https://github.com/huangjd created
https://github.com/llvm/llvm-project/pull/95174
The option is causing the binary output to be different when compiled under
`-O0`, because it introduce dbg.declare on pseudovariables. Going to change
this implementation to use dbg.value instead.
>From c72d4de2a1dc4e641d61b3f31185181855a1d434 Mon Sep 17 00:00:00 2001
From: William Huang <williamjhu...@google.com>
Date: Tue, 11 Jun 2024 17:19:07 -0400
Subject: [PATCH 1/2] Revert "[Clang] Extend EmitPseudoVariable to support
debug records (#94956)"
This reverts commit 5c268cfaae521dc2db1af58085e3c8d66a5533fe.
---
clang/lib/CodeGen/CGDebugInfo.cpp | 32 +++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp
b/clang/lib/CodeGen/CGDebugInfo.cpp
index 11e2d549d8a45..681a475f9e4be 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -5766,16 +5766,28 @@ void CGDebugInfo::EmitPseudoVariable(CGBuilderTy
&Builder,
// it is loaded upon use, so we identify such pattern here.
if (llvm::LoadInst *Load = dyn_cast<llvm::LoadInst>(Value)) {
llvm::Value *Var = Load->getPointerOperand();
- // There can be implicit type cast applied on a variable if it is an opaque
- // ptr, in this case its debug info may not match the actual type of object
- // being used as in the next instruction, so we will need to emit a pseudo
- // variable for type-casted value.
- auto DeclareTypeMatches = [&](auto *DbgDeclare) {
- return DbgDeclare->getVariable()->getType() == Type;
- };
- if (any_of(llvm::findDbgDeclares(Var), DeclareTypeMatches) ||
- any_of(llvm::findDVRDeclares(Var), DeclareTypeMatches))
- return;
+ if (llvm::Metadata *MDValue = llvm::ValueAsMetadata::getIfExists(Var)) {
+ if (llvm::Value *DbgValue = llvm::MetadataAsValue::getIfExists(
+ CGM.getLLVMContext(), MDValue)) {
+ for (llvm::User *U : DbgValue->users()) {
+ if (llvm::CallInst *DbgDeclare = dyn_cast<llvm::CallInst>(U)) {
+ if (DbgDeclare->getCalledFunction()->getIntrinsicID() ==
+ llvm::Intrinsic::dbg_declare &&
+ DbgDeclare->getArgOperand(0) == DbgValue) {
+ // There can be implicit type cast applied on a variable if it is
+ // an opaque ptr, in this case its debug info may not match the
+ // actual type of object being used as in the next instruction,
so
+ // we will need to emit a pseudo variable for type-casted value.
+ llvm::DILocalVariable *MDNode = cast<llvm::DILocalVariable>(
+ cast<llvm::MetadataAsValue>(DbgDeclare->getOperand(1))
+ ->getMetadata());
+ if (MDNode->getType() == Type)
+ return;
+ }
+ }
+ }
+ }
+ }
}
// Find the correct location to insert a sequence of instructions to
>From 83a179ba9db812492f37ccbe00f58f534a993fe1 Mon Sep 17 00:00:00 2001
From: William Huang <williamjhu...@google.com>
Date: Tue, 11 Jun 2024 17:19:22 -0400
Subject: [PATCH 2/2] Revert "Add option to generate additional debug info for
expression dereferencing pointer to pointers. (#94100)"
This reverts commit 5cb00785aa56d4acc97b083df5305d2959f6bd4a.
---
clang/lib/CodeGen/CGDebugInfo.cpp | 84 ------------
clang/lib/CodeGen/CGDebugInfo.h | 6 -
clang/lib/CodeGen/CGExprScalar.cpp | 21 +--
.../test/CodeGenCXX/debug-info-ptr-to-ptr.cpp | 120 ------------------
4 files changed, 1 insertion(+), 230 deletions(-)
delete mode 100644 clang/test/CodeGenCXX/debug-info-ptr-to-ptr.cpp
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp
b/clang/lib/CodeGen/CGDebugInfo.cpp
index 681a475f9e4be..99e12da0081af 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -5746,90 +5746,6 @@ void
CGDebugInfo::EmitExternalVariable(llvm::GlobalVariable *Var,
Var->addDebugInfo(GVE);
}
-void CGDebugInfo::EmitPseudoVariable(CGBuilderTy &Builder,
- llvm::Instruction *Value, QualType Ty) {
- // Only when -g2 or above is specified, debug info for variables will be
- // generated.
- if (CGM.getCodeGenOpts().getDebugInfo() <=
- llvm::codegenoptions::DebugLineTablesOnly)
- return;
-
- llvm::DebugLoc SaveDebugLoc = Builder.getCurrentDebugLocation();
- if (!SaveDebugLoc.get())
- return;
-
- llvm::DIFile *Unit = SaveDebugLoc->getFile();
- llvm::DIType *Type = getOrCreateType(Ty, Unit);
-
- // Check if Value is already a declared variable and has debug info, in this
- // case we have nothing to do. Clang emits declared variable as alloca, and
- // it is loaded upon use, so we identify such pattern here.
- if (llvm::LoadInst *Load = dyn_cast<llvm::LoadInst>(Value)) {
- llvm::Value *Var = Load->getPointerOperand();
- if (llvm::Metadata *MDValue = llvm::ValueAsMetadata::getIfExists(Var)) {
- if (llvm::Value *DbgValue = llvm::MetadataAsValue::getIfExists(
- CGM.getLLVMContext(), MDValue)) {
- for (llvm::User *U : DbgValue->users()) {
- if (llvm::CallInst *DbgDeclare = dyn_cast<llvm::CallInst>(U)) {
- if (DbgDeclare->getCalledFunction()->getIntrinsicID() ==
- llvm::Intrinsic::dbg_declare &&
- DbgDeclare->getArgOperand(0) == DbgValue) {
- // There can be implicit type cast applied on a variable if it is
- // an opaque ptr, in this case its debug info may not match the
- // actual type of object being used as in the next instruction,
so
- // we will need to emit a pseudo variable for type-casted value.
- llvm::DILocalVariable *MDNode = cast<llvm::DILocalVariable>(
- cast<llvm::MetadataAsValue>(DbgDeclare->getOperand(1))
- ->getMetadata());
- if (MDNode->getType() == Type)
- return;
- }
- }
- }
- }
- }
- }
-
- // Find the correct location to insert a sequence of instructions to
- // materialize Value on the stack.
- auto SaveInsertionPoint = Builder.saveIP();
- if (llvm::InvokeInst *Invoke = dyn_cast<llvm::InvokeInst>(Value))
- Builder.SetInsertPoint(Invoke->getNormalDest()->begin());
- else if (llvm::Instruction *Next = Value->getIterator()->getNextNode())
- Builder.SetInsertPoint(Next);
- else
- Builder.SetInsertPoint(Value->getParent());
- llvm::DebugLoc DL = Value->getDebugLoc();
- if (DL.get())
- Builder.SetCurrentDebugLocation(DL);
- else if (!Builder.getCurrentDebugLocation().get())
- Builder.SetCurrentDebugLocation(SaveDebugLoc);
-
- llvm::AllocaInst *PseudoVar = Builder.CreateAlloca(Value->getType());
- Address PseudoVarAddr(PseudoVar, Value->getType(),
- CharUnits::fromQuantity(PseudoVar->getAlign()));
- llvm::LoadInst *Load = Builder.CreateLoad(PseudoVarAddr);
- Value->replaceAllUsesWith(Load);
- Builder.SetInsertPoint(Load);
- Builder.CreateStore(Value, PseudoVarAddr);
-
- // Emit debug info for materialized Value.
- unsigned Line = Builder.getCurrentDebugLocation().getLine();
- unsigned Column = Builder.getCurrentDebugLocation().getCol();
- llvm::DILocalVariable *D = DBuilder.createAutoVariable(
- LexicalBlockStack.back(), "", nullptr, 0, Type, false,
- llvm::DINode::FlagArtificial);
- llvm::DILocation *DIL =
- llvm::DILocation::get(CGM.getLLVMContext(), Line, Column,
- LexicalBlockStack.back(), CurInlinedAt);
- SmallVector<uint64_t> Expr;
- DBuilder.insertDeclare(PseudoVar, D, DBuilder.createExpression(Expr), DIL,
- Load);
-
- Builder.restoreIP(SaveInsertionPoint);
- Builder.SetCurrentDebugLocation(SaveDebugLoc);
-}
-
void CGDebugInfo::EmitGlobalAlias(const llvm::GlobalValue *GV,
const GlobalDecl GD) {
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index da466837aa3c3..8fe738be21568 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -530,12 +530,6 @@ class CGDebugInfo {
/// Emit information about an external variable.
void EmitExternalVariable(llvm::GlobalVariable *GV, const VarDecl *Decl);
- /// Emit a pseudo variable and debug info for an intermediate value if it
does
- /// not correspond to a variable in the source code, so that a profiler can
- /// track more accurate usage of certain instructions of interest.
- void EmitPseudoVariable(CGBuilderTy &Builder, llvm::Instruction *Value,
- QualType Ty);
-
/// Emit information about global variable alias.
void EmitGlobalAlias(const llvm::GlobalValue *GV, const GlobalDecl Decl);
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp
b/clang/lib/CodeGen/CGExprScalar.cpp
index 58f0a3113b4f8..1b144c178ce96 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1937,26 +1937,7 @@ Value *ScalarExprEmitter::VisitMemberExpr(MemberExpr *E)
{
}
}
- llvm::Value *Result = EmitLoadOfLValue(E);
-
- // If -fdebug-info-for-profiling is specified, emit a pseudo variable and its
- // debug info for the pointer, even if there is no variable associated with
- // the pointer's expression.
- if (CGF.CGM.getCodeGenOpts().DebugInfoForProfiling && CGF.getDebugInfo()) {
- if (llvm::LoadInst *Load = dyn_cast<llvm::LoadInst>(Result)) {
- if (llvm::GetElementPtrInst *GEP =
- dyn_cast<llvm::GetElementPtrInst>(Load->getPointerOperand())) {
- if (llvm::Instruction *Pointer =
- dyn_cast<llvm::Instruction>(GEP->getPointerOperand())) {
- QualType Ty = E->getBase()->getType();
- if (!E->isArrow())
- Ty = CGF.getContext().getPointerType(Ty);
- CGF.getDebugInfo()->EmitPseudoVariable(Builder, Pointer, Ty);
- }
- }
- }
- }
- return Result;
+ return EmitLoadOfLValue(E);
}
Value *ScalarExprEmitter::VisitArraySubscriptExpr(ArraySubscriptExpr *E) {
diff --git a/clang/test/CodeGenCXX/debug-info-ptr-to-ptr.cpp
b/clang/test/CodeGenCXX/debug-info-ptr-to-ptr.cpp
deleted file mode 100644
index baf791487771c..0000000000000
--- a/clang/test/CodeGenCXX/debug-info-ptr-to-ptr.cpp
+++ /dev/null
@@ -1,120 +0,0 @@
-// Test debug info for intermediate value of a chained pointer deferencing
-// expression when the flag -fdebug-info-for-pointer-type is enabled.
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-linux-gnu %s
-fdebug-info-for-profiling -debug-info-kind=constructor -o - | FileCheck %s
-
-class A {
-public:
- int i;
- char c;
- void *p;
- int arr[3];
-};
-
-class B {
-public:
- A* a;
-};
-
-class C {
-public:
- B* b;
- A* a;
- A arr[10];
-};
-
-// CHECK-LABEL: define dso_local noundef i32 @{{.*}}func1{{.*}}(
-// CHECK: [[A_ADDR:%.*]] = getelementptr inbounds %class.B, ptr
{{%.*}}, i32 0, i32 0, !dbg [[DBG1:![0-9]+]]
-// CHECK-NEXT: [[A:%.*]] = load ptr, ptr [[A_ADDR]], align {{.*}}, !dbg
[[DBG1]]
-// CHECK-NEXT: [[PSEUDO1:%.*]] = alloca ptr, align {{.*}}, !dbg [[DBG1]]
-// CHECK-NEXT: store ptr [[A]], ptr [[PSEUDO1]], align {{.*}}, !dbg [[DBG1]]
-// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[PSEUDO1]],
metadata [[META1:![0-9]+]], metadata !DIExpression()), !dbg [[DBG1]]
-// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[PSEUDO1]], align {{.*}}, !dbg
[[DBG1]]
-// CHECK-NEXT: {{%.*}} = getelementptr inbounds %class.A, ptr [[TMP1]], i32
0, i32 0,
-int func1(B *b) {
- return b->a->i;
-}
-
-// Should generate a pseudo variable when pointer is type-casted.
-// CHECK-LABEL: define dso_local noundef ptr @{{.*}}func2{{.*}}(
-// CHECK: call void @llvm.dbg.declare(metadata ptr [[B_ADDR:%.*]],
metadata [[META2:![0-9]+]], metadata !DIExpression())
-// CHECK-NEXT: [[B:%.*]] = load ptr, ptr [[B_ADDR]],
-// CHECK-NEXT: [[PSEUDO1:%.*]] = alloca ptr,
-// CHECK-NEXT: store ptr [[B]], ptr [[PSEUDO1]],
-// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[PSEUDO1]],
metadata [[META3:![0-9]+]], metadata !DIExpression())
-// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[PSEUDO1]],
-// CHECK-NEXT: {{%.*}} = getelementptr inbounds %class.B, ptr [[TMP1]], i32
0,
-A* func2(void *b) {
- return ((B*)b)->a;
-}
-
-// Should not generate pseudo variable in this case.
-// CHECK-LABEL: define dso_local noundef i32 @{{.*}}func3{{.*}}(
-// CHECK: call void @llvm.dbg.declare(metadata ptr [[B_ADDR:%.*]], metadata
[[META4:![0-9]+]], metadata !DIExpression())
-// CHECK: call void @llvm.dbg.declare(metadata ptr [[LOCAL1:%.*]], metadata
[[META5:![0-9]+]], metadata !DIExpression())
-// CHECK-NOT: call void @llvm.dbg.declare(metadata ptr
-int func3(B *b) {
- A *local1 = b->a;
- return local1->i;
-}
-
-// CHECK-LABEL: define dso_local noundef signext i8 @{{.*}}func4{{.*}}(
-// CHECK: [[A_ADDR:%.*]] = getelementptr inbounds %class.C, ptr
{{%.*}}, i32 0, i32 1
-// CHECK-NEXT: [[A:%.*]] = load ptr, ptr [[A_ADDR]],
-// CHECK-NEXT: [[PSEUDO1:%.*]] = alloca ptr,
-// CHECK-NEXT: store ptr [[A]], ptr [[PSEUDO1]],
-// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[PSEUDO1]],
metadata [[META6:![0-9]+]], metadata !DIExpression())
-// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[PSEUDO1]],
-// CHECK-NEXT: {{%.*}} = getelementptr inbounds %class.A, ptr [[TMP1]], i32
0, i32 0,
-// CHECK: [[CALL:%.*]] = call noundef ptr @{{.*}}foo{{.*}}(
-// CHECK-NEXT: [[PSEUDO2:%.*]] = alloca ptr,
-// CHECK-NEXT: store ptr [[CALL]], ptr [[PSEUDO2]]
-// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[PSEUDO2]],
metadata [[META6]], metadata !DIExpression())
-// CHECK-NEXT: [[TMP2:%.*]] = load ptr, ptr [[PSEUDO2]]
-// CHECK-NEXT: [[I1:%.*]] = getelementptr inbounds %class.A, ptr [[TMP2]],
i32 0, i32 1
-char func4(C *c) {
- extern A* foo(int x);
- return foo(c->a->i)->c;
-}
-
-// CHECK-LABEL: define dso_local noundef signext i8 @{{.*}}func5{{.*}}(
-// CHECK: call void @llvm.dbg.declare(metadata ptr {{%.*}}, metadata
[[META7:![0-9]+]], metadata !DIExpression())
-// CHECK: call void @llvm.dbg.declare(metadata ptr {{%.*}}, metadata
[[META8:![0-9]+]], metadata !DIExpression())
-// CHECK: [[A_ADDR:%.*]] = getelementptr inbounds %class.A, ptr
{{%.*}}, i64 {{%.*}},
-// CHECK-NEXT: [[PSEUDO1:%.*]] = alloca ptr,
-// CHECK-NEXT: store ptr [[A_ADDR]], ptr [[PSEUDO1]],
-// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[PSEUDO1]],
metadata [[META9:![0-9]+]], metadata !DIExpression())
-// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[PSEUDO1]],
-// CHECK-NEXT: {{%.*}} = getelementptr inbounds %class.A, ptr [[TMP1]], i32
0, i32 1,
-char func5(void *arr, int n) {
- return ((A*)arr)[n].c;
-}
-
-// CHECK-LABEL: define dso_local noundef i32 @{{.*}}func6{{.*}}(
-// CHECK: call void @llvm.dbg.declare(metadata ptr {{%.*}}, metadata
[[META10:![0-9]+]], metadata !DIExpression())
-// CHECK: call void @llvm.dbg.declare(metadata ptr {{%.*}}, metadata
[[META11:![0-9]+]], metadata !DIExpression())
-int func6(B &b) {
- return reinterpret_cast<A&>(b).i;
-}
-
-// CHECK-DAG: [[META_A:![0-9]+]] = distinct !DICompositeType(tag:
DW_TAG_class_type, name: "A",
-// CHECK-DAG: [[META_AP:![0-9]+]] = !DIDerivedType(tag: DW_TAG_pointer_type,
baseType: [[META_A]],
-// CHECK-DAG: [[META_B:![0-9]+]] = distinct !DICompositeType(tag:
DW_TAG_class_type, name: "B",
-// CHECK-DAG: [[META_BP:![0-9]+]] = !DIDerivedType(tag: DW_TAG_pointer_type,
baseType: [[META_B]],
-// CHECK-DAG: [[META_C:![0-9]+]] = distinct !DICompositeType(tag:
DW_TAG_class_type, name: "C",
-// CHECK-DAG: [[META_CP:![0-9]+]] = !DIDerivedType(tag: DW_TAG_pointer_type,
baseType: [[META_C]],
-// CHECK-DAG: [[META_VP:![0-9]+]] = !DIDerivedType(tag: DW_TAG_pointer_type,
baseType: null,
-// CHECK-DAG: [[META_I32:![0-9]+]] = !DIBasicType(name: "int", size: 32,
-// CHECK-DAG: [[META_BR:![0-9]+]] = !DIDerivedType(tag: DW_TAG_reference_type,
baseType: [[META_B]],
-
-// CHECK-DAG: [[DBG1]] = !DILocation(line: 34, column: 13,
-// CHECK-DAG: [[META1]] = !DILocalVariable(scope: {{.*}}, type: [[META_AP]],
flags: DIFlagArtificial)
-// CHECK-DAG: [[META2]] = !DILocalVariable(name: "b", arg: 1, scope: {{.*}},
file: {{.*}}, line: 46, type: [[META_VP]])
-// CHECK-DAG: [[META3]] = !DILocalVariable(scope: {{.*}}, type: [[META_BP]],
flags: DIFlagArtificial)
-// CHECK-DAG: [[META4]] = !DILocalVariable(name: "b", arg: 1, scope: {{.*}},
file: {{.*}}, line: 55, type: [[META_BP]])
-// CHECK-DAG: [[META5]] = !DILocalVariable(name: "local1", scope: {{.*}},
file: {{.*}}, line: 56, type: [[META_AP]])
-// CHECK-DAG: [[META6]] = !DILocalVariable(scope: {{.*}}, type: [[META_AP]],
flags: DIFlagArtificial)
-// CHECK-DAG: [[META7]] = !DILocalVariable(name: "arr", arg: 1, scope: {{.*}},
file: {{.*}}, line: 88, type: [[META_VP]])
-// CHECK-DAG: [[META8]] = !DILocalVariable(name: "n", arg: 2, scope: {{.*}},
file: {{.*}}, line: 88, type: [[META_I32]])
-// CHECK-DAG: [[META9]] = !DILocalVariable(scope: {{.*}}, type: [[META_AP]],
flags: DIFlagArtificial)
-// CHECK-DAG: [[META10]] = !DILocalVariable(name: "b", arg: 1, scope: {{.*}},
file: {{.*}}, line: 95, type: [[META_BR]])
-// CHECK-DAG: [[META11]] = !DILocalVariable(scope: {{.*}}, type: [[META_AP]],
flags: DIFlagArtificial)
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