akhuang created this revision.
akhuang added reviewers: rnk, dblaikie.
Herald added subscribers: cfe-commits, aprantl.
Herald added a project: clang.
This patch adds an option to limit debug info by only emitting complete class
type information when its constructor is emitted. This applies to classes
that have nontrivial user defined constructors.
I implemented the option by adding another level to `DebugInfoKind`, and
a flag `-flimit-debug-info-constructor`.
Total object file size on Windows, compiling with RelWithDebInfo:
before: 4,257,448 kb
after: 2,104,963 kb
And on Linux
before: 9,225,140 kb
after: 4,387,464 kb
According to the Windows clang.pdb files, here is a list of types that are no
longer complete with this option enabled: https://reviews.llvm.org/P8182
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D72427
Files:
clang/include/clang/Basic/CodeGenOptions.h
clang/include/clang/Basic/DebugInfoOptions.h
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/CGBlocks.cpp
clang/lib/CodeGen/CGDebugInfo.cpp
clang/lib/CodeGen/CGDecl.cpp
clang/lib/CodeGen/CGStmt.cpp
clang/lib/CodeGen/CGStmtOpenMP.cpp
clang/lib/CodeGen/CodeGenFunction.cpp
clang/lib/CodeGen/CodeGenModule.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Frontend/CompilerInvocation.cpp
clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
Index: clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/debug-info-limited-ctor.cpp
@@ -0,0 +1,72 @@
+// RUN: %clang -flimit-debug-info-constructor -emit-llvm -g -S %s -o - | FileCheck %s
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "A"
+// CHECK-NOT: DIFlagFwdDecl
+// CHECK-SAME: ){{$}}
+class A {
+public:
+ int z;
+};
+
+A *TestA(A* x) {
+ A *a = new A(*x);
+ return a;
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "B"
+// CHECK-SAME: flags: DIFlagFwdDecl
+class B {
+public:
+ int y;
+};
+
+extern int bar(B *b);
+int TestB(B *b) {
+ return bar(b);
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "C"
+// CHECK-SAME: flags: DIFlagFwdDecl
+class C {
+public:
+ C();
+};
+C *TestC() {
+ C *c = new C();
+ return c;
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "D"
+// CHECK-NOT: flags: DIFlagFwdDecl
+// CHECK-SAME: ){{$}}
+class D {
+public:
+ D() {}
+};
+D *TestD() {
+ D *d = new D();
+ return d;
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "E"
+// CHECK-NOT: flags: DIFlagFwdDecl
+// CHECK-SAME: ){{$}}
+class E {
+public:
+*d = new D();
+ return d;
+}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "E"
+// CHECK-NOT: flags: DIFlagFwdDecl
+// CHECK-SAME: ){{$}}
+class E {
+public:
+ E();
+};
+E::E() {}
+E *TestE() {
+ E *e = new E();
+ return e;
+}
+
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -731,6 +731,7 @@
llvm::StringSwitch<unsigned>(A->getValue())
.Case("line-tables-only", codegenoptions::DebugLineTablesOnly)
.Case("line-directives-only", codegenoptions::DebugDirectivesOnly)
+ .Case("constructor", codegenoptions::DebugInfoConstructor)
.Case("limited", codegenoptions::LimitedDebugInfo)
.Case("standalone", codegenoptions::FullDebugInfo)
.Default(~0U);
@@ -787,8 +788,7 @@
llvm::Triple::arm, llvm::Triple::armeb};
llvm::Triple T(TargetOpts.Triple);
- if (Opts.OptimizationLevel > 0 &&
- Opts.getDebugInfo() >= codegenoptions::LimitedDebugInfo &&
+ if (Opts.OptimizationLevel > 0 && Opts.isFullDebug() &&
llvm::is_contained(DebugEntryValueArchs, T.getArch()))
Opts.EnableDebugEntryValues = Args.hasArg(OPT_femit_debug_entry_values);
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -999,6 +999,9 @@
case codegenoptions::DebugLineTablesOnly:
CmdArgs.push_back("-debug-info-kind=line-tables-only");
break;
+ case codegenoptions::DebugInfoConstructor:
+ CmdArgs.push_back("-debug-info-kind=constructor");
+ break;
case codegenoptions::LimitedDebugInfo:
CmdArgs.push_back("-debug-info-kind=limited");
break;
@@ -3682,6 +3685,13 @@
if (DebugInfoKind == codegenoptions::LimitedDebugInfo && NeedFullDebug)
DebugInfoKind = codegenoptions::FullDebugInfo;
+ if (Args.hasFlag(options::OPT_flimit_debug_info_constructor,
+ options::OPT_fno_limit_debug_info_constructor, false))
+ if (checkDebugInfoOption(
+ Args.getLastArg(options::OPT_flimit_debug_info_constructor), Args, D, TC) &&
+ DebugInfoKind == codegenoptions::LimitedDebugInfo)
+ DebugInfoKind = codegenoptions::DebugInfoConstructor;
+
if (Args.hasFlag(options::OPT_gembed_source, options::OPT_gno_embed_source,
false)) {
// Source embedding is a vendor extension to DWARF v5. By now we have
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -4113,13 +4113,13 @@
// Emit global variable debug information.
if (CGDebugInfo *DI = getModuleDebugInfo())
- if (getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo)
+ if (getCodeGenOpts().isFullDebug())
DI->EmitGlobalVariable(GV, D);
}
void CodeGenModule::EmitExternalVarDeclaration(const VarDecl *D) {
if (CGDebugInfo *DI = getModuleDebugInfo())
- if (getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo) {
+ if (getCodeGenOpts().isFullDebug()) {
QualType ASTTy = D->getType();
llvm::Type *Ty = getTypes().ConvertTypeForMem(D->getType());
llvm::PointerType *PTy =
@@ -5366,7 +5366,7 @@
ObjCRuntime->GenerateClass(OMD);
// Emit global variable debug information.
if (CGDebugInfo *DI = getModuleDebugInfo())
- if (getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo)
+ if (getCodeGenOpts().isFullDebug())
DI->getOrCreateInterfaceType(getContext().getObjCInterfaceType(
OMD->getClassInterface()), OMD->getLocation());
break;
Index: clang/lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.cpp
+++ clang/lib/CodeGen/CodeGenFunction.cpp
@@ -2101,7 +2101,7 @@
const APValue &Init) {
assert(Init.hasValue() && "Invalid DeclRefExpr initializer!");
if (CGDebugInfo *Dbg = getDebugInfo())
- if (CGM.getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo)
+ if (CGM.getCodeGenOpts().isFullDebug())
Dbg->EmitGlobalVariable(E->getDecl(), Init);
}
Index: clang/lib/CodeGen/CGStmtOpenMP.cpp
===================================================================
--- clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -567,8 +567,7 @@
const CapturedDecl *CD = S.getCapturedDecl();
// Build the argument list.
bool NeedWrapperFunction =
- getDebugInfo() &&
- CGM.getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo;
+ getDebugInfo() && CGM.getCodeGenOpts().isFullDebug();
FunctionArgList Args;
llvm::MapVector<const Decl *, std::pair<const VarDecl *, Address>> LocalAddrs;
llvm::DenseMap<const Decl *, std::pair<const Expr *, llvm::Value *>> VLASizes;
Index: clang/lib/CodeGen/CGStmt.cpp
===================================================================
--- clang/lib/CodeGen/CGStmt.cpp
+++ clang/lib/CodeGen/CGStmt.cpp
@@ -562,8 +562,7 @@
// Emit debug info for labels.
if (CGDebugInfo *DI = getDebugInfo()) {
- if (CGM.getCodeGenOpts().getDebugInfo() >=
- codegenoptions::LimitedDebugInfo) {
+ if (CGM.getCodeGenOpts().isFullDebug()) {
DI->setLocation(D->getLocation());
DI->EmitLabel(D, Builder);
}
Index: clang/lib/CodeGen/CGDecl.cpp
===================================================================
--- clang/lib/CodeGen/CGDecl.cpp
+++ clang/lib/CodeGen/CGDecl.cpp
@@ -446,7 +446,7 @@
// Emit global variable debug descriptor for static vars.
CGDebugInfo *DI = getDebugInfo();
if (DI &&
- CGM.getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo) {
+ CGM.getCodeGenOpts().isFullDebug()) {
DI->setLocation(D.getLocation());
DI->EmitGlobalVariable(var, &D);
}
@@ -1393,8 +1393,7 @@
EmitVariablyModifiedType(Ty);
auto *DI = getDebugInfo();
- bool EmitDebugInfo = DI && CGM.getCodeGenOpts().getDebugInfo() >=
- codegenoptions::LimitedDebugInfo;
+ bool EmitDebugInfo = DI && CGM.getCodeGenOpts().isFullDebug();
Address address = Address::invalid();
Address AllocaAddr = Address::invalid();
@@ -2495,9 +2494,7 @@
// Emit debug info for param declarations in non-thunk functions.
if (CGDebugInfo *DI = getDebugInfo()) {
- if (CGM.getCodeGenOpts().getDebugInfo() >=
- codegenoptions::LimitedDebugInfo &&
- !CurFuncIsThunk) {
+ if (CGM.getCodeGenOpts().isFullDebug() && !CurFuncIsThunk) {
DI->EmitDeclareOfArgVariable(&D, DeclPtr.getPointer(), ArgNo, Builder);
}
}
Index: clang/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- clang/lib/CodeGen/CGDebugInfo.cpp
+++ clang/lib/CodeGen/CGDebugInfo.cpp
@@ -591,6 +591,7 @@
case codegenoptions::DebugDirectivesOnly:
EmissionKind = llvm::DICompileUnit::DebugDirectivesOnly;
break;
+ case codegenoptions::DebugInfoConstructor:
case codegenoptions::LimitedDebugInfo:
case codegenoptions::FullDebugInfo:
EmissionKind = llvm::DICompileUnit::FullDebug;
@@ -1647,6 +1648,12 @@
if (CGM.getLangOpts().Optimize)
SPFlags |= llvm::DISubprogram::SPFlagOptimized;
+ // In this debug mode, emit type info for a class when its constructor type
+ // info is emitted.
+ if (DebugKind == codegenoptions::DebugInfoConstructor)
+ if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(Method))
+ completeClass(CD->getParent());
+
llvm::DINodeArray TParamsArray = CollectFunctionTemplateParams(Method, Unit);
llvm::DISubprogram *SP = DBuilder.createMethod(
RecordTy, MethodName, MethodLinkageName, MethodDefUnit, MethodLine,
@@ -2043,7 +2050,7 @@
llvm::DIType *CGDebugInfo::getOrCreateRecordType(QualType RTy,
SourceLocation Loc) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
llvm::DIType *T = getOrCreateType(RTy, getOrCreateFile(Loc));
return T;
}
@@ -2055,7 +2062,7 @@
llvm::DIType *CGDebugInfo::getOrCreateStandaloneType(QualType D,
SourceLocation Loc) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
assert(!D.isNull() && "null type");
llvm::DIType *T = getOrCreateType(D, getOrCreateFile(Loc));
assert(T && "could not create debug info for type");
@@ -2210,6 +2217,17 @@
!isClassOrMethodDLLImport(CXXDecl))
return true;
+ // In constructor debug mode, only emit debug info for a class when its
+ // constructor is emitted. Skip this optimization if the class or any of
+ // its methods are marked dllimport.
+ if (DebugKind == codegenoptions::DebugInfoConstructor &&
+ !CXXDecl->isLambda() && !isClassOrMethodDLLImport(CXXDecl)) {
+ for (auto ctor : CXXDecl->ctors()) {
+ if (ctor->isUserProvided())
+ return true;
+ }
+ }
+
TemplateSpecializationKind Spec = TSK_Undeclared;
if (const auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD))
Spec = SD->getSpecializationKind();
@@ -3270,7 +3288,7 @@
DebugKind <= codegenoptions::DebugLineTablesOnly))
LinkageName = StringRef();
- if (DebugKind >= codegenoptions::LimitedDebugInfo) {
+ if (CGM.getCodeGenOpts().isFullDebug()) {
if (const NamespaceDecl *NSDecl =
dyn_cast_or_null<NamespaceDecl>(FD->getDeclContext()))
FDContext = getOrCreateNamespace(NSDecl);
@@ -3957,7 +3975,7 @@
llvm::Optional<unsigned> ArgNo,
CGBuilderTy &Builder,
const bool UsePointerValue) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
if (VD->hasAttr<NoDebugAttr>())
return nullptr;
@@ -4091,12 +4109,12 @@
CGDebugInfo::EmitDeclareOfAutoVariable(const VarDecl *VD, llvm::Value *Storage,
CGBuilderTy &Builder,
const bool UsePointerValue) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
return EmitDeclare(VD, Storage, llvm::None, Builder, UsePointerValue);
}
void CGDebugInfo::EmitLabel(const LabelDecl *D, CGBuilderTy &Builder) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
if (D->hasAttr<NoDebugAttr>())
@@ -4132,7 +4150,7 @@
void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
const VarDecl *VD, llvm::Value *Storage, CGBuilderTy &Builder,
const CGBlockInfo &blockInfo, llvm::Instruction *InsertPoint) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
if (Builder.GetInsertBlock() == nullptr)
@@ -4203,7 +4221,7 @@
void CGDebugInfo::EmitDeclareOfArgVariable(const VarDecl *VD, llvm::Value *AI,
unsigned ArgNo,
CGBuilderTy &Builder) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
EmitDeclare(VD, AI, ArgNo, Builder);
}
@@ -4260,7 +4278,7 @@
unsigned ArgNo,
llvm::AllocaInst *Alloca,
CGBuilderTy &Builder) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
ASTContext &C = CGM.getContext();
const BlockDecl *blockDecl = block.getBlockDecl();
@@ -4426,7 +4444,7 @@
void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
const VarDecl *D) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
if (D->hasAttr<NoDebugAttr>())
return;
@@ -4495,7 +4513,7 @@
}
void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
if (VD->hasAttr<NoDebugAttr>())
return;
llvm::TimeTraceScope TimeScope("DebugConstGlobalVariable", [&]() {
@@ -4594,7 +4612,7 @@
void CGDebugInfo::EmitExternalVariable(llvm::GlobalVariable *Var,
const VarDecl *D) {
- assert(DebugKind >= codegenoptions::LimitedDebugInfo);
+ assert(CGM.getCodeGenOpts().isFullDebug());
if (D->hasAttr<NoDebugAttr>())
return;
@@ -4619,7 +4637,7 @@
}
void CGDebugInfo::EmitUsingDirective(const UsingDirectiveDecl &UD) {
- if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
+ if (!CGM.getCodeGenOpts().isFullDebug())
return;
const NamespaceDecl *NSDecl = UD.getNominatedNamespace();
if (!NSDecl->isAnonymousNamespace() ||
@@ -4632,7 +4650,7 @@
}
void CGDebugInfo::EmitUsingDecl(const UsingDecl &UD) {
- if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
+ if (!CGM.getCodeGenOpts().isFullDebug())
return;
assert(UD.shadow_size() &&
"We shouldn't be codegening an invalid UsingDecl containing no decls");
@@ -4673,7 +4691,7 @@
llvm::DIImportedEntity *
CGDebugInfo::EmitNamespaceAlias(const NamespaceAliasDecl &NA) {
- if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
+ if (!CGM.getCodeGenOpts().isFullDebug())
return nullptr;
auto &VH = NamespaceAliasCache[&NA];
if (VH)
@@ -4795,7 +4813,7 @@
}
void CGDebugInfo::EmitExplicitCastType(QualType Ty) {
- if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
+ if (!CGM.getCodeGenOpts().isFullDebug())
return;
if (auto *DieTy = getOrCreateType(Ty, TheCU->getFile()))
Index: clang/lib/CodeGen/CGBlocks.cpp
===================================================================
--- clang/lib/CodeGen/CGBlocks.cpp
+++ clang/lib/CodeGen/CGBlocks.cpp
@@ -1483,8 +1483,7 @@
Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
Builder.CreateStore(arg, alloc);
if (CGDebugInfo *DI = getDebugInfo()) {
- if (CGM.getCodeGenOpts().getDebugInfo() >=
- codegenoptions::LimitedDebugInfo) {
+ if (CGM.getCodeGenOpts().isFullDebug()) {
DI->setLocation(D->getLocation());
DI->EmitDeclareOfBlockLiteralArgVariable(
*BlockInfo, D->getName(), argNum,
@@ -1656,8 +1655,7 @@
const VarDecl *variable = CI.getVariable();
DI->EmitLocation(Builder, variable->getLocation());
- if (CGM.getCodeGenOpts().getDebugInfo() >=
- codegenoptions::LimitedDebugInfo) {
+ if (CGM.getCodeGenOpts().isFullDebug()) {
const CGBlockInfo::Capture &capture = blockInfo.getCapture(variable);
if (capture.isConstant()) {
auto addr = LocalDeclMap.find(variable)->second;
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1781,6 +1781,11 @@
HelpText<"Limit debug information produced to reduce size of debug binary">;
def flimit_debug_info : Flag<["-"], "flimit-debug-info">, Flags<[CoreOption]>, Alias<fno_standalone_debug>;
def fno_limit_debug_info : Flag<["-"], "fno-limit-debug-info">, Flags<[CoreOption]>, Alias<fstandalone_debug>;
+def flimit_debug_info_constructor : Flag<["-"], "flimit-debug-info-constructor">, Group<f_Group>, Flags<[CoreOption]>,
+ HelpText<"Limit debug information by only emitting class debug info when its constructor "
+ "is emitted">;
+def fno_limit_debug_info_constructor : Flag<["-"], "fno-limit-debug-info-constructor">, Group<f_Group>, Flags<[CoreOption]>,
+ Alias<fno_standalone_debug>;
def fdebug_macro : Flag<["-"], "fdebug-macro">, Group<f_Group>, Flags<[CoreOption]>,
HelpText<"Emit macro debug information">;
def fno_debug_macro : Flag<["-"], "fno-debug-macro">, Group<f_Group>, Flags<[CoreOption]>,
Index: clang/include/clang/Basic/DebugInfoOptions.h
===================================================================
--- clang/include/clang/Basic/DebugInfoOptions.h
+++ clang/include/clang/Basic/DebugInfoOptions.h
@@ -34,6 +34,11 @@
/// (-gline-tables-only).
DebugLineTablesOnly,
+ /// Limit generated debug info for classes to reduce size. This emits class
+ /// type info only where the constructor is emitted, if it is a class that
+ /// has a constructor (-flimit-debug-info-constructor).
+ DebugInfoConstructor,
+
/// Limit generated debug info to reduce size (-fno-standalone-debug). This
/// emits forward decls for types that could be replaced with forward decls in
/// the source code. For dynamic C++ classes type info is only emitted into
Index: clang/include/clang/Basic/CodeGenOptions.h
===================================================================
--- clang/include/clang/Basic/CodeGenOptions.h
+++ clang/include/clang/Basic/CodeGenOptions.h
@@ -357,6 +357,11 @@
/// Check if CSIR profile use is on.
bool hasProfileCSIRUse() const { return getProfileUse() == ProfileCSIRInstr; }
+
+ /// Check if full debug info should be emitted.
+ bool isFullDebug() const {
+ return getDebugInfo() >= codegenoptions::DebugInfoConstructor;
+ }
};
} // end namespace clang
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