[SPIRV] Generate DebugFunctionDefinition in real function instead of wrapper (microsoft#6758)

This PR moves the DebugFunctionDefinition instruction from the SPIR-V
wrapper to the real function. This supplies debugger users with greater
accuracy.

Author: SteveUrquhart

tools/clang/lib/SPIRV/SpirvEmitter.cpp

@@ -1462,7 +1462,7 @@ void SpirvEmitter::doFunctionDecl(const FunctionDecl *decl) {
       isEntry = true;
       funcName = "src." + funcName;
       // Create wrapper for the entry function
-      if (!emitEntryFunctionWrapper(decl, func, debugFunction))
+      if (!emitEntryFunctionWrapper(decl, func))
         return;
       // Generate DebugEntryPoint if function definition
       if (spirvOptions.debugInfoVulkan && debugFunction) {
@@ -1531,8 +1531,7 @@ void SpirvEmitter::doFunctionDecl(const FunctionDecl *decl) {
 
     // Add DebugFunctionDefinition if we are emitting
     // NonSemantic.Shader.DebugInfo.100 debug info
-    // and we haven't already added it to the wrapper.
-    if (!isEntry && spirvOptions.debugInfoVulkan && debugFunction)
+    if (spirvOptions.debugInfoVulkan && debugFunction)
       spvBuilder.createDebugFunctionDef(debugFunction, func);
 
     // Process all statments in the body.
@@ -13017,19 +13016,11 @@ bool SpirvEmitter::processTessellationShaderAttributes(
 }
 
 bool SpirvEmitter::emitEntryFunctionWrapperForRayTracing(
-    const FunctionDecl *decl, SpirvFunction *entryFuncInstr,
-    SpirvDebugFunction *debugFunction) {
+    const FunctionDecl *decl, SpirvFunction *entryFuncInstr) {
   // The entry basic block.
   auto *entryLabel = spvBuilder.createBasicBlock();
   spvBuilder.setInsertPoint(entryLabel);
 
-  // Add DebugFunctionDefinition if we are emitting
-  // NonSemantic.Shader.DebugInfo.100 debug info.
-  // We will emit it in the wrapper rather than the
-  // user function.
-  if (spirvOptions.debugInfoVulkan && debugFunction)
-    spvBuilder.createDebugFunctionDef(debugFunction, entryFunction);
-
   // Initialize all global variables at the beginning of the wrapper
   for (const VarDecl *varDecl : toInitGloalVars) {
     const auto varInfo =
@@ -13293,8 +13284,7 @@ bool SpirvEmitter::processMeshOrAmplificationShaderAttributes(
 }
 
 bool SpirvEmitter::emitEntryFunctionWrapper(const FunctionDecl *decl,
-                                            SpirvFunction *entryFuncInstr,
-                                            SpirvDebugFunction *debugFunction) {
+                                            SpirvFunction *entryFuncInstr) {
   // HS specific attributes
   uint32_t numOutputControlPoints = 0;
   SpirvInstruction *outputControlPointIdVal =
@@ -13329,8 +13319,7 @@ bool SpirvEmitter::emitEntryFunctionWrapper(const FunctionDecl *decl,
   entryInfo->entryFunction = entryFunction;
 
   if (spvContext.isRay()) {
-    return emitEntryFunctionWrapperForRayTracing(decl, entryFuncInstr,
-                                                 debugFunction);
+    return emitEntryFunctionWrapperForRayTracing(decl, entryFuncInstr);
   }
   // Handle attributes specific to each shader stage
   if (spvContext.isPS()) {
@@ -13411,13 +13400,6 @@ bool SpirvEmitter::emitEntryFunctionWrapper(const FunctionDecl *decl,
   // after the basic block is created and insert point is set.
   processInlineSpirvAttributes(decl);
 
-  // Add DebugFunctionDefinition if we are emitting
-  // NonSemantic.Shader.DebugInfo.100 debug info.
-  // We will emit it in the wrapper rather than the
-  // user function.
-  if (spirvOptions.debugInfoVulkan && debugFunction)
-    spvBuilder.createDebugFunctionDef(debugFunction, entryFunction);
-
   // Initialize all global variables at the beginning of the wrapper
   for (const VarDecl *varDecl : toInitGloalVars) {
     // SPIR-V does not have string variables

tools/clang/lib/SPIRV/SpirvEmitter.h

@@ -848,8 +848,7 @@ class SpirvEmitter : public ASTConsumer {
   /// The wrapper function is also responsible for initializing global static
   /// variables for some cases.
   bool emitEntryFunctionWrapper(const FunctionDecl *entryFunction,
-                                SpirvFunction *entryFuncId,
-                                SpirvDebugFunction *debugFunction);
+                                SpirvFunction *entryFuncId);
 
   /// \brief Emits a wrapper function for the entry functions for raytracing
   /// stages and returns true on success.
@@ -859,8 +858,7 @@ class SpirvEmitter : public ASTConsumer {
   /// The wrapper function is also responsible for initializing global static
   /// variables for some cases.
   bool emitEntryFunctionWrapperForRayTracing(const FunctionDecl *entryFunction,
-                                             SpirvFunction *entryFuncId,
-                                             SpirvDebugFunction *debugFunction);
+                                             SpirvFunction *entryFuncId);
 
   /// \brief Performs the following operations for the Hull shader:
   /// * Creates an output variable which is an Array containing results for all

tools/clang/test/CodeGenSPIRV/shader.debug.function.hlsl

@@ -17,18 +17,17 @@
 
 // Check DebugFunction instructions
 //
-// CHECK: {{%[0-9]+}} = OpExtInst %void [[set]] DebugFunction [[fooName]] [[fooFnType]] [[source]] %uint_35 %uint_1 [[compilationUnit]] [[emptyStr]] %uint_3 %uint_36
+// CHECK: {{%[0-9]+}} = OpExtInst %void [[set]] DebugFunction [[fooName]] [[fooFnType]] [[source]] %uint_34 %uint_1 [[compilationUnit]] [[emptyStr]] %uint_3 %uint_35
 
 // CHECK: [[float4:%[0-9]+]] = OpExtInst %void [[set]] DebugTypeVector [[float]] %uint_4
 // CHECK: [[mainFnType:%[0-9]+]] = OpExtInst %void [[set]] DebugTypeFunction %uint_3 [[float4]] [[float4]]
-// CHECK: [[mainDbgFn:%[0-9]+]] = OpExtInst %void [[set]] DebugFunction [[mainName]] [[mainFnType]] [[source]] %uint_40 %uint_1 [[compilationUnit]] [[emptyStr]] %uint_3 %uint_41 
+// CHECK: [[mainDbgFn:%[0-9]+]] = OpExtInst %void [[set]] DebugFunction [[mainName]] [[mainFnType]] [[source]] %uint_39 %uint_1 [[compilationUnit]] [[emptyStr]] %uint_3 %uint_40 
 // CHECK: [[mainDbgEp:%[0-9]+]] = OpExtInst %void [[set]] DebugEntryPoint [[mainDbgFn]] [[compilationUnit]] {{%[0-9]+}} [[clOpts]]
 
-// Check DebugFunctionDefintion is in main
+// Check DebugFunctionDefintion is in src_main
 //
-// CHECK: %main = OpFunction %void None {{%[0-9]+}}
-// CHECK: {{%[0-9]+}} = OpExtInst %void [[set]] DebugFunctionDefinition [[mainDbgFn]] %main
-// CHECK: OpFunctionEnd
+// CHECK: %src_main = OpFunction %v4float None {{%[0-9]+}}
+// CHECK: {{%[0-9]+}} = OpExtInst %void [[set]] DebugFunctionDefinition [[mainDbgFn]] %src_main
 // CHECK: OpFunctionEnd
 // CHECK: OpFunctionEnd