[spirv] Add option to ignore warnings on features without Vulkan support (#1289)

Added -Wno-vk-ignored-features to suppress warnings on features
that are ignored because of no Vulkan support. Examples include
cbuffer member initializer.

docs/SPIR-V.rst

@@ -2711,6 +2711,8 @@ codegen for Vulkan:
 - ``-fspv-target-env=<env>``: Specifies the target environment for this compilation.
   The current valid options are ``vulkan1.0`` and ``vulkan1.1``. If no target
   environment is provided, ``vulkan1.0`` is used as default.
+- ``-Wno-vk-ignored-features``: Does not emit warnings on ignored features
+  resulting from no Vulkan support, e.g., cbuffer member initializer.
 
 Unsupported HLSL Features
 =========================

include/dxc/Support/HLSLOptions.h

@@ -165,6 +165,7 @@ public:
   bool VkUseGlLayout;                      // OPT_fvk_use_gl_layout
   bool VkUseDxLayout;                      // OPT_fvk_use_dx_layout
   bool SpvEnableReflect;                   // OPT_fspv_reflect
+  bool VkNoWarnIgnoredFeatures;            // OPT_Wno_vk_ignored_features
   llvm::StringRef VkStageIoOrder;          // OPT_fvk_stage_io_order
   llvm::SmallVector<int32_t, 4> VkBShift;  // OPT_fvk_b_shift
   llvm::SmallVector<int32_t, 4> VkTShift;  // OPT_fvk_t_shift

include/dxc/Support/HLSLOptions.td

@@ -258,6 +258,8 @@ def fspv_extension_EQ : Joined<["-"], "fspv-extension=">, Group<spirv_Group>, Fl
   HelpText<"Specify SPIR-V extension permitted to use">;
 def fspv_target_env_EQ : Joined<["-"], "fspv-target-env=">, Group<spirv_Group>, Flags<[CoreOption, DriverOption]>,
   HelpText<"Specify the target environment: vulkan1.0 (default) or vulkan1.1">;
+def Wno_vk_ignored_features : Joined<["-"], "Wno-vk-ignored-features">, Group<spirv_Group>, Flags<[CoreOption, DriverOption, HelpHidden]>,
+  HelpText<"Do not emit warnings for ingored features resulting from no Vulkan support">;
 // SPIRV Change Ends
 
 //////////////////////////////////////////////////////////////////////////////

lib/DxcSupport/HLSLOptions.cpp

@@ -489,6 +489,7 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
   opts.VkUseGlLayout = Args.hasFlag(OPT_fvk_use_gl_layout, OPT_INVALID, false);
   opts.VkUseDxLayout = Args.hasFlag(OPT_fvk_use_dx_layout, OPT_INVALID, false);
   opts.SpvEnableReflect = Args.hasFlag(OPT_fspv_reflect, OPT_INVALID, false);
+  opts.VkNoWarnIgnoredFeatures = Args.hasFlag(OPT_Wno_vk_ignored_features, OPT_INVALID, false);
 
   // Collects the arguments for -fvk-{b|s|t|u}-shift.
   const auto handleVkShiftArgs =
@@ -553,6 +554,7 @@ int ReadDxcOpts(const OptTable *optionTable, unsigned flagsToInclude,
       Args.hasFlag(OPT_fvk_use_gl_layout, OPT_INVALID, false) ||
       Args.hasFlag(OPT_fvk_use_dx_layout, OPT_INVALID, false) ||
       Args.hasFlag(OPT_fspv_reflect, OPT_INVALID, false) ||
+      Args.hasFlag(OPT_Wno_vk_ignored_features, OPT_INVALID, false) ||
       !Args.getLastArgValue(OPT_fvk_stage_io_order_EQ).empty() ||
       !Args.getLastArgValue(OPT_fspv_extension_EQ).empty() ||
       !Args.getLastArgValue(OPT_fspv_target_env_EQ).empty() ||

tools/clang/include/clang/SPIRV/EmitSPIRVOptions.h

@@ -38,6 +38,7 @@ struct EmitSPIRVOptions {
   bool enable16BitTypes;
   bool enableReflect;
   bool enableDebugInfo;
+  bool noWarnIgnoredFeatures;
   llvm::StringRef stageIoOrder;
   llvm::SmallVector<int32_t, 4> bShift;
   llvm::SmallVector<int32_t, 4> tShift;

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -679,11 +679,12 @@ void DeclResultIdMapper::createGlobalsCBuffer(const VarDecl *var) {
   uint32_t index = 0;
   for (const auto *decl : typeTranslator.collectDeclsInDeclContext(context))
     if (const auto *varDecl = dyn_cast<VarDecl>(decl)) {
-      if (const auto *init = varDecl->getInit()) {
-        emitWarning(
-            "variable '%0' will be placed in $Globals so initializer ignored",
-            init->getExprLoc())
-            << var->getName() << init->getSourceRange();
+      if (!spirvOptions.noWarnIgnoredFeatures) {
+        if (const auto *init = varDecl->getInit())
+          emitWarning(
+              "variable '%0' will be placed in $Globals so initializer ignored",
+              init->getExprLoc())
+              << var->getName() << init->getSourceRange();
       }
       if (const auto *attr = varDecl->getAttr<VKBindingAttr>()) {
         emitError("variable '%0' will be placed in $Globals so cannot have "

tools/clang/lib/SPIRV/SPIRVEmitter.cpp

@@ -1213,11 +1213,13 @@ void SPIRVEmitter::doHLSLBufferDecl(const HLSLBufferDecl *bufferDecl) {
   // supported in Vulkan
   for (const auto *member : bufferDecl->decls()) {
     if (const auto *varMember = dyn_cast<VarDecl>(member)) {
-      if (const auto *init = varMember->getInit())
-        emitWarning("%select{tbuffer|cbuffer}0 member initializer "
-                    "ignored since no Vulkan equivalent",
-                    init->getExprLoc())
-            << bufferDecl->isCBuffer() << init->getSourceRange();
+      if (!spirvOptions.noWarnIgnoredFeatures) {
+        if (const auto *init = varMember->getInit())
+          emitWarning("%select{tbuffer|cbuffer}0 member initializer "
+                      "ignored since no Vulkan equivalent",
+                      init->getExprLoc())
+              << bufferDecl->isCBuffer() << init->getSourceRange();
+      }
 
       // We cannot handle external initialization of column-major matrices now.
       if (typeTranslator.isOrContainsNonFpColMajorMatrix(varMember->getType(),

tools/clang/test/CodeGenSPIRV/var.init.warning.ignored.hlsl

@@ -0,0 +1,16 @@
+// Run: %dxc -T vs_6_0 -E main -Wno-vk-ignored-features
+
+cbuffer MyCBuffer {
+    float a = 1.0;
+    float4 b = 2.0;
+};
+
+float gFloat = 3.0;
+
+float main() : A {
+    return float4(1, 2, 3, 4); // float4 -> float will trigger a warning
+}
+
+// CHECK-NOT: initializer
+// CHECK: warning: implicit truncation of vector type
+// CHECK-NOT: initializer

tools/clang/tools/dxcompiler/dxcompilerobj.cpp

@@ -474,6 +474,7 @@ public:
           spirvOpts.enableReflect = opts.SpvEnableReflect;
           spirvOpts.defaultRowMajor = opts.DefaultRowMajor;
           spirvOpts.stageIoOrder = opts.VkStageIoOrder;
+          spirvOpts.noWarnIgnoredFeatures = opts.VkNoWarnIgnoredFeatures;
           spirvOpts.bShift = opts.VkBShift;
           spirvOpts.tShift = opts.VkTShift;
           spirvOpts.sShift = opts.VkSShift;

tools/clang/unittests/SPIRV/CodeGenSPIRVTest.cpp

@@ -120,6 +120,9 @@ TEST_F(FileTest, VarInitCbuffer) {
 TEST_F(FileTest, VarInitTbuffer) {
   runFileTest("var.init.tbuffer.hlsl", Expect::Warning);
 }
+TEST_F(FileTest, VarInitWarningIngored) {
+  runFileTest("var.init.warning.ignored.hlsl", Expect::Warning);
+}
 TEST_F(FileTest, VarInitOpaque) { runFileTest("var.init.opaque.hlsl"); }
 TEST_F(FileTest, VarInitCrossStorageClass) {
   runFileTest("var.init.cross-storage-class.hlsl");