector.type = make_type_vector(p->module->allocator, vt->Vector.elem, index_count);

	return v;
}

ssaValue *ssa_make_instr_no_op(ssaProcedure *p) {
	ssaValue *v = ssa_alloc_instr(p, ssaInstr_NoOp);
	return v;
}





ssaValue *ssa_make_value_constant(gbAllocator a, Type *type, ExactValue value) {
	ssaValue *v = ssa_alloc_value(a, ssaValue_Constant);
	v->Constant.type  = type;
	v->Constant.value = value;
	return v;
}

ssaValue *ssa_make_value_procedure(gbAllocator a, ssaModule *m, Type *type, AstNode *type_expr, AstNode *body, String name) {
	ssaValue *v = ssa_alloc_value(a, ssaValue_Proc);
	v->Proc.module = m;
	v->Proc.type   = type;
	v->Proc.type_expr = type_expr;
	v->Proc.body   = body;
	v->Proc.name   = name;
	return v;
}

ssaValue *ssa_make_value_block(ssaProcedure *proc, AstNode *node, Scope *scope, String label) {
	ssaValue *v = ssa_alloc_value(proc->module->allocator, ssaValue_Block);
	v->Block.label  = label;
	v->Block.node   = node;
	v->Block.scope  = scope;
	v->Block.parent = proc;

	gb_array_init(v->Block.instrs, gb_heap_allocator());
	gb_array_init(v->Block.values, gb_heap_allocator());

	return v;
}

b32 ssa_is_blank_ident(AstNode *node) {
	if (node->kind == AstNode_Ident) {
		ast_node(i, Ident, node);
		return is_blank_ident(i->token.string);
	}
	return false;
}


ssaInstr *ssa_get_last_instr(ssaBlock *block) {
	if (block != NULL) {
		isize len = 0;
		if (block->instrs != NULL) {
			len = gb_array_count(block->instrs);
		}
		if (len > 0) {
			ssaValue *v = block->instrs[len-1];
			GB_ASSERT(v->kind == ssaValue_Instr);
			return &v->Instr;
		}
	}
	return NULL;

}

b32 ssa_is_instr_terminating(ssaInstr *i) {
	if (i != NULL) {
		switch (i->kind) {
		case ssaInstr_Ret:
		case ssaInstr_Unreachable:
			return true;
		}
	}

	return false;
}

ssaValue *ssa_emit(ssaProcedure *proc, ssaValue *instr) {
	GB_ASSERT(instr->kind == ssaValue_Instr);
	ssaBlock *b = proc->curr_block;
	instr->Instr.parent = b;
	if (b) {
		ssaInstr *i = ssa_get_last_instr(b);
		if (!ssa_is_instr_terminating(i)) {
			gb_array_append(b->instrs, instr);
		}
	}
	return instr;
}
ssaValue *ssa_emit_store(ssaProcedure *p, ssaValue *address, ssaValue *value) {
	return ssa_emit(p, ssa_make_instr_store(p, address, value));
}
ssaValue *ssa_emit_load(ssaProcedure *p, ssaValue *address) {
	return ssa_emit(p, ssa_make_instr_load(p, address));
}
ssaValue *ssa_emit_select(ssaProcedure *p, ssaValue *cond, ssaValue *t, ssaValue *f) {
	return ssa_emit(p, ssa_make_instr_select(p, cond, t, f));
}


ssaValue *ssa_add_local(ssaProcedure *proc, Entity *e) {
	return ssa_emit(proc, ssa_make_instr_local(proc, e));
}

ssaValue *ssa_add_local_for_identifier(ssaProcedure *proc, AstNode *name) {
	Entity **found = map_get(&proc->module->info->definitions, hash_pointer(name));
	if (found) {
		return ssa_add_local(proc, *found);
	}
	return NULL;
}

ssaValue *ssa_add_local_generated(ssaProcedure *proc, Type *type) {
	Entity *entity = make_entity_variable(proc->module->allocator,
	                                      proc->curr_block->scope,
	                                      empty_token,
	                                      type);
	return ssa_emit(proc, ssa_make_instr_local(proc, entity));
}

ssaValue *ssa_add_param(ssaProcedure *proc, Entity *e) {
	ssaValue *v = ssa_make_value_param(proc->module->allocator, proc, e);
	ssaValue *l = ssa_add_local(proc, e);
	ssa_emit_store(proc, l, v);
	return v;
}



Type *ssa_type(ssaAddr lval) {
	if (lval.addr != NULL) {
		return ssa_type(lval.addr);
	}
	return NULL;
}

ssaBlock *ssa__make_block(ssaProcedure *proc, AstNode *node, String label) {
	Scope *scope = NULL;
	if (node != NULL) {
		Scope **found = map_get(&proc->module->info->scopes, hash_pointer(node));
		if (found) {
			scope = *found;
		} else {
			GB_PANIC("Block scope not found for %.*s", LIT(ast_node_strings[node->kind]));
		}
	}

	ssaValue *block = ssa_make_value_block(proc, node, scope, label);
	return &block->Block;
}

ssaBlock *ssa_add_block(ssaProcedure *proc, AstNode *node, String label) {
	ssaBlock *block = ssa__make_block(proc, node, label);
	gb_array_append(proc->blocks, block);
	return block;
}

void ssa_build_stmt(ssaProcedure *proc, AstNode *s);
void ssa_emit_no_op(ssaProcedure *proc);
void ssa_emit_jump(ssaProcedure *proc, ssaBlock *block);

void ssa_build_defer_stmt(ssaProcedure *proc, ssaDefer d) {
	ssaBlock *b = ssa__make_block(proc, NULL, make_string("defer"));
	// HACK(bill): The prev block may defer injection before it's terminator
	ssaInstr *last_instr = ssa_get_last_instr(proc->curr_block);
	if (last_instr == NULL || !ssa_is_instr_terminating(last_instr)) {
		ssa_emit_jump(proc, b);
	}
	gb_array_append(proc->blocks, b);
	proc->curr_block = b;
	ssa_build_stmt(proc, d.stmt);
}

void ssa_emit_defer_stmts(ssaProcedure *proc, ssaDeferKind kind, ssaBlock *block) {
	isize count = gb_array_count(proc->defer_stmts);
	isize i = count;
	while (i --> 0) {
		ssaDefer d = proc->defer_stmts[i];
		if (kind == ssaDefer_Return) {
				ssa_build_defer_stmt(proc, d);
		} else if (kind == ssaDefer_Default) {
			if (proc->scope_index == d.scope_index &&
			    d.scope_index > 1) {
				ssa_build_defer_stmt(proc, d);
				gb_array_pop(proc->defer_stmts);
				continue;
			} else {
				break;
			}
		} else if (kind == ssaDefer_Branch) {
			GB_ASSERT(block != NULL);
			isize lower_limit = block->scope_index+1;
			if (lower_limit < d.scope_index) {
				ssa_build_defer_stmt(proc, d);
			}
		}
	}
}




void ssa_emit_unreachable(ssaProcedure *proc) {
	ssa_emit(proc, ssa_make_instr_unreachable(proc));
}

void ssa_emit_ret(ssaProcedure *proc, ssaValue *v) {
	ssa_emit_defer_stmts(proc, ssaDefer_Return, NULL);
	ssa_emit(proc, ssa_make_instr_ret(proc, v));
}

void ssa_emit_jump(ssaProcedure *proc, ssaBlock *block) {
	ssa_emit(proc, ssa_make_instr_br(proc, NULL, block, NULL));
	proc->curr_block = NULL;
}

void ssa_emit_if(ssaProcedure *proc, ssaValue *cond, ssaBlock *true_block, ssaBlock *false_block) {
	ssaValue *br = ssa_make_instr_br(proc, cond, true_block, false_block);
	ssa_emit(proc, br);
	proc->curr_block = NULL;
}

void ssa_emit_no_op(ssaProcedure *proc) {
	ssa_emit(proc, ssa_make_instr_no_op(proc));
}



ssaValue *ssa_lvalue_store(ssaProcedure *proc, ssaAddr lval, ssaValue *value) {
	if (lval.addr != NULL) {
		if (lval.is_vector) {
			// HACK(bill): Fix how lvalues for vectors work
			ssaValue *v = ssa_emit_load(proc, lval.addr);
			Type *elem_type = get_base_type(ssa_type(v))->Vector.elem;
			ssaValue *elem = ssa_emit_conv(proc, value, elem_type);
			ssaValue *out = ssa_emit(proc, ssa_make_instr_insert_element(proc, v, elem, lval.index));
			return ssa_emit_store(proc, lval.addr, out);
		} else {
			value = ssa_emit_conv(proc, value, ssa_type(lval));
			return ssa_emit_store(proc, lval.addr, value);
		}
	}
	return NULL;
}
ssaValue *ssa_lvalue_load(ssaProcedure *proc, ssaAddr lval) {
	if (lval.addr != NULL) {
		if (lval.is_vector) {
			// HACK(bill): Fix how lvalues for vectors work
			ssaValue *v = ssa_emit_load(proc, lval.addr);
			return ssa_emit(proc, ssa_make_instr_extract_element(proc, v, lval.index));
		}
		return ssa_emit_load(proc, lval.addr);
	}
	GB_PANIC("Illegal lvalue load");
	return NULL;
}








void ssa_begin_procedure_body(ssaProcedure *proc) {
	gb_array_init(proc->blocks, gb_heap_allocator());
	gb_array_init(proc->defer_stmts, gb_heap_allocator());
	proc->curr_block = ssa_add_block(proc, proc->type_expr, make_string("entry"));

	if (proc->type->Proc.params != NULL) {
		auto *params = &proc->type->Proc.params->Tuple;
		for (isize i = 0; i < params->variable_count; i++) {
			Entity *e = params->variables[i];
			ssa_add_param(proc, e);
		}
	}
}

void ssa_end_procedure_body(ssaProcedure *proc) {
	if (proc->type->Proc.result_count == 0) {
		ssa_emit_ret(proc, NULL);
	}


// Number blocks and registers
	i32 reg_id = 0;
	gb_for_array(i, proc->blocks) {
		ssaBlock *b = proc->blocks[i];
		b->id = i;
		gb_for_array(j, b->instrs) {
			ssaValue *value = b->instrs[j];
			GB_ASSERT(value->kind == ssaValue_Instr);
			ssaInstr *instr = &value->Instr;
			// NOTE(bill): Ignore non-returning instructions
			switch (instr->kind) {
			case ssaInstr_Store:
			case ssaInstr_Br:
			case ssaInstr_Ret:
			case ssaInstr_Unreachable:
			case ssaInstr_MemCopy:
			case ssaInstr_StartupRuntime:
				continue;
			case ssaInstr_Call:
				if (instr->Call.type == NULL) {
					continue;
				}
				break;
			}
			value->id = reg_id;
			reg_id++;
		}
	}
}

void ssa_push_target_list(ssaProcedure *proc, ssaBlock *break_, ssaBlock *continue_, ssaBlock *fallthrough_) {
	ssaTargetList *tl = gb_alloc_item(proc->module->allocator, ssaTargetList);
	tl->prev          = proc->target_list;
	tl->break_        = break_;
	tl->continue_     = continue_;
	tl->fallthrough_  = fallthrough_;
	proc->target_list = tl;
}

void ssa_pop_target_list(ssaProcedure *proc) {
	proc->target_list = proc->target_list->prev;
}



ssaValue *ssa_emit_arith(ssaProcedure *proc, Token op, ssaValue *left, ssaValue *right, Type *type) {
	switch (op.kind) {
	case Token_AndNot: {
		// NOTE(bill): x &~ y == x & (~y) == x & (y ~ -1)
		// NOTE(bill): "not" `x` == `x` "xor" `-1`
		ssaValue *neg = ssa_make_value_constant(proc->module->allocator, type, make_exact_value_integer(-1));
		op.kind = Token_Xor;
		right = ssa_emit_arith(proc, op, right, neg, type);
		ssa_set_type(right, type);
		op.kind = Token_And;
	} /* fallthrough */
	case Token_Add:
	case Token_Sub:
	case Token_Mul:
	case Token_Quo:
	case Token_Mod:
	case Token_And:
	case Token_Or:
	case Token_Xor:
		left  = ssa_emit_conv(proc, left, type);
		right = ssa_emit_conv(proc, right, type);
		break;
	}

	ssaValue *v = ssa_emit(proc, ssa_make_instr_binary_op(proc, op, left, right));
	ssa_set_type(v, type);
	return v;
}

ssaValue *ssa_emit_comp(ssaProcedure *proc, Token op, ssaValue *left, ssaValue *right) {
	Type *a = get_base_type(ssa_type(left));
	Type *b = get_base_type(ssa_type(right));

	if (are_types_identical(a, b)) {
		// NOTE(bill): No need for a conversion
	} else if (left->kind == ssaValue_Constant) {
		left = ssa_emit_conv(proc, left, ssa_type(right));
	} else if (right->kind == ssaValue_Constant) {
		right = ssa_emit_conv(proc, right, ssa_type(left));
	}

	ssaValue *v = ssa_make_instr_binary_op(proc, op, left, right);
	Type *result = t_bool;
	if (is_type_vector(a)) {
		result = make_type_vector(proc->module->allocator, t_bool, a->Vector.count);
	}
	ssa_set_type(v, result);
	return ssa_emit(proc, v);
}

ssaValue *ssa_emit_ptr_offset(ssaProcedure *proc, ssaValue *ptr, ssaValue *offset) {
	Type *type = ssa_type(ptr);
	ssaValue *gep = NULL;
	offset = ssa_emit_conv(proc, offset, t_int);
	gep = ssa_make_instr_get_element_ptr(proc, ptr, offset, NULL, 1, false);
	gep->Instr.GetElementPtr.elem_type = type_deref(type);
	gep->Instr.GetElementPtr.result_type  = type;
	return ssa_emit(proc, gep);
}

ssaValue *ssa_emit_zero_gep(ssaProcedure *proc, ssaValue *s) {
	ssaValue *gep = NULL;
	// NOTE(bill): For some weird legacy reason in LLVM, structure elements must be accessed as an i32
	gep = ssa_make_instr_get_element_ptr(proc, s, NULL, NULL, 0, true);
	gep->Instr.GetElementPtr.elem_type = ssa_type(s);
	gep->Instr.GetElementPtr.result_type = ssa_type(s);
	return ssa_emit(proc, gep);
}

ssaValue *ssa_emit_struct_gep(ssaProcedure *proc, ssaValue *s, ssaValue *index, Type *result_type) {
	ssaValue *gep = NULL;
	// NOTE(bill): For some weird legacy reason in LLVM, structure elements must be accessed as an i32
	index = ssa_emit_conv(proc, index, t_i32);
	gep = ssa_make_instr_get_element_ptr(proc, s, v_zero, index, 2, true);
	gep->Instr.GetElementPtr.elem_type = ssa_type(s);
	gep->Instr.GetElementPtr.result_type = result_type;

	return ssa_emit(proc, gep);
}

ssaValue *ssa_emit_struct_gep(ssaProcedure *proc, ssaValue *s, i32 index, Type *result_type) {
	ssaValue *i = ssa_make_value_constant(proc->module->allocator, t_i32, make_exact_value_integer(index));
	return ssa_emit_struct_gep(proc, s, i, result_type);
}


ssaValue *ssa_emit_struct_ev(ssaProcedure *proc, ssaValue *s, i32 index, Type *result_type) {
	// NOTE(bill): For some weird legacy reason in LLVM, structure elements must be accessed as an i32
	return ssa_emit(proc, ssa_make_instr_extract_value(proc, s, index, result_type));
}



ssaValue *ssa_array_elem(ssaProcedure *proc, ssaValue *array) {
	Type *t = ssa_type(array);
	GB_ASSERT(t->kind == Type_Array);
	Type *base_type = t->Array.elem;
	ssaValue *elem = ssa_make_instr_get_element_ptr(proc, array, v_zero, v_zero, 2, true);
	Type *result_type = make_type_pointer(proc->module->allocator, base_type);
	elem->Instr.GetElementPtr.elem_type = t;
	elem->Instr.GetElementPtr.result_type = result_type;
	return ssa_emit(proc, elem);
}
ssaValue *ssa_array_len(ssaProcedure *proc, ssaValue *array) {
	Type *t = ssa_type(array);
	GB_ASSERT(t->kind == Type_Array);
	return ssa_make_value_constant(proc->module->allocator, t_int, make_exact_value_integer(t->Array.count));
}
ssaValue *ssa_array_cap(ssaProcedure *proc, ssaValue *array) {
	return ssa_array_len(proc, array);
}

ssaValue *ssa_slice_elem(ssaProcedure *proc, ssaValue *slice) {
	Type *t = ssa_type(slice);
	GB_ASSERT(t->kind == Type_Slice);

	Type *result_type = make_type_pointer(proc->module->allocator, t->Slice.elem);
	return ssa_emit_load(proc, ssa_emit_struct_gep(proc, slice, v_zero32, result_type));
}
ssaValue *ssa_slice_len(ssaProcedure *proc, ssaValue *slice) {
	Type *t = ssa_type(slice);
	GB_ASSERT(t->kind == Type_Slice);
	return ssa_emit_load(proc, ssa_emit_struct_gep(proc, slice, v_one32, t_int));
}
ssaValue *ssa_slice_cap(ssaProcedure *proc, ssaValue *slice) {
	Type *t = ssa_type(slice);
	GB_ASSERT(t->kind == Type_Slice);
	return ssa_emit_load(proc, ssa_emit_struct_gep(proc, slice, v_two32, t_int));
}

ssaValue *ssa_string_elem(ssaProcedure *proc, ssaValue *string) {
	Type *t = ssa_type(string);
	GB_ASSERT(t->kind == Type_Basic && t->Basic.kind == Basic_string);
	Type *base_type = t_u8;
	ssaValue *elem = ssa_make_instr_get_element_ptr(proc, string, v_zero, v_zero32, 2, true);
	Type *result_type = make_type_pointer(proc->module->allocator, base_type);
	elem->Instr.GetElementPtr.elem_type = t;
	elem->Instr.GetElementPtr.result_type = result_type;
	return ssa_emit_load(proc, ssa_emit(proc, elem));
}
ssaValue *ssa_string_len(ssaProcedure *proc, ssaValue *string) {
	Type *t = ssa_type(string);
	GB_ASSERT(t->kind == Type_Basic && t->Basic.kind == Basic_string);
	return ssa_emit_load(proc, ssa_emit_struct_gep(proc, string, v_one32, t_int));
}



ssaValue *ssa_emit_slice(ssaProcedure *proc, Type *slice_type, ssaValue *base, ssaValue *low, ssaValue *high, ssaValue *max) {
	// TODO(bill): array bounds checking for slice creation
	// TODO(bill): check that low < high <= max
	gbAllocator a = proc->module->allocator;
	Type *base_type = get_base_type(ssa_type(base));

	if (low == NULL) {
		low = v_zero;
	}
	if (high == NULL) {
		switch (base_type->kind) {
		case Type_Array:   high = ssa_array_len(proc, base); break;
		case Type_Slice:   high = ssa_slice_len(proc, base); break;
		case Type_Pointer: high = v_one;                     break;
		}
	}
	if (max == NULL) {
		switch (base_type->kind) {
		case Type_Array:   max = ssa_array_cap(proc, base); break;
		case Type_Slice:   max = ssa_slice_cap(proc, base); break;
		case Type_Pointer: max = high;                      break;
		}
	}
	GB_ASSERT(max != NULL);

	Token op_sub = {Token_Sub};
	ssaValue *len = ssa_emit_arith(proc, op_sub, high, low, t_int);
	ssaValue *cap = ssa_emit_arith(proc, op_sub, max,  low, t_int);

	ssaValue *elem = NULL;
	switch (base_type->kind) {
	case Type_Array:   elem = ssa_array_elem(proc, base); break;
	case Type_Slice:   elem = ssa_slice_elem(proc, base); break;
	case Type_Pointer: elem = ssa_emit_load(proc, base);  break;
	}

	elem = ssa_emit_ptr_offset(proc, elem, low);

	ssaValue *slice = ssa_add_local_generated(proc, slice_type);

	ssaValue *gep = NULL;
	gep = ssa_emit_struct_gep(proc, slice, v_zero32, ssa_type(elem));
	ssa_emit_store(proc, gep, elem);

	gep = ssa_emit_struct_gep(proc, slice, v_one32, t_int);
	ssa_emit_store(proc, gep, len);

	gep = ssa_emit_struct_gep(proc, slice, v_two32, t_int);
	ssa_emit_store(proc, gep, cap);

	return slice;
}

ssaValue *ssa_emit_substring(ssaProcedure *proc, ssaValue *base, ssaValue *low, ssaValue *high) {
	Type *bt = get_base_type(ssa_type(base));
	GB_ASSERT(bt == t_string);
	if (low == NULL) {
		low = v_zero;
	}
	if (high == NULL) {
		high = ssa_string_len(proc, base);
	}

	Token op_sub = {Token_Sub};
	ssaValue *elem, *len;
	len = ssa_emit_arith(proc, op_sub, high, low, t_int);

	elem = ssa_string_elem(proc, base);
	elem = ssa_emit_ptr_offset(proc, elem, low);

	ssaValue *str, *gep;
	str = ssa_add_local_generated(proc, t_string);
	gep = ssa_emit_struct_gep(proc, str, v_zero32, ssa_type(elem));
	ssa_emit_store(proc, gep, elem);

	gep = ssa_emit_struct_gep(proc, str, v_one32, t_int);
	ssa_emit_store(proc, gep, len);

	return str;
}


ssaValue *ssa_add_global_string_array(ssaProcedure *proc, ExactValue value) {
	GB_ASSERT(value.kind == ExactValue_String);
	gbAllocator a = gb_heap_allocator();

	isize max_len = 4+8+1;
	u8 *str = cast(u8 *)gb_alloc_array(a, u8, max_len);
	isize len = gb_snprintf(cast(char *)str, max_len, ".str%x", proc->module->global_string_index);
	proc->module->global_string_index++;

	String name = make_string(str, len-1);
	Token token = {Token_String};
	token.string = name;
	Type *type = make_type_array(a, t_u8, value.value_string.len);
	Entity *entity = make_entity_constant(a, NULL, token, type, value);
	ssaValue *g = ssa_make_value_global(a, entity, ssa_make_value_constant(a, type, value));

	map_set(&proc->module->values, hash_pointer(entity), g);
	map_set(&proc->module->members, hash_string(name), g);

	return g;
}

ssaValue *ssa_emit_string(ssaProcedure *proc, ssaValue *elem, ssaValue *len) {
	Type *t_u8_ptr = ssa_type(elem);
	GB_ASSERT(t_u8_ptr->kind == Type_Pointer);

	GB_ASSERT(is_type_u8(t_u8_ptr->Pointer.elem));

	ssaValue *str = ssa_add_local_generated(proc, t_string);
	ssaValue *str_elem = ssa_emit_struct_gep(proc, str, v_zero32, t_u8_ptr);
	ssaValue *str_len = ssa_emit_struct_gep(proc, str, v_one32, t_int);
	ssa_emit_store(proc, str_elem, elem);
	ssa_emit_store(proc, str_len, len);
	return str;
}




ssaValue *ssa_emit_conv(ssaProcedure *proc, ssaValue *value, Type *t) {
	Type *src_type = ssa_type(value);
	if (are_types_identical(t, src_type)) {
		return value;
	}


	Type *src = get_enum_base_type(get_base_type(src_type));
	Type *dst = get_enum_base_type(get_base_type(t));
	if (are_types_identical(src, dst)) {
		return value;
	}

	if (value->kind == ssaValue_Constant) {
		if (dst->kind == Type_Basic) {
			ExactValue ev = value->Constant.value;
			if (is_type_float(dst)) {
				ev = exact_value_to_float(ev);
			} else if (is_type_string(dst)) {
				//
			} else if (is_type_integer(dst)) {
				ev = exact_value_to_integer(ev);
			} else if (is_type_pointer(dst)) {
				// IMPORTANT NOTE(bill): LLVM doesn't support pointer constants expect `null`
				ssaValue *i = ssa_make_value_constant(proc->module->allocator, t_uint, ev);
				return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_inttoptr, i, t_uint, dst));
			}
			return ssa_make_value_constant(proc->module->allocator, t, ev);
		}
	}

	// integer -> integer
	if (is_type_integer(src) && is_type_integer(dst)) {
		GB_ASSERT(src->kind == Type_Basic &&
		          dst->kind == Type_Basic);
		i64 sz = type_size_of(proc->module->sizes, proc->module->allocator, src);
		i64 dz = type_size_of(proc->module->sizes, proc->module->allocator, dst);
		if (sz == dz) {
			// NOTE(bill): In LLVM, all integers are signed and rely upon 2's compliment
			return value;
		}

		ssaConvKind kind = ssaConv_trunc;
		if (dz >= sz) {
			kind = ssaConv_zext;
		}
		return ssa_emit(proc, ssa_make_instr_conv(proc, kind, value, src, dst));
	}

	// boolean -> integer
	if (is_type_boolean(src) && is_type_integer(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_zext, value, src, dst));
	}

	// integer -> boolean
	if (is_type_integer(src) && is_type_boolean(dst)) {
		Token op = {Token_NotEq};
		return ssa_emit_comp(proc, op, value, v_zero);
	}


	// float -> float
	if (is_type_float(src) && is_type_float(dst)) {
		i64 sz = basic_type_sizes[src->Basic.kind];
		i64 dz = basic_type_sizes[dst->Basic.kind];
		ssaConvKind kind = ssaConv_fptrunc;
		if (dz >= sz) {
			kind = ssaConv_fpext;
		}
		return ssa_emit(proc, ssa_make_instr_conv(proc, kind, value, src, dst));
	}

	// float <-> integer
	if (is_type_float(src) && is_type_integer(dst)) {
		ssaConvKind kind = ssaConv_fptosi;
		if (is_type_unsigned(dst)) {
			kind = ssaConv_fptoui;
		}
		return ssa_emit(proc, ssa_make_instr_conv(proc, kind, value, src, dst));
	}
	if (is_type_integer(src) && is_type_float(dst)) {
		ssaConvKind kind = ssaConv_sitofp;
		if (is_type_unsigned(src)) {
			kind = ssaConv_uitofp;
		}
		return ssa_emit(proc, ssa_make_instr_conv(proc, kind, value, src, dst));
	}

	// Pointer <-> int
	if (is_type_pointer(src) && is_type_int_or_uint(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_ptrtoint, value, src, dst));
	}
	if (is_type_int_or_uint(src) && is_type_pointer(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_inttoptr, value, src, dst));
	}

	// Pointer <-> Pointer
	if (is_type_pointer(src) && is_type_pointer(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_bitcast, value, src, dst));
	}

	// proc <-> proc
	if (is_type_proc(src) && is_type_proc(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_bitcast, value, src, dst));
	}

	// pointer -> proc
	if (is_type_pointer(src) && is_type_proc(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_bitcast, value, src, dst));
	}
	// proc -> pointer
	if (is_type_proc(src) && is_type_pointer(dst)) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_bitcast, value, src, dst));
	}



	// []byte/[]u8 <-> string
	if (is_type_u8_slice(src) && is_type_string(dst)) {
		ssaValue *slice = ssa_add_local_generated(proc, src);
		ssa_emit_store(proc, slice, value);
		ssaValue *elem = ssa_slice_elem(proc, slice);
		ssaValue *len  = ssa_slice_len(proc, slice);
		return ssa_emit_load(proc, ssa_emit_string(proc, elem, len));
	}
	if (is_type_string(src) && is_type_u8_slice(dst)) {
		ssaValue *str = ssa_add_local_generated(proc, src);
		ssa_emit_store(proc, str, value);
		ssaValue *elem = ssa_string_elem(proc, str);
		ssaValue *elem_ptr = ssa_add_local_generated(proc, ssa_type(elem));
		ssa_emit_store(proc, elem_ptr, elem);

		ssaValue *len  = ssa_string_len(proc, str);
		ssaValue *slice = ssa_emit_slice(proc, dst, elem_ptr, v_zero, len, len);
		return ssa_emit_load(proc, slice);
	}

	if (is_type_vector(dst)) {
		Type *dst_elem = dst->Vector.elem;
		value = ssa_emit_conv(proc, value, dst_elem);
		ssaValue *v = ssa_add_local_generated(proc, t);
		v = ssa_emit_load(proc, v);
		v = ssa_emit(proc, ssa_make_instr_insert_element(proc, v, value, v_zero32));
		// NOTE(bill): Broadcast lowest value to all values
		isize index_count = dst->Vector.count;
		i32 *indices = gb_alloc_array(proc->module->allocator, i32, index_count);
		for (isize i = 0; i < index_count; i++) {
			indices[i] = 0;
		}

		v = ssa_emit(proc, ssa_make_instr_shuffle_vector(proc, v, indices, index_count));
		return v;
	}

	gb_printf_err("Not Identical %s != %s\n", type_to_string(src_type), type_to_string(t));
	gb_printf_err("Not Identical %s != %s\n", type_to_string(src), type_to_string(dst));


	GB_PANIC("Invalid type conversion: `%s` to `%s`", type_to_string(src_type), type_to_string(t));

	return NULL;
}


ssaValue *ssa_emit_transmute(ssaProcedure *proc, ssaValue *value, Type *t) {
	Type *src_type = ssa_type(value);
	if (are_types_identical(t, src_type)) {
		return value;
	}

	Type *src = get_base_type(src_type);
	Type *dst = get_base_type(t);
	if (are_types_identical(t, src_type))
		return value;

	i64 sz = type_size_of(proc->module->sizes, proc->module->allocator, src);
	i64 dz = type_size_of(proc->module->sizes, proc->module->allocator, dst);

	if (sz == dz) {
		return ssa_emit(proc, ssa_make_instr_conv(proc, ssaConv_bitcast, value, src, dst));
	}


	GB_PANIC("Invalid transmute conversion: `%s` to `%s`", type_to_string(src_type), type_to_string(t));

	return NULL;
}





ssaValue *ssa_build_single_expr(ssaProcedure *proc, AstNode *expr, TypeAndValue *tv) {
	switch (expr->kind) {
	case_ast_node(bl, BasicLit, expr);
		GB_PANIC("Non-constant basic literal");
	case_end;

	case_ast_node(i, Ident, expr);
		Entity *e = *map_get(&proc->module->info->uses, hash_pointer(expr));
		if (e->kind == Entity_Builtin) {
			GB_PANIC("TODO(bill): ssa_build_single_expr Entity_Builtin");
			return NULL;
		}

		auto *found = map_get(&proc->module->values, hash_pointer(e));
		if (found) {
			ssaValue *v = *found;
			if (v->kind == ssaValue_Proc)
				return v;
			return ssa_emit_load(proc, v);
		}
		return NULL;
	case_end;

	case_ast_node(pe, ParenExpr, expr);
		return ssa_build_single_expr(proc, unparen_expr(expr), tv);
	case_end;

	case_ast_node(de, DerefExpr, expr);
		return ssa_lvalue_load(proc, ssa_build_addr(proc, expr));
	case_end;

	case_ast_node(se, SelectorExpr, expr);
		return ssa_lvalue_load(proc, ssa_build_addr(proc, expr));
	case_end;

	case_ast_node(ue, UnaryExpr, expr);
		switch (ue->op.kind) {
		case Token_Pointer: {
			ssaValue *v = ssa_emit_zero_gep(proc, ssa_build_addr(proc, ue->expr).addr);
			ssa_set_type(v, type_of_expr(proc->module->info, expr));
			return v;
		}
		case Token_Add:
			return ssa_build_expr(proc, ue->expr);
		case Token_Sub: {
			// NOTE(bill): -`x` == 0 - `x`
			ssaValue *left = v_zero;
			ssaValue *right = ssa_build_expr(proc, ue->expr);
			return ssa_emit_arith(proc, ue->op, left, right, tv->type);
		} break;
		case Token_Not: // Boolean not
		case Token_Xor: { // Bitwise not
			// NOTE(bill): "not" `x` == `x` "xor" `-1`
			ExactValue neg_one = make_exact_value_integer(-1);
			ssaValue *left = ssa_build_expr(proc, ue->expr);
			ssaValue *right = ssa_make_value_constant(proc->module->allocator, tv->type, neg_one);
			return ssa_emit_arith(proc, ue->op, left, right, tv->type);
		} break;
		}
	case_end;

	case_ast_node(be, BinaryExpr, expr);
		switch (be->op.kind) {
		case Token_Add:
		case Token_Sub:
		case Token_Mul:
		case Token_Quo:
		case Token_Mod:
		case Token_And:
		case Token_Or:
		case Token_Xor:
		case Token_AndNot:
		case Token_Shl:
		case Token_Shr:
			return ssa_emit_arith(proc, be->op,
			                      ssa_build_expr(proc, be->left),
			                      ssa_build_expr(proc, be->right),
			                      tv->type);


		case Token_CmpEq:
		case Token_NotEq:
		case Token_Lt:
		case Token_LtEq:
		case Token_Gt:
		case Token_GtEq: {
			ssaValue *left  = ssa_build_expr(proc, be->left);
			ssaValue *right = ssa_build_expr(proc, be->right);
			ssaValue *cmp = ssa_emit_comp(proc, be->op, left, right);
			return ssa_emit_conv(proc, cmp, default_type(tv->type));
		} break;

		case Token_as:
			return ssa_emit_conv(proc, ssa_build_expr(proc, be->left), tv->type);

		case Token_transmute:
			return ssa_emit_transmute(proc, ssa_build_expr(proc, be->left), tv->type);

		default:
			GB_PANIC("Invalid binary expression");
			break;
		}
	case_end;

	case_ast_node(pl, ProcLit, expr);
		if (proc->children == NULL) {
			gb_array_init(proc->children, gb_heap_allocator());
		}
		// NOTE(bill): Generate a new name
		// parent$count
		isize name_len = proc->name.len + 1 + 8 + 1;
		u8 *name_text = gb_alloc_array(proc->module->allocator, u8, name_len);
		name_len = gb_snprintf(cast(char *)name_text, name_len, "%.*s$%d", LIT(proc->name), cast(i32)gb_array_count(proc->children));
		String name = make_string(name_text, name_len-1);

		Type *type = type_of_expr(proc->module->info, expr);
		ssaValue *value = ssa_make_value_procedure(proc->module->allocator,
		                                           proc->module, type, pl->type, pl->body, name);

		value->Proc.tags = pl->tags;

		gb_array_append(proc->children, &value->Proc);
		ssa_build_proc(value, proc);

		return value;
	case_end;


	case_ast_node(cl, CompoundLit, expr);
		Type *type = type_of_expr(proc->module->info, expr);
		Type *base_type = get_base_type(type);
		ssaValue *v = ssa_add_local_generated(proc, type);

		Type *et = NULL;
		switch (base_type->kind) {
		case Type_Vector: et = base_type->Vector.elem; break;
		case Type_Array:  et = base_type->Array.elem;  break;
		case Type_Slice:  et = base_type->Slice.elem;  break;
		}

		switch (base_type->kind) {
		default: GB_PANIC("Unknown CompoundLit type: %s", type_to_string(type)); break;

		case Type_Vector: {
			isize index = 0;
			ssaValue *result = ssa_emit_load(proc, v);
			for (AstNode *elem = cl->elem_list;
				elem != NULL;
				elem = elem->next, index++) {
				ssaValue *field_elem = ssa_build_expr(proc, elem);
				Type *t = ssa_type(field_elem);
				GB_ASSERT(t->kind != Type_Tuple);
				ssaValue *ev = ssa_emit_conv(proc, field_elem, et);
				ssaValue *i = ssa_make_value_constant(proc->module->allocator, t_int, make_exact_value_integer(index));
				result = ssa_emit(proc, ssa_make_instr_insert_element(proc, result, ev, i));
			}
			if (index == 1 && base_type->Vector.count > 1) {
				isize index_count = base_type->Vector.count;
				i32 *indices = gb_alloc_array(proc->module->allocator, i32, index_count);
				for (isize i = 0; i < index_count; i++) {
					indices[i] = 0;
				}
				ssaValue *sv = ssa_emit(proc, ssa_make_instr_shuffle_vector(proc, result, indices, index_count));
				ssa_emit_store(proc, v, sv);
				return ssa_emit_load(proc, v);
			}

			return result;
		} break;

		case Type_Struct: {
			auto *st = &base_type->Struct;
			if (cl->elem_list != NULL) {
				isize index = 0;
				AstNode *elem = cl->elem_list;
				for (;
				     elem != NULL;
				     elem = elem->next, index++) {
					isize field_index = index;
					ssaValue *field_expr = NULL;
					Entity *field = NULL;

					if (elem->kind == AstNode_FieldValue) {
						ast_node(kv, FieldValue, elem);
						Selection sel = lookup_field(base_type, kv->field->Ident.token.string);
						field_index = sel.index[0];
						field_expr = ssa_build_expr(proc, kv->value);
					} else {
						field_expr = ssa_build_expr(proc, elem);
					}

					GB_ASSERT(ssa_type(field_expr)->kind != Type_Tuple);

					field = st->fields[field_index];

					Type *ft = field->type;
					ssaValue *fv = ssa_emit_conv(proc, field_expr, ft);
					ssaValue *gep = ssa_emit_struct_gep(proc, v, field_index, ft);
					ssa_emit_store(proc, gep, fv);
				}
			}
		} break;
		case Type_Array: {
			isize index = 0;
			for (AstNode *elem = cl->elem_list;
				elem != NULL;
				elem = elem->next, index++) {
				ssaValue *field_expr = ssa_build_expr(proc, elem);
				Type *t = ssa_type(field_expr);
				GB_ASSERT(t->kind != Type_Tuple);
				ssaValue *ev = ssa_emit_conv(proc, field_expr, et);
				ssaValue *gep = ssa_emit_struct_gep(proc, v, index, et);
				ssa_emit_store(proc, gep, ev);
			}
		} break;
		case Type_Slice: {
			i64 count = cl->elem_count;
			ssaValue *array = ssa_add_local_generated(proc, make_type_array(proc->module->allocator, et, count));
			isize index = 0;
			for (AstNode *elem = cl->elem_list;
				elem != NULL;
				elem = elem->next, index++) {
				ssaValue *field_expr = ssa_build_expr(proc, elem);
				Type *t = ssa_type(field_expr);
				GB_ASSERT(t->kind != Type_Tuple);
				ssaValue *ev = ssa_emit_conv(proc, field_expr, et);
				ssaValue *gep = ssa_emit_struct_gep(proc, array, index, et);
				ssa_emit_store(proc, gep, ev);
			}

			ssaValue *elem = ssa_emit_struct_gep(proc, array, v_zero32,
			                                     make_type_pointer(proc->module->allocator, et));
			ssaValue *len = ssa_array_len(proc, array);
			ssaValue *gep = NULL;
			gep = ssa_emit_struct_gep(proc, v, v_zero32, ssa_type(elem));
			ssa_emit_store(proc, gep, elem);
			gep = ssa_emit_struct_gep(proc, v, v_one32, t_int);
			ssa_emit_store(proc, gep, len);
			gep = ssa_emit_struct_gep(proc, v, v_two32, t_int);
			ssa_emit_store(proc, gep, len);
		} break;
		}

		return ssa_emit_load(proc, v);
	case_end;

	case_ast_node(ce, CallExpr, expr);
		AstNode *p = unparen_expr(ce->proc);
		if (p->kind == AstNode_Ident) {
			Entity **found = map_get(&proc->module->info->uses, hash_pointer(p));
			if (found && (*found)->kind == Entity_Builtin) {
				Entity *e = *found;
				switch (e->Builtin.id) {
				case BuiltinProc_len: {
					// len :: proc(Type) -> int
					// NOTE(bill): len of an array is a constant expression
					ssaValue *v = ssa_build_addr(proc, ce->arg_list).addr;
					Type *t = get_base_type(ssa_type(v));
					if (t == t_string)
						return ssa_string_len(proc, v);
					else if (t->kind == Type_Slice)
						return ssa_slice_len(proc, v);
				} break;
				case BuiltinProc_cap: {
					// cap :: proc(Type) -> int
					// NOTE(bill): cap of an array is a constant expression
					ssaValue *v = ssa_build_addr(proc, ce->arg_list).addr;
					Type *t = get_base_type(ssa_type(v));
					return ssa_slice_cap(proc, v);
				} break;
				case BuiltinProc_copy: {
					// copy :: proc(dst, src: []Type) -> int
					AstNode *dst_node = ce->arg_list;
					AstNode *src_node = ce->arg_list->next;
					ssaValue *dst_slice = ssa_build_expr(proc, dst_node);
					ssaValue *src_slice = ssa_build_expr(proc, src_node);
					Type *slice_type = get_base_type(ssa_type(dst_slice));
					GB_ASSERT(slice_type->kind == Type_Slice);
					Type *elem_type = slice_type->Slice.elem;
					i64 size_of_elem = type_size_of(proc->module->sizes, proc->module->allocator, elem_type);

					ssaValue *d = ssa_add_local_generated(proc, slice_type);
					ssaValue *s = ssa_add_local_generated(proc, slice_type);
					ssa_emit_store(proc, d, dst_slice);
					ssa_emit_store(proc, s, src_slice);

					ssaValue *dst = ssa_emit_conv(proc, ssa_slice_elem(proc, d), t_rawptr);
					ssaValue *src = ssa_emit_conv(proc, ssa_slice_elem(proc, s), t_rawptr);

					ssaValue *len_dst = ssa_slice_len(proc, d);
					ssaValue *len_src = ssa_slice_len(proc, s);

					Token lt = {Token_Lt};
					ssaValue *cond = ssa_emit_comp(proc, lt, len_dst, len_src);
					ssaValue *len = ssa_emit_select(proc, cond, len_dst, len_src);
					Token mul = {Token_Mul};
					ssaValue *elem_size = ssa_make_value_constant(proc->module->allocator, t_int,
					                                              make_exact_value_integer(size_of_elem));
					ssaValue *byte_count = ssa_emit_arith(proc, mul, len, elem_size, t_int);


					i32 align = cast(i32)type_align_of(proc->module->sizes, proc->module->allocator, elem_type);
					b32 is_volatile = false;

					ssa_emit(proc, ssa_make_instr_copy_memory(proc, dst, src, byte_count, align, is_volatile));
					return len;
				} break;
				case BuiltinProc_append: {
					// append :: proc(s: ^[]Type, item: Type) -> bool
					AstNode *sptr_node = ce->arg_list;
					AstNode *item_node = ce->arg_list->next;
					ssaValue *slice = ssa_build_addr(proc, sptr_node).addr;

					ssaValue *elem = ssa_slice_elem(proc, slice);
					ssaValue *len = ssa_slice_len(proc, slice);
					ssaValue *cap = ssa_slice_cap(proc, slice);

					Type *elem_type = type_deref(ssa_type(elem));

					ssaValue *item_value = ssa_build_expr(proc, item_node);
					item_value = ssa_emit_conv(proc, item_value, elem_type);

					ssaValue *item = ssa_add_local_generated(proc, elem_type);
					ssa_emit_store(proc, item, item_value);


					// NOTE(bill): Check if can append is possible
					Token lt = {Token_Lt};
					ssaValue *cond = ssa_emit_comp(proc, lt, len, cap);
					ssaBlock *able = ssa_add_block(proc, NULL, make_string("builtin.append.able"));
					ssaBlock *done = ssa__make_block(proc, NULL, make_string("builtin.append.done"));

					ssa_emit_if(proc, cond, able, done);
					proc->curr_block = able;

					// Add new slice item
					ssaValue *offset = ssa_emit_ptr_offset(proc, elem, len);
					i64 item_size = type_size_of(proc->module->sizes, proc->module->allocator, elem_type);
					ssaValue *byte_count = ssa_make_value_constant(proc->module->allocator, t_int,
					                                               make_exact_value_integer(item_size));
					offset = ssa_emit_conv(proc, offset, t_rawptr);
					item = ssa_emit_ptr_offset(proc, item, v_zero);
					ssa_set_type(item, make_type_pointer(proc->module->allocator, ssa_type(item)));
					item = ssa_emit_conv(proc, item, t_rawptr);
					ssa_emit(proc, ssa_make_instr_copy_memory(proc, offset, item, byte_count, 1, false));

					// Increment slice length
					Token add = {Token_Add};
					ssaValue *new_len = ssa_emit_arith(proc, add, len, v_one, t_int);
					ssaValue *gep = ssa_emit_struct_gep(proc, slice, v_one32, t_int);
					ssa_emit_store(proc, gep, new_len);

					ssa_emit_jump(proc, done);
					gb_array_append(proc->blocks, done);
					proc->curr_block = done;

					return ssa_emit_conv(proc, cond, t_bool);
				} break;

				case BuiltinProc_swizzle: {
					ssaValue *vector = ssa_build_expr(proc, ce->arg_list);
					isize index_count = ce->arg_list_count-1;
					if (index_count == 0) {
						return vector;
					}

					i32 *indices = gb_alloc_array(proc->module->allocator, i32, index_count);
					isize index = 0;
					for (AstNode *arg = ce->arg_list->next; arg != NULL; arg = arg->next) {
						TypeAndValue *tv = type_and_value_of_expression(proc->module->info, arg);
						GB_ASSERT(is_type_integer(tv->type));
						GB_ASSERT(tv->value.kind == ExactValue_Integer);
						indices[index++] = cast(i32)tv->value.value_integer;
					}

					return ssa_emit(proc, ssa_make_instr_shuffle_vector(proc, vector, indices, index_count));

				} break;

				case BuiltinProc_ptr_offset: {
					ssaValue *ptr = ssa_build_expr(proc, ce->arg_list);
					ssaValue *offset = ssa_build_expr(proc, ce->arg_list->next);
					return ssa_emit_ptr_offset(proc, ptr, offset);
				} break;

				case BuiltinProc_ptr_sub: {
					ssaValue *ptr_a = ssa_build_expr(proc, ce->arg_list);
					ssaValue *ptr_b = ssa_build_expr(proc, ce->arg_list->next);
					Type *ptr_type = get_base_type(ssa_type(ptr_a));
					GB_ASSERT(ptr_type->kind == Type_Pointer);
					isize elem_size = type_size_of(proc->module->sizes, proc->module->allocator, ptr_type->Pointer.elem);
					Token sub = {Token_Sub};
					ssaValue *v = ssa_emit_arith(proc, sub, ptr_a, ptr_b, t_int);
					if (elem_size > 1) {
						Token quo = {Token_Quo};
						ssaValue *ez = ssa_make_value_constant(proc->module->allocator, t_int,
						                                       make_exact_value_integer(elem_size));
						v = ssa_emit_arith(proc, quo, v, ez, t_int);
					}

					return v;
				} break;

				case BuiltinProc_slice_ptr: {
					ssaValue *ptr = ssa_build_expr(proc, ce->arg_list);
					ssaValue *len = ssa_build_expr(proc, ce->arg_list->next);
					ssaValue *cap = len;

					len = ssa_emit_conv(proc, len, t_int);

					if (ce->arg_list->next->next != NULL) {
						cap = ssa_build_expr(proc, ce->arg_list->next->next);
						cap = ssa_emit_conv(proc, cap, t_int);
					}


					Type *slice_type = make_type_slice(proc->module->allocator, type_deref(ssa_type(ptr)));
					ssaValue *slice = ssa_add_local_generated(proc, slice_type);
					ssa_emit_store(proc, ssa_emit_struct_gep(proc, slice, v_zero32, ssa_type(ptr)), ptr);
					ssa_emit_store(proc, ssa_emit_struct_gep(proc, slice, v_one32,  t_int),         len);
					ssa_emit_store(proc, ssa_emit_struct_gep(proc, slice, v_two32,  t_int),         cap);
					return ssa_emit_load(proc, slice);
				} break;
				}
			}
		}


		// NOTE(bill): Regular call
		ssaValue *value = ssa_build_expr(proc, ce->proc);
		Type *proc_type_ = get_base_type(ssa_type(value));
		GB_ASSERT(proc_type_->kind == Type_Proc);
		auto *type = &proc_type_->Proc;

		isize arg_index = 0;
		isize arg_count = type->param_count;
		ssaValue **args = gb_alloc_array(proc->module->allocator, ssaValue *, arg_count);

		for (AstNode *arg = ce->arg_list; arg != NULL; arg = arg->next) {
			ssaValue *a = ssa_build_expr(proc, arg);
			Type *at = ssa_type(a);
			if (at->kind == Type_Tuple) {
				for (isize i = 0; i < at->Tuple.variable_count; i++) {
					Entity *e = at->Tuple.variables[i];
					ssaValue *v = ssa_emit_struct_ev(proc, a, i, e->type);
					args[arg_index++] = v;
				}
			} else {
				args[arg_index++] = a;
			}
		}

		auto *pt = &proc_type_->Proc.params->Tuple;
		for (isize i = 0; i < arg_count; i++) {
			args[i] = ssa_emit_conv(proc, args[i], pt->variables[i]->type);
		}

		ssaValue *call = ssa_make_instr_call(proc, value, args, arg_count, type->results);
		return ssa_emit(proc, call);
	case_end;

	case_ast_node(se, SliceExpr, expr);
		return ssa_emit_load(proc, ssa_build_addr(proc, expr).addr);
	case_end;

	case_ast_node(ie, IndexExpr, expr);
		return ssa_emit_load(proc, ssa_build_addr(proc, expr).addr);
	case_end;
	}

	GB_PANIC("Unexpected expression: %.*s", LIT(ast_node_strings[expr->kind]));
	return NULL;
}


ssaValue *ssa_build_expr(ssaProcedure *proc, AstNode *expr) {
	expr = unparen_expr(expr);

	TypeAndValue *tv = map_get(&proc->module->info->types, hash_pointer(expr));
	GB_ASSERT_NOT_NULL(tv);

	if (tv->value.kind != ExactValue_Invalid) {
		if (tv->value.kind == ExactValue_String) {
			// TODO(bill): Optimize by not allocating everytime
			ssaValue *array = ssa_add_global_string_array(proc, tv->value);
			ssaValue *elem = ssa_array_elem(proc, array);
			return ssa_emit_load(proc, ssa_emit_string(proc, elem, ssa_array_len(proc, array)));
		}

		return ssa_make_value_constant(proc->module->allocator, tv->type, tv->value);
	}

	ssaValue *value = NULL;
	if (tv->mode == Addressing_Variable) {
		ssaAddr addr = ssa_build_addr(proc, expr);
		value = ssa_lvalue_load(proc, addr);
	} else {
		value = ssa_build_single_expr(proc, expr, tv);
	}

	return value;
}

ssaValue *ssa_emit_deep_field_gep(ssaProcedure *proc, Type *type, ssaValue *e, Selection sel) {
	GB_ASSERT(gb_array_count(sel.index) > 0);

	gb_for_array(i, sel.index) {
		isize index = sel.index[i];
		if (is_type_pointer(type)) {
			type = type_deref(type);
			e = ssa_emit_load(proc, e);
			e = ssa_emit_ptr_offset(proc, e, v_zero);
			ssa_set_type(e, type);
		}
		type = get_base_type(type);


		if (type->kind == Type_Union) {
			ssaValue *v = ssa_emit_ptr_offset(proc, e, v_zero);
			ssa_set_type(v, make_type_pointer(proc->module->allocator, type));
			type = type->Union.fields[index]->type;
			e = ssa_emit_conv(proc, v, make_type_pointer(proc->module->allocator, type));
			e = ssa_emit_ptr_offset(proc, e, v_zero);
			ssa_set_type(e, type);
		} else {
			type = type->Union.fields[index]->type;
			e = ssa_emit_struct_gep(proc, e, index, type);
		}
	}

	return e;
}


ssaAddr ssa_build_addr(ssaProcedure *proc, AstNode *expr) {
	switch (expr->kind) {
	case_ast_node(i, Ident, expr);
		if (ssa_is_blank_ident(expr)) {
			ssaAddr val = {};
			return val;
		}

		Entity *e = entity_of_ident(proc->module->info, expr);
		ssaValue *v = NULL;
		ssaValue **found = map_get(&proc->module->values, hash_pointer(e));
		if (found) {
			v = *found;
		} else {
			GB_PANIC("Unknown value: %s, entity: %p\n", expr_to_string(expr), e);
		}
		return ssa_make_addr(v, expr);
	case_end;

	case_ast_node(pe, ParenExpr, expr);
		return ssa_build_addr(proc, unparen_expr(expr));
	case_end;

	case_ast_node(se, SelectorExpr, expr);
		Type *type = get_base_type(type_of_expr(proc->module->info, se->expr));

		Selection sel = lookup_field(type, unparen_expr(se->selector)->Ident.token.string);
		GB_ASSERT(sel.entity != NULL);

		ssaValue *e = ssa_build_addr(proc, se->expr).addr;
		e = ssa_emit_deep_field_gep(proc, type, e, sel);
		return ssa_make_addr(e, expr);
	case_end;

	case_ast_node(ue, UnaryExpr, expr);
		switch (ue->op.kind) {
		case Token_Pointer: {
			ssaAddr lval = ssa_build_addr(proc, ue->expr);
			// ssaValue *v = ssa_emit_zero_gep(proc, lval.addr);
			// Type *t = ssa_type(lval.addr);
			// ssa_set_type(lval.addr, make_type_pointer(proc->module->allocator, t));
			// return ssa_make_addr(v, expr);
			return lval;
		}
		default:
			GB_PANIC("Invalid unary expression for ssa_build_addr");
		}
	case_end;

	case_ast_node(be, BinaryExpr, expr);
		switch (be->op.kind) {
		case Token_as: {
			// HACK(bill): Do have to make new variable to do this?
			// NOTE(bill): Needed for dereference of pointer conversion
			Type *type = type_of_expr(proc->module->info, expr);
			ssaValue *v = ssa_add_local_generated(proc, type);
			ssa_emit_store(proc, v, ssa_emit_conv(proc, ssa_build_expr(proc, be->left), type));
			return ssa_make_addr(v, expr);
		}
		case Token_transmute: {
			// HACK(bill): Do have to make new variable to do this?
			// NOTE(bill): Needed for dereference of pointer conversion
			Type *type = type_of_expr(proc->module->info, expr);
			ssaValue *v = ssa_add_local_generated(proc, type);
			ssa_emit_store(proc, v, ssa_emit_transmute(proc, ssa_build_expr(proc, be->left), type));
			return ssa_make_addr(v, expr);
		}
		default:
			GB_PANIC("Invalid binary expression for ssa_build_addr: %.*s\n", LIT(be->op.string));
			break;
		}
	case_end;

	case_ast_node(ie, IndexExpr, expr);
		ssaValue *v = NULL;
		Type *t = get_base_type(type_of_expr(proc->module->info, ie->expr));
		ssaValue *elem = NULL;
		switch (t->kind) {
		case Type_Vector: {
			// HACK(bill): Fix how lvalues for vectors work
			ssaValue *vector = ssa_build_addr(proc, ie->expr).addr;
			ssaValue *index = ssa_emit_conv(proc, ssa_build_expr(proc, ie->index), t_int);
			return ssa_make_addr_vector(vector, index, expr);
		} break;


		case Type_Array: {
			ssaValue *array = ssa_build_addr(proc, ie->expr).addr;
			elem = ssa_array_elem(proc, array);
		} break;
		case Type_Slice: {
			ssaValue *slice = ssa_build_addr(proc, ie->expr).addr;
			elem = ssa_slice_elem(proc, slice);
		} break;
		case Type_Basic: { // Basic_string
			TypeAndValue *tv = map_get(&proc->module->info->types, hash_pointer(ie->expr));
			if (tv->mode == Addressing_Constant) {
				ssaValue *array = ssa_add_global_string_array(proc, tv->value);
				elem = ssa_array_elem(proc, array);
			} else {
				elem = ssa_string_elem(proc, ssa_build_addr(proc, ie->expr).addr);
			}
		} break;
		case Type_Pointer: {
			ssaValue *array = ssa_emit_load(proc, ssa_build_expr(proc, ie->expr));
			elem = ssa_array_elem(proc, array);
		} break;
		}

		ssaValue *index = ssa_emit_conv(proc, ssa_build_expr(proc, ie->index), t_int);
		v = ssa_emit_ptr_offset(proc, elem, index);

		Type *lval_type = type_deref(ssa_type(v));
		// gb_printf("%s\n", type_to_string(lval_type));
		ssa_set_type(v, lval_type);
		return ssa_make_addr(v, expr);
	case_end;

	case_ast_node(se, SliceExpr, expr);
		ssaValue *low  = NULL;
		ssaValue *high = NULL;
		ssaValue *max  = NULL;

		if (se->low  != NULL)    low  = ssa_build_expr(proc, se->low);
		if (se->high != NULL)    high = ssa_build_expr(proc, se->high);
		if (se->triple_indexed)  max  = ssa_build_expr(proc, se->max);
		Type *type = type_of_expr(proc->module->info, expr);

		switch (type->kind) {
		case Type_Slice:
		case Type_Array: {
			ssaValue *base = ssa_build_addr(proc, se->expr).addr;
			return ssa_make_addr(ssa_emit_slice(proc, type, base, low, high, max), expr);
		} break;
		case Type_Basic: {
			// NOTE(bill): max is not needed
			ssaValue *base = ssa_build_addr(proc, se->expr).addr;
			return ssa_make_addr(ssa_emit_substring(proc, base, low, high), expr);
		} break;
		}

		GB_PANIC("Unknown slicable type");
	case_end;

	case_ast_node(de, DerefExpr, expr);
		ssaValue *e = ssa_build_expr(proc, de->expr);
		ssaValue *gep = ssa_emit_zero_gep(proc, e);
		// HACK(bill): need to deref here as stack variables are of type pointer
		// and addresses are already pointers
		// TODO(bill): Completely redo the type system for SSA
		Type *t = type_deref(ssa_type(e));
		gep->Instr.GetElementPtr.result_type  = t;
		gep->Instr.GetElementPtr.elem_type = t;
		return ssa_make_addr(gep, expr);
	case_end;
	}

	TokenPos token_pos = ast_node_token(expr).pos;
	GB_PANIC("Unexpected address expression\n"
	         "\tAstNode: %.*s @ "
	         "%.*s(%td:%td)\n",
	         LIT(ast_node_strings[expr->kind]),
	         LIT(token_pos.file), token_pos.line, token_pos.column);


	return ssa_make_addr(NULL, NULL);
}

void ssa_build_assign_op(ssaProcedure *proc, ssaAddr lhs, ssaValue *value, Token op) {
	ssaValue *old_value = ssa_lvalue_load(proc, lhs);
	ssaValue *change = ssa_emit_conv(proc, value, ssa_type(old_value));
	ssaValue *new_value = ssa_emit_arith(proc, op, old_value, change, ssa_type(old_value));
	ssa_lvalue_store(proc, lhs, new_value);
}

void ssa_build_cond(ssaProcedure *proc, AstNode *cond, ssaBlock *true_block, ssaBlock *false_block) {
	switch (cond->kind) {
	case_ast_node(pe, ParenExpr, cond);
		ssa_build_cond(proc, pe->expr, true_block, false_block);
		return;
	case_end;

	case_ast_node(ue, UnaryExpr, cond);
		if (ue->op.kind == Token_Not) {
			ssa_build_cond(proc, ue->expr, false_block, true_block);
			return;
		}
	case_end;

	case_ast_node(be, BinaryExpr, cond);
		if (be->op.kind == Token_CmpAnd) {
			ssaBlock *block = ssa_add_block(proc, NULL, make_string("cmp-and"));
			ssa_build_cond(proc, be->left, block, false_block);
			proc->curr_block = block;
			ssa_build_cond(proc, be->right, true_block, false_block);
			return;
		} else if (be->op.kind == Token_CmpOr) {
			ssaBlock *block = ssa_add_block(proc, NULL, make_string("cmp-or"));
			ssa_build_cond(proc, be->left, true_block, block);
			proc->curr_block = block;
			ssa_build_cond(proc, be->right, true_block, false_block);
			return;
		}
	case_end;
	}

	ssaValue *expr = ssa_build_expr(proc, cond);
	ssa_emit_if(proc, expr, true_block, false_block);
}



void ssa_build_stmt_list(ssaProcedure *proc, AstNode *list) {
	for (AstNode *stmt = list ; stmt != NULL; stmt = stmt->next)
		ssa_build_stmt(proc, stmt);
}

void ssa_build_stmt(ssaProcedure *proc, AstNode *node) {
	switch (node->kind) {
	case_ast_node(bs, EmptyStmt, node);
	case_end;

	case_ast_node(vd, VarDecl, node);
		if (vd->kind == Declaration_Mutable) {
			if (vd->name_count == vd->value_count) { // 1:1 assigment
				gbArray(ssaAddr)  lvals;
				gbArray(ssaValue *) inits;
				gb_array_init_reserve(lvals, gb_heap_allocator(), vd->name_count);
				gb_array_init_reserve(inits, gb_heap_allocator(), vd->name_count);
				defer (gb_array_free(lvals));
				defer (gb_array_free(inits));

				for (AstNode *name = vd->name_list; name != NULL; name = name->next) {
					ssaAddr lval = ssa_make_addr(NULL, NULL);
					if (!ssa_is_blank_ident(name)) {
						ssa_add_local_for_identifier(proc, name);
						lval = ssa_build_addr(proc, name);
						GB_ASSERT(lval.addr != NULL);
					}

					gb_array_append(lvals, lval);
				}

				for (AstNode *value = vd->value_list; value != NULL; value = value->next) {
					ssaValue *init = ssa_build_expr(proc, value);
					gb_array_append(inits, init);
				}


				gb_for_array(i, inits) {
					ssaValue *v = ssa_emit_conv(proc, inits[i], ssa_type(lvals[i]));
					ssa_lvalue_store(proc, lvals[i], v);
				}

			} else if (vd->value_count == 0) { // declared and zero-initialized
				for (AstNode *name = vd->name_list; name != NULL; name = name->next) {
					if (!ssa_is_blank_ident(name)) {
						ssa_add_local_for_identifier(proc, name);
					}
				}
			} else { // Tuple(s)
				gbArray(ssaAddr)  lvals;
				gbArray(ssaValue *) inits;
				gb_array_init_reserve(lvals, gb_heap_allocator(), vd->name_count);
				gb_array_init_reserve(inits, gb_heap_allocator(), vd->name_count);
				defer (gb_array_free(lvals));
				defer (gb_array_free(inits));

				for (AstNode *name = vd->name_list; name != NULL; name = name->next) {
					ssaAddr lval = ssa_make_addr(NULL, NULL);
					if (!ssa_is_blank_ident(name)) {
						ssa_add_local_for_identifier(proc, name);
						lval = ssa_build_addr(proc, name);
					}

					gb_array_append(lvals, lval);
				}

				for (AstNode *value = vd->value_list; value != NULL; value = value->next) {
					ssaValue *init = ssa_build_expr(proc, value);
					Type *t = ssa_type(init);
					if (t->kind == Type_Tuple) {
						for (isize i = 0; i < t->Tuple.variable_count; i++) {
							Entity *e = t->Tuple.variables[i];
							ssaValue *v = ssa_emit_struct_ev(proc, init, i, e->type);
							gb_array_append(inits, v);
						}
					} else {
						gb_array_append(inits, init);
					}
				}


				gb_for_array(i, inits) {
					ssaValue *v = ssa_emit_conv(proc, inits[i], ssa_type(lvals[i]));
					ssa_lvalue_store(proc, lvals[i], v);
				}
			}
		}
	case_end;

	case_ast_node(pd, ProcDecl, node);
		if (proc->children == NULL) {
			gb_array_init(proc->children, gb_heap_allocator());
		}


		if (pd->body != NULL) {
			// NOTE(bill): Generate a new name
			// parent$name-guid
			String pd_name = pd->name->Ident.token.string;
			isize name_len = proc->name.len + 1 + pd_name.len + 1 + 10 + 1;
			u8 *name_text = gb_alloc_array(proc->module->allocator, u8, name_len);
			i32 guid = cast(i32)gb_array_count(proc->children);
			name_len = gb_snprintf(cast(char *)name_text, name_len, "%.*s$%.*s-%d", LIT(proc->name), LIT(pd_name), guid);
			String name = make_string(name_text, name_len-1);

			Entity **found = map_get(&proc->module->info->definitions, hash_pointer(pd->name));
			GB_ASSERT_MSG(found != NULL, "Unable to find: %.*s", LIT(pd->name->Ident.token.string));
			Entity *e = *found;
			ssaValue *value = ssa_make_value_procedure(proc->module->allocator,
			                                           proc->module, e->type, pd->type, pd->body, name);

			value->Proc.tags = pd->tags;

			ssa_module_add_value(proc->module, e, value);
			gb_array_append(proc->children, &value->Proc);
			ssa_build_proc(value, proc);
		} else {
			String name = pd->name->Ident.token.string;
			if (pd->foreign_name.len > 0) {
				name = pd->foreign_name;
			}

			Entity **found = map_get(&proc->module->info->definitions, hash_pointer(pd->name));
			GB_ASSERT(found != NULL);
			Entity *e = *found;
			ssaValue *value = ssa_make_value_procedure(proc->module->allocator,
			                                           proc->module, e->type, pd->type, pd->body, name);
			ssa_module_add_value(proc->module, e, value);
			gb_array_append(proc->children, &value->Proc);
			ssa_build_proc(value, proc);
		}
	case_end;

	case_ast_node(td, TypeDecl, node);

		// NOTE(bill): Generate a new name
		// parent_proc.name-guid
		String td_name = td->name->Ident.token.string;
		isize name_len = proc->name.len + 1 + td_name.len + 1 + 10 + 1;
		u8 *name_text = gb_alloc_array(proc->module->allocator, u8, name_len);
		i32 guid = cast(i32)gb_array_count(proc->module->nested_type_names);
		name_len = gb_snprintf(cast(char *)name_text, name_len, "%.*s.%.*s-%d", LIT(proc->name), LIT(td_name), guid);
		String name = make_string(name_text, name_len-1);

		Entity **found = map_get(&proc->module->info->definitions, hash_pointer(td->name));
		GB_ASSERT(found != NULL);
		Entity *e = *found;
		ssaValue *value = ssa_make_value_type_name(proc->module->allocator,
		                                           name, e->type);
		// HACK(bill): Override name of type so printer prints it correctly
		e->type->Named.name = name;
		ssa_module_add_value(proc->module, e, value);
		gb_array_append(proc->module->nested_type_names, value);
	case_end;

	case_ast_node(ids, IncDecStmt, node);
		Token op = ids->op;
		if (op.kind == Token_Increment) {
			op.kind = Token_Add;
		} else if (op.kind == Token_Decrement) {
			op.kind = Token_Sub;
		}
		ssaAddr lval = ssa_build_addr(proc, ids->expr);
		ssaValue *one = ssa_emit_conv(proc, v_one, ssa_type(lval));
		ssa_build_assign_op(proc, lval, one, op);

	case_end;

	case_ast_node(as, AssignStmt, node);
		switch (as->op.kind) {
		case Token_Eq: {
			gbArray(ssaAddr) lvals;
			gb_array_init(lvals, gb_heap_allocator());
			defer (gb_array_free(lvals));

			for (AstNode *lhs = as->lhs_list;
			     lhs != NULL;
			     lhs = lhs->next) {
				ssaAddr lval = {};
				if (!ssa_is_blank_ident(lhs)) {
					lval = ssa_build_addr(proc, lhs);
				}
				gb_array_append(lvals, lval);
			}

			if (as->lhs_count == as->rhs_count) {
				if (as->lhs_count == 1) {
					AstNode *rhs = as->rhs_list;
					ssaValue *init = ssa_build_expr(proc, rhs);
					ssa_lvalue_store(proc, lvals[0], init);
				} else {
					gbArray(ssaValue *) inits;
					gb_array_init_reserve(inits, gb_heap_allocator(), gb_array_count(lvals));
					defer (gb_array_free(inits));

					for (AstNode *rhs = as->rhs_list; rhs != NULL; rhs = rhs->next) {
						ssaValue *init = ssa_build_expr(proc, rhs);
						gb_array_append(inits, init);
					}

					gb_for_array(i, inits) {
						ssa_lvalue_store(proc, lvals[i], inits[i]);
					}
				}
			} else {
				gbArray(ssaValue *) inits;
				gb_array_init_reserve(inits, gb_heap_allocator(), gb_array_count(lvals));
				defer (gb_array_free(inits));

				for (AstNode *rhs = as->rhs_list; rhs != NULL; rhs = rhs->next) {
					ssaValue *init = ssa_build_expr(proc, rhs);
					Type *t = ssa_type(init);
					// TODO(bill): refactor for code reuse as this is repeated a bit
					if (t->kind == Type_Tuple) {
						for (isize i = 0; i < t->Tuple.variable_count; i++) {
							Entity *e = t->Tuple.variables[i];
							ssaValue *v = ssa_emit_struct_ev(proc, init, i, e->type);
							gb_array_append(inits, v);
						}
					} else {
						gb_array_append(inits, init);
					}
				}

				gb_for_array(i, inits) {
					ssa_lvalue_store(proc, lvals[i], inits[i]);
				}
			}

		} break;

		default: {
			// NOTE(bill): Only 1 += 1 is allowed, no tuples
			// +=, -=, etc
			Token op = as->op;
			i32 kind = op.kind;
			kind += Token_Add - Token_AddEq; // Convert += to +
			op.kind = cast(TokenKind)kind;
			ssaAddr lhs = ssa_build_addr(proc, as->lhs_list);
			ssaValue *value = ssa_build_expr(proc, as->rhs_list);
			ssa_build_assign_op(proc, lhs, value, op);
		} break;
		}
	case_end;

	case_ast_node(es, ExprStmt, node);
		// NOTE(bill): No need to use return value
		ssa_build_expr(proc, es->expr);
	case_end;

	case_ast_node(bs, BlockStmt, node);
		proc->scope_index++;
		ssa_build_stmt_list(proc, bs->list);
		ssa_emit_defer_stmts(proc, ssaDefer_Default, NULL);
		proc->scope_index--;
	case_end;

	case_ast_node(ds, DeferStmt, node);
		isize scope_index = proc->scope_index;
		if (ds->stmt->kind == AstNode_BlockStmt)
			scope_index--;
		ssaDefer d = {ds->stmt, scope_index, proc->curr_block};
		gb_array_append(proc->defer_stmts, d);
	case_end;

	case_ast_node(rs, ReturnStmt, node);
		ssaValue *v = NULL;
		auto *return_type_tuple  = &proc->type->Proc.results->Tuple;
		isize return_count = proc->type->Proc.result_count;
		if (rs->result_count == 1 && return_count > 1) {
			GB_PANIC("ReturnStmt tuple return statement");
		} else if (return_count == 1) {
			Entity *e = return_type_tuple->variables[0];
			v = ssa_build_expr(proc, rs->result_list);
			ssa_set_type(v, e->type);
		} else if (return_count == 0) {
			// No return values
		} else {
			// 1:1 multiple return values
			Type *ret_type = proc->type->Proc.results;
			v = ssa_add_local_generated(proc, ret_type);
			isize i = 0;
			AstNode *r = rs->result_list;
			for (;
			     i < return_count && r != NULL;
			     i++, r = r->next) {
				Entity *e = return_type_tuple->variables[i];
				ssaValue *res = ssa_build_expr(proc, r);
				ssa_set_type(res, e->type);
				ssaValue *field = ssa_emit_struct_gep(proc, v, i, e->type);
				ssa_emit_store(proc, field, res);
			}
			v = ssa_emit_load(proc, v);
		}
		ssa_emit_ret(proc, v);

	case_end;

	case_ast_node(is, IfStmt, node);
		if (is->init != NULL) {
			ssaBlock *init = ssa_add_block(proc, node, make_string("if.init"));
			ssa_emit_jump(proc, init);
			proc->curr_block = init;
			ssa_build_stmt(proc, is->init);
		}
		ssaBlock *then = ssa_add_block(proc, node, make_string("if.then"));
		ssaBlock *done = ssa__make_block(proc, node, make_string("if.done")); // NOTE(bill): Append later
		ssaBlock *else_ = done;
		if (is->else_stmt != NULL) {
			else_ = ssa_add_block(proc, is->else_stmt, make_string("if.else"));
		}

		ssa_build_cond(proc, is->cond, then, else_);
		proc->curr_block = then;

		proc->scope_index++;
		ssa_build_stmt(proc, is->body);
		ssa_emit_defer_stmts(proc, ssaDefer_Default, NULL);
		proc->scope_index--;

		ssa_emit_jump(proc, done);

		if (is->else_stmt != NULL) {
			proc->curr_block = else_;

			proc->scope_index++;
			ssa_build_stmt(proc, is->else_stmt);
			ssa_emit_defer_stmts(proc, ssaDefer_Default, NULL);
			proc->scope_index--;


			ssa_emit_jump(proc, done);
		}
		gb_array_append(proc->blocks, done);
		proc->curr_block = done;
	case_end;

	case_ast_node(fs, ForStmt, node);
		if (fs->init != NULL) {
			ssaBlock *init = ssa_add_block(proc, node, make_string("for.init"));
			ssa_emit_jump(proc, init);
			proc->curr_block = init;
			ssa_build_stmt(proc, fs->init);
		}
		ssaBlock *body = ssa_add_block(proc, node, make_string("for.body"));
		ssaBlock *done = ssa__make_block(proc, node, make_string("for.done")); // NOTE(bill): Append later

		ssaBlock *loop = body;

		if (fs->cond != NULL) {
			loop = ssa_add_block(proc, node, make_string("for.loop"));
		}
		ssaBlock *cont = loop;
		if (fs->post != NULL) {
			cont = ssa_add_block(proc, node, make_string("for.post"));

		}
		ssa_emit_jump(proc, loop);
		proc->curr_block = loop;
		if (loop != body) {
			ssa_build_cond(proc, fs->cond, body, done);
			proc->curr_block = body;
		}

		ssa_push_target_list(proc, done, cont, NULL);

		proc->scope_index++;
		ssa_build_stmt(proc, fs->body);
		ssa_emit_defer_stmts(proc, ssaDefer_Default, NULL);
		proc->scope_index--;

		ssa_pop_target_list(proc);
		ssa_emit_jump(proc, cont);

		if (fs->post != NULL) {
			proc->curr_block = cont;
			ssa_build_stmt(proc, fs->post);
			ssa_emit_jump(proc, loop);
		}


		gb_array_append(proc->blocks, done);
		proc->curr_block = done;

	case_end;

	case_ast_node(bs, BranchStmt, node);
		ssaBlock *block = NULL;
		switch (bs->token.kind) {
		case Token_break: {
			for (ssaTargetList *t = proc->target_list; t != NULL && block == NULL; t = t->prev) {
				block = t->break_;
			}
		} break;
		case Token_continue: {
			for (ssaTargetList *t = proc->target_list; t != NULL && block == NULL; t = t->prev) {
				block = t->continue_;
			}
		} break;
		case Token_fallthrough: {
			for (ssaTargetList *t = proc->target_list; t != NULL && block == NULL; t = t->prev) {
				block = t->fallthrough_;
			}
		} break;
		}
		if (block != NULL && bs->token.kind != Token_fallthrough) {
			ssa_emit_defer_stmts(proc, ssaDefer_Branch, block);
		}
		ssa_emit_jump(proc, block);
		ssa_emit_unreachable(proc);
	case_end;

	}
}


void ssa_emit_startup_runtime(ssaProcedure *proc) {
	GB_ASSERT(proc->parent == NULL && are_strings_equal(proc->name, make_string("main")));

	ssa_emit(proc, ssa_alloc_instr(proc, ssaInstr_StartupRuntime));
}

void ssa_insert_code_before_proc(ssaProcedure* proc, ssaProcedure *parent) {
	if (parent == NULL) {
		if (are_strings_equal(proc->name, make_string("main"))) {
			ssa_emit_startup_runtime(proc);
		}
	}
}


void ssa_build_proc(ssaValue *value, ssaProcedure *parent) {
	ssaProcedure *proc = &value->Proc;

	proc->parent = parent;

	if (proc->body != NULL) {
		ssa_begin_procedure_body(proc);
		ssa_insert_code_before_proc(proc, parent);
		ssa_build_stmt(proc, proc->body);
		ssa_end_procedure_body(proc);
	}
}