[202x][0004] Disallow ignored initializers

docs/ReleaseNotes.md

@@ -51,6 +51,9 @@ line upon naming the release. Refer to previous for appropriate section names.
 - HLSL 202x now supports variadic templates and template function parameter
   packs, pack expansions, and `sizeof...()`
   [#8905](https://github.com/microsoft/DirectXShaderCompiler/issues/8905).
+- HLSL 202x disallows initializers on variables in explicit and implicit
+  constant buffers and texture buffers
+  [#8483](https://github.com/microsoft/DirectXShaderCompiler/issues/8483).
 - HLSL 202x disallows putting cbuffer, tbuffer, or namespace declarations inside
   a cbuffer or tbuffer
   [#8484](https://github.com/microsoft/DirectXShaderCompiler/issues/8484).

tools/clang/include/clang/Basic/DiagnosticGroups.td

@@ -806,6 +806,9 @@ def HLSLParameterUsage : DiagGroup<"parameter-usage">;
 def HLSLAvailability: DiagGroup<"hlsl-availability">;
 def HLSLAvailabilityConstant: DiagGroup<"hlsl-availability-constant">;
 def HLSLBarrier : DiagGroup<"hlsl-barrier">;
+def HLSLBufferInitializer : DiagGroup<"hlsl-buffer-initializer">;
+def HLSLGroupSharedInitializer :
+    DiagGroup<"hlsl-groupshared-initializer">;
 
 // HLSL 2026 compatibility warnings: these warn on code in older language modes
 // that changes meaning or becomes illegal in HLSL 2026.

tools/clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -7575,6 +7575,14 @@ def err_hlsl_packoffset_requires_cbuffer : Error<
   "packoffset is only allowed in a constant buffer">;
 def warn_hlsl_packoffset_mix : Warning<
   "cannot mix packoffset elements with nonpackoffset elements in a cbuffer">;
+def warn_hlsl_buffer_initializer : Warning<
+  "initializer for a variable in a %select{tbuffer|cbuffer}0 will be ignored">,
+  InGroup<HLSLBufferInitializer>;
+def err_hlsl_buffer_initializer : Error<
+  "variable in a %select{tbuffer|cbuffer}0 cannot have an initializer">;
+def warn_hlsl_groupshared_initializer : Warning<
+  "initializer of 'groupshared' variable will be ignored">,
+  InGroup<HLSLGroupSharedInitializer>;
 def err_hlsl_packoffset_overlap : Error<"packoffset overlap between %0, %1">;
 def err_hlsl_register_semantics_conflicting : Error<
   "conflicting register semantics">;

tools/clang/lib/CodeGen/CodeGenModule.cpp

@@ -2109,12 +2109,6 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
         NeedsGlobalCtor = true;
         // HLSL Change Begins.
         if (getLangOpts().HLSL && D->isExternallyVisible()) {
-          // For global constant with init, the init will be ignored.
-          // Warning here.
-          unsigned DiagID = Diags.getCustomDiagID(
-              DiagnosticsEngine::Warning,
-              "Initializer of external global will be ignored");
-          Diags.Report(D->getLocation(), DiagID);
           // Don't create global ctor for it.
           NeedsGlobalCtor = false;
         }
@@ -2130,13 +2124,9 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
       if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
         DelayedCXXInitPosition.erase(D);
       // HLSL Change Begins.
-      if (getLangOpts().HLSL && D->isExternallyVisible() && !D->isStaticDataMember()) {
-        // For global constant with init, the init will be ignored.
+      if (getLangOpts().HLSL && D->isExternallyVisible() &&
+          !D->isStaticDataMember()) {
         Init = EmitNullConstant(D->getType());
-        unsigned DiagID = Diags.getCustomDiagID(
-            DiagnosticsEngine::Warning,
-            "Initializer of external global will be ignored");
-        Diags.Report(D->getLocation(), DiagID);
       }
       // HLSL Change Ends.
     }

tools/clang/lib/SPIRV/DeclResultIdMapper.cpp

@@ -1780,13 +1780,6 @@ void DeclResultIdMapper::createGlobalsCBuffer(const VarDecl *var) {
   uint32_t index = 0;
   for (const auto *decl : collectDeclsInDeclContext(context)) {
     if (const auto *varDecl = dyn_cast<VarDecl>(decl)) {
-      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 "
                   "vk::binding attribute",

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -1937,21 +1937,11 @@ void SpirvEmitter::registerCapabilitiesAndExtensionsForVarDecl(
 
 void SpirvEmitter::doHLSLBufferDecl(const HLSLBufferDecl *bufferDecl) {
   // This is a cbuffer/tbuffer decl.
-  // Check and emit warnings for member intializers which are not
-  // supported in Vulkan
   for (const auto *member : bufferDecl->decls()) {
     if (const auto *varMember = dyn_cast<VarDecl>(member)) {
       if (varMember->getStorageClass() == StorageClass::SC_Static)
         continue;
 
-      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 (isOrContainsNonFpColMajorMatrix(astContext, spirvOptions,
                                           varMember->getType(), varMember)) {
@@ -2199,10 +2189,6 @@ void SpirvEmitter::doVarDecl(const VarDecl *decl) {
   // variables) belongs to the Function storage class.
   if (isExternalVar(decl)) {
     var = declIdMapper.createExternVar(decl);
-    if (decl->hasInit()) {
-      emitWarning("Initializer of external global will be ignored",
-                  decl->getLocation());
-    }
   } else {
     // We already know the variable is not externally visible here. If it does
     // not have local storage, it should be file scope variable.

tools/clang/lib/Sema/SemaDecl.cpp

@@ -66,6 +66,28 @@ Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
 
 namespace {
 
+// HLSL Change Begin
+// Returns true if VD is a shader constant: a variable stored in an explicit
+// cbuffer/tbuffer declaration, or in the implicit $Globals constant buffer.
+// On success IsConstantBuffer is false only for tbuffer members.
+bool IsHLSLShaderConstant(const VarDecl *VD, bool &IsConstantBuffer) {
+  if (const auto *Buffer = dyn_cast<HLSLBufferDecl>(VD->getDeclContext())) {
+    IsConstantBuffer = Buffer->isCBuffer();
+    return VD->getStorageClass() != SC_Static;
+  }
+
+  IsConstantBuffer = true;
+  const DeclContext *DC = VD->getDeclContext();
+  return (DC->isTranslationUnit() || DC->isNamespace()) &&
+         VD->hasExternalFormalLinkage() &&
+         !VD->hasAttr<HLSLGroupSharedAttr>() &&
+         !VD->hasAttr<VKConstantIdAttr>() &&
+         !VD->hasAttr<VKPushConstantAttr>() &&
+         !VD->hasAttr<VKStorageClassExtAttr>() &&
+         hlsl::IsHLSLNumericOrAggregateOfNumericType(VD->getType());
+}
+// HLSL Change End
+
 class TypeNameValidatorCCC : public CorrectionCandidateCallback {
  public:
   TypeNameValidatorCCC(bool AllowInvalid, bool WantClass=false,
@@ -9334,6 +9356,28 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init,
   // Attach the initializer to the decl.
   VDecl->setInit(Init);
 
+  // HLSL Change Begin
+  if (getLangOpts().HLSL) {
+    if (VDecl->hasAttr<HLSLGroupSharedAttr>() &&
+        (getLangOpts().SPIRV || VDecl->isExternallyVisible())) {
+      Diag(Init->getExprLoc(), diag::warn_hlsl_groupshared_initializer)
+          << Init->getSourceRange();
+    } else {
+      // Variables in a cbuffer/tbuffer declaration, or in the implicit
+      // $Globals constant buffer, are initialized by the pipeline, so any
+      // initializer is ignored. This is an error starting with HLSL 202x.
+      bool IsConstantBuffer = false;
+      if (IsHLSLShaderConstant(VDecl, IsConstantBuffer)) {
+        Diag(Init->getExprLoc(),
+             getLangOpts().HLSLVersion >= hlsl::LangStd::v202x
+                 ? diag::err_hlsl_buffer_initializer
+                 : diag::warn_hlsl_buffer_initializer)
+            << IsConstantBuffer << Init->getSourceRange();
+      }
+    }
+  }
+  // HLSL Change End
+
   if (VDecl->isLocalVarDecl()) {
     // C99 6.7.8p4: All the expressions in an initializer for an object that has
     // static storage duration shall be constant expressions or string literals.

tools/clang/test/CodeGenSPIRV/groupshared.init.warning.hlsl

@@ -1,11 +1,15 @@
-// RUN: %dxc -T cs_6_0 -E main -spirv %s 2>&1 | FileCheck %s
+// RUN: %dxc -T cs_6_0 -E main -spirv -verify %s
 
 groupshared uint testing = 0;
+// expected-warning@-1 {{initializer of 'groupshared' variable will be ignored}}
+
+static groupshared uint staticTesting = 1;
+// expected-warning@-1 {{initializer of 'groupshared' variable will be ignored}}
 
 [numthreads(64, 1, 1)]
 void main(uint local_thread_id_flat : SV_GroupIndex) {
 
-    InterlockedAdd(testing, 1);
+    InterlockedAdd(testing, staticTesting);
     GroupMemoryBarrierWithGroupSync();
 
     if (local_thread_id_flat == 0) {
@@ -14,6 +18,3 @@ void main(uint local_thread_id_flat : SV_GroupIndex) {
         }
     }
 }
-
-// CHECK: warning: Initializer of external global will be ignored
-// CHECK-NEXT: groupshared uint testing = 0;

tools/clang/test/CodeGenSPIRV/implicit.global.ubo.hlsl

@@ -1,4 +1,5 @@
-// RUN: %dxc -T ps_6_0 -E main %s -spirv | FileCheck %s
+// RUN: %dxc -T ps_6_0 -E main -Werror %s -spirv | FileCheck %s
+// RUN: %dxc -T ps_6_0 -E main -HV 202x %s -spirv | FileCheck %s
 
 // This test checks that the specialization constant and push constants are not
 // included in the implicit global ubo.

tools/clang/test/CodeGenSPIRV/var.globals.error.hlsl

@@ -1,8 +1,9 @@
 // RUN: not %dxc -T vs_6_0 -E main -fcgl  %s -spirv  2>&1 | FileCheck %s
-
+// Note: this test uses FileCheck instead of -verify because the error
+// diagnostic comes from the code generation layer instead of sema.
 [[vk::binding(10, 2)]] float4 gVec = 1.0;
 
 float4 main() : A { return gVec; }
 
-// CHECK: :3:38: warning: variable 'gVec' will be placed in $Globals so initializer ignored
-// CHECK: :3:3: error: variable 'gVec' will be placed in $Globals so cannot have vk::binding attribute
+// CHECK: :4:38: warning: initializer for a variable in a cbuffer will be ignored
+// CHECK: :4:3: error: variable 'gVec' will be placed in $Globals so cannot have vk::binding attribute

tools/clang/test/CodeGenSPIRV/var.init.cbuffer.hlsl

@@ -1,13 +1,10 @@
-// RUN: %dxc -T vs_6_0 -E main -fcgl  %s -spirv  2>&1 | FileCheck %s
+// RUN: %dxc -T vs_6_0 -E main -verify %s -spirv
 
 cbuffer MyCBuffer {
-    float a = 1.0;
-    float4 b = 2.0;
+    float a = 1.0; // expected-warning{{initializer for a variable in a cbuffer will be ignored}}
+    float4 b = 2.0; // expected-warning{{initializer for a variable in a cbuffer will be ignored}}
 };
 
 float main() : A {
     return 1.0;
 }
-
-// CHECK: :4:15: warning: cbuffer member initializer ignored since no Vulkan equivalent
-// CHECK: :5:16: warning: cbuffer member initializer ignored since no Vulkan equivalent

tools/clang/test/CodeGenSPIRV/var.init.tbuffer.hlsl

@@ -1,13 +1,10 @@
-// RUN: %dxc -T vs_6_0 -E main -fcgl  %s -spirv  2>&1 | FileCheck %s
+// RUN: %dxc -T vs_6_0 -E main -verify %s -spirv
 
 tbuffer MyTBuffer {
-    float a = 1.0;
-    float4 b = 2.0;
+    float a = 1.0; //expected-warning{{initializer for a variable in a tbuffer will be ignored}}
+    float4 b = 2.0; //expected-warning{{initializer for a variable in a tbuffer will be ignored}}
 };
 
 float main() : A {
     return 1.0;
 }
-
-// CHECK: :4:15: warning: tbuffer member initializer ignored since no Vulkan equivalent
-// CHECK: :5:16: warning: tbuffer member initializer ignored since no Vulkan equivalent

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

@@ -1,4 +1,4 @@
-// RUN: %dxc -T vs_6_0 -E main -Wno-vk-ignored-features -fcgl  %s -spirv  2>&1 | FileCheck %s
+// RUN: %dxc -T vs_6_0 -E main -Wno-vk-ignored-features -Wno-hlsl-buffer-initializer -fcgl  %s -spirv  2>&1 | FileCheck %s
 
 cbuffer MyCBuffer {
     float a = 1.0;

tools/clang/test/HLSL/cpp-errors-hv2015.hlsl

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -HV 2015 -fsyntax-only -Wno-unused-value -ffreestanding -verify %s
+// RUN: %clang_cc1 -Wno-hlsl-buffer-initializer -HV 2015 -fsyntax-only -Wno-unused-value -ffreestanding -verify %s
 
 float f_arr_empty_init[] = { 1, 2, 3 };
 float f_arr_empty_pack[] = { 1, 2 ... }; // expected-error {{expansion is unsupported in HLSL}}

tools/clang/test/HLSL/cpp-errors.hlsl

@@ -1,18 +1,18 @@
 // RUN: %clang_cc1 -fsyntax-only -Wno-unused-value -ffreestanding -HV 2018 -verify %s
 
-float f_arr_empty_init[] = { 1, 2, 3 };
+float f_arr_empty_init[] = { 1, 2, 3 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 float f_arr_empty_pack[] = { 1, 2 ... }; // expected-error {{expansion is unsupported in HLSL}}
 
 struct s_arr_i_f { int i; float f; };
-s_arr_i_f arr_struct_none[] = { }; // TODO: this should fail - see comments in HLSLExternalSource::InitializeInitSequenceForHLSL
-s_arr_i_f arr_struct_one[] = { 1, 2 };
+s_arr_i_f arr_struct_none[] = { }; // TODO: this should fail - see comments in HLSLExternalSource::InitializeInitSequenceForHLSL    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
+s_arr_i_f arr_struct_one[] = { 1, 2 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 s_arr_i_f arr_struct_incomplete[] = { 1, 2, 3 }; // expected-error {{too few elements in vector initialization (expected 4 elements, have 3)}}
-s_arr_i_f arr_struct_two[] = { 1, 2, 3, 4 };
+s_arr_i_f arr_struct_two[] = { 1, 2, 3, 4 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 
 int g_int;
 typeof(g_int) g_typeof_int; // expected-error {{HLSL requires a type specifier for all declarations}} expected-error {{expected ';' after top level declarator}} expected-error {{unknown type name 'typeof'; did you mean 'typedef'?}}
 typedef int (*fn_int)(int); // expected-error {{pointers are unsupported in HLSL}}
-auto g_auto = 3; // auto is now supported in HLSL via type deduction; no error expected
+auto g_auto = 3; // auto is now supported in HLSL via type deduction; no error expected    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 __is_signed g_is_signed; // expected-error {{'__is_signed' is a reserved keyword in HLSL}} expected-error {{HLSL requires a type specifier for all declarations}}
 register int g_register; // expected-error {{'register' is a reserved keyword in HLSL}}
 __thread int g_thread; // expected-error {{'__thread' is a reserved keyword in HLSL}}
@@ -321,7 +321,7 @@ struct forward_struct; // this fails in fxc, but we allow it now
 struct my_struct_type_decl { int a; } my_struct_var_decl;
 struct my_struct_type_decl_parens { int a; } (my_struct_var_decl_parens); // expected-error {{HLSL requires a type specifier for all declarations}} expected-error {{expected ';' after struct}}
 struct my_struct_type_const { int a; } const my_struct_type_var; // // expected-error {{HLSL requires a type specifier for all declarations}} expected-error {{expected ';' after struct}}
-struct my_struct_type_init { int a; } my_struct_type_init_one = { 1 }, my_struct_type_init_two = { 2 };
+struct my_struct_type_init { int a; } my_struct_type_init_one = { 1 }, my_struct_type_init_two = { 2 };    /* expected-warning 2 {{initializer for a variable in a cbuffer will be ignored}} */
 struct my_struct_type_static { int a; } static my_struct_type_static; // expected-error {{expected ';' after struct}} expected-warning {{declaration does not declare anything}}
 struct { int my_anon_struct_field; } my_anon_struct_type;
 

tools/clang/test/HLSL/rewriter/cpp-errors_noerr.hlsl

@@ -1,13 +1,13 @@
 // RUN: %clang_cc1 -fsyntax-only -Wno-unused-value -ffreestanding -verify %s
 
-float f_arr_empty_init[] = { 1, 2, 3 };
+float f_arr_empty_init[] = { 1, 2, 3 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 //float f_arr_empty_pack[] = { 1, 2 ... }; // expected-error {{expansion is unsupported in HLSL}}
 
 struct s_arr_i_f { int i; float f; };
-s_arr_i_f arr_struct_none[] = { }; // TODO: this should fail - see comments in HLSLExternalSource::InitializeInitSequenceForHLSL
-s_arr_i_f arr_struct_one[] = { 1, 2 };
+s_arr_i_f arr_struct_none[] = { }; // TODO: this should fail - see comments in HLSLExternalSource::InitializeInitSequenceForHLSL    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
+s_arr_i_f arr_struct_one[] = { 1, 2 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 //s_arr_i_f arr_struct_incomplete[] = { 1, 2, 3 }; // expected-error {{too few elements in vector initialization (expected 4 elements, have 3)}}
-s_arr_i_f arr_struct_two[] = { 1, 2, 3, 4 };
+s_arr_i_f arr_struct_two[] = { 1, 2, 3, 4 };    /* expected-warning {{initializer for a variable in a cbuffer will be ignored}} */
 
 int g_int;
 //typeof(g_int) g_typeof_int; // expected-error {{unknown type name 'typeof'; did you mean 'typedef'?}} expected-error {{HLSL requires a type specifier for all declarations}} expected-error {{expected ';' after top level declarator}}
@@ -332,7 +332,7 @@ struct my_struct_5 : my_class, my_interface { };
 struct my_struct_type_decl { int a; } my_struct_var_decl;
 //struct my_struct_type_decl_parens { int a; } (my_struct_var_decl_parens); // expected-error {{expected ';' after struct}} expected-error {{HLSL requires a type specifier for all declarations}}
 //struct my_struct_type_const { int a; } const my_struct_type_var; // // expected-error {{expected ';' after struct}} expected-error {{HLSL requires a type specifier for all declarations}}
-struct my_struct_type_init { int a; } my_struct_type_init_one = { 1 }, my_struct_type_init_two = { 2 };
+struct my_struct_type_init { int a; } my_struct_type_init_one = { 1 }, my_struct_type_init_two = { 2 };    /* expected-warning 2 {{initializer for a variable in a cbuffer will be ignored}} */
 //struct my_struct_type_static { int a; } static my_struct_type_static; // expected-error {{expected ';' after struct}} expected-warning {{declaration does not declare anything}}
 struct { int my_anon_struct_field; } my_anon_struct_type;