[DebugInfo] Preserve DIExpression in DIGlobalVariableExpression (#2285)

Preserve DIExpression in DIGlobalVariableExpression.

Preserving DIExpressions is necessary because of this change in LLVM:

commit 638a8393615e911b729d5662096f60ef49f1c65e
Author: Michael Buch [email protected]
Date: Mon Nov 13 06:04:27 2023 +0000

Reland "[clang][DebugInfo] Emit global variable definitions for static data members with constant initializers" (#71780)

Author: LU-JOHN

lib/SPIRV/LLVMToSPIRVDbgTran.cpp

@@ -1185,6 +1185,23 @@ LLVMToSPIRVDbgTran::transDbgGlobalVariable(const DIGlobalVariable *GV) {
   if (DIDerivedType *StaticMember = GV->getStaticDataMemberDeclaration())
     Ops.push_back(transDbgEntry(StaticMember)->getId());
 
+  // Check if Ops[VariableIdx] has no information
+  if (Ops[VariableIdx] == getDebugInfoNoneId()) {
+    // Check if GV has an associated GVE with a non-empty DIExpression.
+    // The non-empty DIExpression gives the initial value of the GV.
+    for (const DIGlobalVariableExpression *GVE : DIF.global_variables()) {
+      if ( // GVE matches GV
+          GVE->getVariable() == GV &&
+          // DIExpression is non-empty
+          GVE->getExpression()->getNumElements()) {
+        // Repurpose VariableIdx operand to hold the initial value held in the
+        // GVE's DIExpression
+        Ops[VariableIdx] = transDbgExpression(GVE->getExpression())->getId();
+        break;
+      }
+    }
+  }
+
   if (isNonSemanticDebugInfo())
     transformToConstant(Ops, {LineIdx, ColumnIdx, FlagsIdx});
   return BM->addDebugInfo(SPIRVDebug::GlobalVariable, getVoidTy(), Ops);

lib/SPIRV/SPIRVToLLVMDbgTran.cpp

@@ -1128,6 +1128,15 @@ MDNode *SPIRVToLLVMDbgTran::transGlobalVariable(const SPIRVExtInst *DebugInst) {
     StaticMemberDecl = transDebugInst<DIDerivedType>(
         BM->get<SPIRVExtInst>(Ops[StaticMemberDeclarationIdx]));
   }
+
+  DIExpression *DIExpr = nullptr;
+  // Check if Ops[VariableIdx] is not being used to hold a variable operand.
+  // Instead it is being used to hold an Expression that holds the initial
+  // value of the GlobalVariable.
+  if (getDbgInst<SPIRVDebug::Expression>(Ops[VariableIdx]))
+    DIExpr =
+        transDebugInst<DIExpression>(BM->get<SPIRVExtInst>(Ops[VariableIdx]));
+
   SPIRVWord Flags =
       getConstantValueOrLiteral(Ops, FlagsIdx, DebugInst->getExtSetKind());
   bool IsLocal = Flags & SPIRVDebug::FlagIsLocal;
@@ -1136,7 +1145,7 @@ MDNode *SPIRVToLLVMDbgTran::transGlobalVariable(const SPIRVExtInst *DebugInst) {
   if (IsDefinition) {
     VarDecl = getDIBuilder(DebugInst).createGlobalVariableExpression(
         Parent, Name, LinkageName, File, LineNo, Ty, IsLocal, IsDefinition,
-        nullptr, StaticMemberDecl);
+        DIExpr, StaticMemberDecl);
   } else {
     VarDecl = getDIBuilder(DebugInst).createTempGlobalVariableFwdDecl(
         Parent, Name, LinkageName, File, LineNo, Ty, IsLocal, StaticMemberDecl);
@@ -1145,15 +1154,20 @@ MDNode *SPIRVToLLVMDbgTran::transGlobalVariable(const SPIRVExtInst *DebugInst) {
     llvm::TempMDNode TMP(VarDecl);
     VarDecl = getDIBuilder(DebugInst).replaceTemporary(std::move(TMP), VarDecl);
   }
-  // If the variable has no initializer Ops[VariableIdx] is OpDebugInfoNone.
-  // Otherwise Ops[VariableIdx] may be a global variable or a constant(C++
-  // static const).
-  if (VarDecl && !getDbgInst<SPIRVDebug::DebugInfoNone>(Ops[VariableIdx])) {
-    SPIRVValue *V = BM->get<SPIRVValue>(Ops[VariableIdx]);
-    Value *Var = SPIRVReader->transValue(V, nullptr, nullptr);
-    llvm::GlobalVariable *GV = dyn_cast_or_null<llvm::GlobalVariable>(Var);
-    if (GV && !GV->hasMetadata("dbg"))
-      GV->addMetadata("dbg", *VarDecl);
+
+  // Ops[VariableIdx] was not used to hold an Expression with the initial value
+  // for the GlobalVariable
+  if (!DIExpr) {
+    // If the variable has no initializer Ops[VariableIdx] is OpDebugInfoNone.
+    // Otherwise Ops[VariableIdx] may be a global variable or a constant(C++
+    // static const).
+    if (VarDecl && !getDbgInst<SPIRVDebug::DebugInfoNone>(Ops[VariableIdx])) {
+      SPIRVValue *V = BM->get<SPIRVValue>(Ops[VariableIdx]);
+      Value *Var = SPIRVReader->transValue(V, nullptr, nullptr);
+      llvm::GlobalVariable *GV = dyn_cast_or_null<llvm::GlobalVariable>(Var);
+      if (GV && !GV->hasMetadata("dbg"))
+        GV->addMetadata("dbg", *VarDecl);
+    }
   }
   return VarDecl;
 }

test/DebugInfo/DebugInfo-GV-with-DIE.ll

@@ -0,0 +1,38 @@
+;; Ensure that DIExpressions are preserved in DIGlobalVariableExpressions
+;; This utilizes SPIRV DebugGlobalVariable's Variable field to hold the
+;; DIExpression.
+
+; RUN: llvm-as %s -o %t.bc
+
+; RUN: llvm-spirv -o %t.100.spt %t.bc --spirv-debug-info-version=nonsemantic-shader-100 -spirv-text
+; RUN: FileCheck %s --input-file %t.100.spt --check-prefix CHECK-SPIRV
+; RUN: llvm-spirv -o %t.100.spv %t.bc --spirv-debug-info-version=nonsemantic-shader-100
+; RUN: llvm-spirv -r -o %t.100.rev.bc %t.100.spv
+; RUN: llvm-dis %t.100.rev.bc -o %t.100.rev.ll
+; RUN: FileCheck %s --input-file %t.100.rev.ll --check-prefix CHECK-LLVM
+
+; RUN: llvm-spirv -o %t.200.spt %t.bc --spirv-debug-info-version=nonsemantic-shader-200 -spirv-text
+; RUN: FileCheck %s --input-file %t.200.spt --check-prefix CHECK-SPIRV
+; RUN: llvm-spirv -o %t.200.spv %t.bc --spirv-debug-info-version=nonsemantic-shader-200
+; RUN: llvm-spirv -r -o %t.200.rev.bc %t.200.spv
+; RUN: llvm-dis %t.200.rev.bc -o %t.200.rev.ll
+; RUN: FileCheck %s --input-file %t.200.rev.ll --check-prefix CHECK-LLVM
+
+; CHECK-SPIRV: [[EXPRESSION:[0-9]+]] [[#]] DebugExpression [[#]] [[#]]
+; CHECK-SPIRV: [[#]] [[#]] DebugGlobalVariable [[#]] [[#]] [[#]] [[#]] [[#]] [[#]] [[#]] [[EXPRESSION]] [[#]] {{$}}
+
+; CHECK-LLVM: ![[#]] = !DIGlobalVariableExpression(var: ![[#GV:]], expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+; CHECK-LLVM: ![[#GV]] = distinct !DIGlobalVariable(name: "true", scope: ![[#]], file: ![[#]], line: 3777, type: ![[#]], isLocal: true, isDefinition: true)
+
+!llvm.module.flags = !{!0, !1}
+!llvm.dbg.cu = !{!2}
+
+!0 = !{i32 7, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang", emissionKind: FullDebug, globals: !4)
+!3 = !DIFile(filename: "test.cpp", directory: "/path/to")
+!4 = !{!5}
+!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+!6 = distinct !DIGlobalVariable(name: "true", scope: !2, file: !3, line: 3777, type: !7, isLocal: true, isDefinition: true)
+!7 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8)
+!8 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)

test/DebugInfo/DebugInfo-GV-with-SMD-and-DIE.ll

@@ -0,0 +1,56 @@
+;; Ensure that DIExpressions are preserved in DIGlobalVariableExpressions
+;; when a Static Member Declaration is also needed.
+;; This utilizes SPIRV DebugGlobalVariable's Variable field to hold the
+;; DIExpression.
+
+;; Declaration generated from:
+;;
+;; struct A {
+;;   static int fully_specified;
+;; };
+;;  
+;; int A::fully_specified;
+
+; RUN: llvm-as %s -o %t.bc
+
+; RUN: llvm-spirv -o %t.100.spt %t.bc --spirv-debug-info-version=nonsemantic-shader-100 -spirv-text
+; RUN: FileCheck %s --input-file %t.100.spt --check-prefix CHECK-SPIRV
+; RUN: llvm-spirv -o %t.100.spv %t.bc --spirv-debug-info-version=nonsemantic-shader-100
+; RUN: llvm-spirv -r -o %t.100.rev.bc %t.100.spv
+; RUN: llvm-dis %t.100.rev.bc -o %t.100.rev.ll
+; RUN: FileCheck %s --input-file %t.100.rev.ll --check-prefix CHECK-LLVM
+
+; RUN: llvm-spirv -o %t.200.spt %t.bc --spirv-debug-info-version=nonsemantic-shader-200 -spirv-text
+; RUN: FileCheck %s --input-file %t.200.spt --check-prefix CHECK-SPIRV
+; RUN: llvm-spirv -o %t.200.spv %t.bc --spirv-debug-info-version=nonsemantic-shader-200
+; RUN: llvm-spirv -r -o %t.200.rev.bc %t.200.spv
+; RUN: llvm-dis %t.200.rev.bc -o %t.200.rev.ll
+; RUN: FileCheck %s --input-file %t.200.rev.ll --check-prefix CHECK-LLVM
+
+; CHECK-SPIRV-DAG: [[TYPE_MEMBER:[0-9]+]] [[#]] DebugTypeMember [[#]] [[#]] [[#]] [[#]]
+; CHECK-SPIRV-DAG: [[EXPRESSION:[0-9]+]] [[#]] DebugExpression [[#]] [[#]]
+; CHECK-SPIRV: [[#]] [[#]] DebugGlobalVariable [[#]] [[#]] [[#]] [[#]] [[#]] [[#]] [[#]] [[EXPRESSION]] [[#]] [[TYPE_MEMBER]] {{$}}
+
+; CHECK-LLVM: ![[#]] = !DIGlobalVariableExpression(var: ![[#GV:]], expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+; CHECK-LLVM: ![[#GV]] = distinct !DIGlobalVariable(name: "true", scope: ![[#]], file: ![[#]], line: 3777, type: ![[#]], isLocal: true, isDefinition: true, declaration: ![[#DECLARATION:]])
+; CHECK-LLVM: ![[#DECLARATION]] = !DIDerivedType(tag: DW_TAG_member, name: "fully_specified", scope: ![[#SCOPE:]], file: ![[#]], line: 2, baseType: ![[#BASETYPE:]], flags: DIFlagPublic | DIFlagStaticMember)
+; CHECK-LLVM: ![[#SCOPE]] = {{.*}}!DICompositeType(tag: DW_TAG_structure_type, name: "A", file: ![[#]], line: 1, size: 8, flags: DIFlagTypePassByValue, elements: ![[#ELEMENTS:]], identifier: "_ZTS1A")
+; CHECK-LLVM: ![[#ELEMENTS]] = !{![[#DECLARATION]]}
+; CHECK-LLVM: ![[#BASETYPE]] = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+
+!llvm.module.flags = !{!0, !1}
+!llvm.dbg.cu = !{!2}
+
+!0 = !{i32 7, !"Dwarf Version", i32 4}
+!1 = !{i32 2, !"Debug Info Version", i32 3}
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang", emissionKind: FullDebug, globals: !4)
+!3 = !DIFile(filename: "test.cpp", directory: "/path/to")
+!4 = !{!5}
+!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+!6 = distinct !DIGlobalVariable(name: "true", scope: !2, file: !3, line: 3777, type: !7, isLocal: true, isDefinition: true, declaration: !10)
+!7 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8)
+!8 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)
+!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!10 = !DIDerivedType(tag: DW_TAG_member, name: "fully_specified", scope: !11, file: !3, line: 2, baseType: !9, flags: DIFlagStaticMember)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "A", file: !3, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !12, identifier: "_ZTS1A")
+!12 = !{!10}