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[Clang] implement -fno-eliminate-unused-debug-types 

Fixes pr/11710.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Resubmit after breaking Windows and OSX builds.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D80242
This commit is contained in:
Nick Desaulniers 2020-08-10 14:52:37 -07:00
parent 41d4120017
commit 4f2ad15db5
16 changed files with 182 additions and 22 deletions
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4
clang/docs/ClangCommandLineReference.rst
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@ -2154,6 +2154,10 @@ Emit section containing metadata on function stack sizes
Emit full debug info for all types used by the program
.. option:: -feliminate-unused-debug-types, -fno-eliminate-unused-debug-types
Suppress (or emit) debug info for types that are unused but defined by the program.
.. option:: -fstrict-aliasing, -fno-strict-aliasing
.. option:: -fstrict-enums, -fno-strict-enums

6
clang/docs/CommandGuide/clang.rst
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@ -433,6 +433,12 @@ Code Generation Options
never emit type information for types that are not referenced at all by the
program.
.. option:: -feliminate-unused-debug-types
By default, Clang does not emit type information for types that are defined
but not used in a program. To retain the debug info for these unused types,
the negation **-fno-eliminate-unused-debug-types** can be used.
.. option:: -fexceptions
Enable generation of unwind information. This allows exceptions to be thrown

6
clang/docs/UsersManual.rst
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@ -2352,6 +2352,12 @@ below. If multiple flags are present, the last one is used.
Generate complete debug info.
.. option:: -feliminate-unused-debug-types
By default, Clang does not emit type information for types that are defined
but not used in a program. To retain the debug info for these unused types,
the negation **-fno-eliminate-unused-debug-types** can be used.
Controlling Macro Debug Info Generation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

3
clang/include/clang/Basic/CodeGenOptions.def
View File

@ -288,7 +288,6 @@ CODEGENOPT(DebugFwdTemplateParams, 1, 0) ///< Whether to emit complete
///< template parameter descriptions in
///< forward declarations (versus just
///< including them in the name).
CODEGENOPT(EmitLLVMUseLists, 1, 0) ///< Control whether to serialize use-lists.
CODEGENOPT(WholeProgramVTables, 1, 0) ///< Whether to apply whole-program
@ -313,7 +312,7 @@ VALUE_CODEGENOPT(SmallDataLimit, 32, 0)
VALUE_CODEGENOPT(SSPBufferSize, 32, 0)
/// The kind of generated debug info.
ENUM_CODEGENOPT(DebugInfo, codegenoptions::DebugInfoKind, 3, codegenoptions::NoDebugInfo)
ENUM_CODEGENOPT(DebugInfo, codegenoptions::DebugInfoKind, 4, codegenoptions::NoDebugInfo)
/// Whether to generate macro debug info.
CODEGENOPT(MacroDebugInfo, 1, 0)

5
clang/include/clang/Basic/CodeGenOptions.h
View File

@ -388,6 +388,11 @@ public:
bool hasReducedDebugInfo() const {
return getDebugInfo() >= codegenoptions::DebugInfoConstructor;
}
/// Check if maybe unused type info should be emitted.
bool hasMaybeUnusedDebugInfo() const {
return getDebugInfo() >= codegenoptions::UnusedTypeInfo;
}
};
} // end namespace clang

6
clang/include/clang/Basic/DebugInfoOptions.h
View File

@ -46,7 +46,11 @@ enum DebugInfoKind {
LimitedDebugInfo,
/// Generate complete debug info.
FullDebugInfo
FullDebugInfo,
/// Generate debug info for types that may be unused in the source
/// (-fno-eliminate-unused-debug-types).
UnusedTypeInfo,
};
} // end namespace codegenoptions

3
clang/include/clang/Driver/Options.td
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@ -943,6 +943,8 @@ def fno_elide_type : Flag<["-"], "fno-elide-type">, Group<f_Group>,
Flags<[CC1Option]>,
HelpText<"Do not elide types when printing diagnostics">;
def feliminate_unused_debug_symbols : Flag<["-"], "feliminate-unused-debug-symbols">, Group<f_Group>;
defm eliminate_unused_debug_types : OptOutFFlag<"eliminate-unused-debug-types",
"Do not emit ", "Emit ", " debug info for defined but unused types">;
def femit_all_decls : Flag<["-"], "femit-all-decls">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Emit all declarations, even if unused">;
def femulated_tls : Flag<["-"], "femulated-tls">, Group<f_Group>, Flags<[CC1Option]>,
@ -3321,7 +3323,6 @@ def fdiagnostics_show_location_EQ : Joined<["-"], "fdiagnostics-show-location=">
defm fcheck_new : BooleanFFlag<"check-new">, Group<clang_ignored_f_Group>;
defm caller_saves : BooleanFFlag<"caller-saves">, Group<clang_ignored_gcc_optimization_f_Group>;
defm reorder_blocks : BooleanFFlag<"reorder-blocks">, Group<clang_ignored_gcc_optimization_f_Group>;
defm eliminate_unused_debug_types : BooleanFFlag<"eliminate-unused-debug-types">, Group<clang_ignored_f_Group>;
defm branch_count_reg : BooleanFFlag<"branch-count-reg">, Group<clang_ignored_gcc_optimization_f_Group>;
defm default_inline : BooleanFFlag<"default-inline">, Group<clang_ignored_gcc_optimization_f_Group>;
defm fat_lto_objects : BooleanFFlag<"fat-lto-objects">, Group<clang_ignored_gcc_optimization_f_Group>;

15
clang/lib/CodeGen/CGDebugInfo.cpp
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@ -606,6 +606,7 @@ void CGDebugInfo::CreateCompileUnit() {
case codegenoptions::DebugInfoConstructor:
case codegenoptions::LimitedDebugInfo:
case codegenoptions::FullDebugInfo:
case codegenoptions::UnusedTypeInfo:
EmissionKind = llvm::DICompileUnit::FullDebug;
break;
}
@ -4960,13 +4961,17 @@ void CGDebugInfo::finalize() {
DBuilder.finalize();
}
// Don't ignore in case of explicit cast where it is referenced indirectly.
void CGDebugInfo::EmitExplicitCastType(QualType Ty) {
if (!CGM.getCodeGenOpts().hasReducedDebugInfo())
return;
if (CGM.getCodeGenOpts().hasReducedDebugInfo())
if (auto *DieTy = getOrCreateType(Ty, TheCU->getFile()))
DBuilder.retainType(DieTy);
}
if (auto *DieTy = getOrCreateType(Ty, TheCU->getFile()))
// Don't ignore in case of explicit cast where it is referenced indirectly.
DBuilder.retainType(DieTy);
void CGDebugInfo::EmitAndRetainType(QualType Ty) {
if (CGM.getCodeGenOpts().hasMaybeUnusedDebugInfo())
if (auto *DieTy = getOrCreateType(Ty, TheCU->getFile()))
DBuilder.retainType(DieTy);
}
llvm::DebugLoc CGDebugInfo::SourceLocToDebugLoc(SourceLocation Loc) {

3
clang/lib/CodeGen/CGDebugInfo.h
View File

@ -490,6 +490,9 @@ public:
/// Emit the type explicitly casted to.
void EmitExplicitCastType(QualType Ty);
/// Emit the type even if it might not be used.
void EmitAndRetainType(QualType Ty);
/// Emit C++ using declaration.
void EmitUsingDecl(const UsingDecl &UD);

21
clang/lib/CodeGen/CGDecl.cpp
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@ -100,11 +100,19 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
case Decl::ObjCTypeParam:
case Decl::Binding:
llvm_unreachable("Declaration should not be in declstmts!");
case Decl::Function: // void X();
case Decl::Record: // struct/union/class X;
case Decl::Enum: // enum X;
case Decl::EnumConstant: // enum ? { X = ? }
case Decl::CXXRecord: // struct/union/class X; [C++]
if (CGDebugInfo *DI = getDebugInfo())
if (cast<RecordDecl>(D).getDefinition())
DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(&D)));
return;
case Decl::Enum: // enum X;
if (CGDebugInfo *DI = getDebugInfo())
if (cast<EnumDecl>(D).getDefinition())
DI->EmitAndRetainType(getContext().getEnumType(cast<EnumDecl>(&D)));
return;
case Decl::Function: // void X();
case Decl::EnumConstant: // enum ? { X = ? }
case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
case Decl::Label: // __label__ x;
case Decl::Import:
@ -157,12 +165,11 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
case Decl::Typedef: // typedef int X;
case Decl::TypeAlias: { // using X = int; [C++0x]
const TypedefNameDecl &TD = cast<TypedefNameDecl>(D);
QualType Ty = TD.getUnderlyingType();
QualType Ty = cast<TypedefNameDecl>(D).getUnderlyingType();
if (CGDebugInfo *DI = getDebugInfo())
DI->EmitAndRetainType(Ty);
if (Ty->isVariablyModifiedType())
EmitVariablyModifiedType(Ty);
return;
}
}

32
clang/lib/CodeGen/CodeGenModule.cpp
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@ -5392,16 +5392,21 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
Spec->hasDefinition())
DI->completeTemplateDefinition(*Spec);
} LLVM_FALLTHROUGH;
case Decl::CXXRecord:
if (CGDebugInfo *DI = getModuleDebugInfo())
case Decl::CXXRecord: {
CXXRecordDecl *CRD = cast<CXXRecordDecl>(D);
if (CGDebugInfo *DI = getModuleDebugInfo()) {
if (CRD->hasDefinition())
DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
if (auto *ES = D->getASTContext().getExternalSource())
if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
DI->completeUnusedClass(cast<CXXRecordDecl>(*D));
DI->completeUnusedClass(*CRD);
}
// Emit any static data members, they may be definitions.
for (auto *I : cast<CXXRecordDecl>(D)->decls())
for (auto *I : CRD->decls())
if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))
EmitTopLevelDecl(I);
break;
}
// No code generation needed.
case Decl::UsingShadow:
case Decl::ClassTemplate:
@ -5587,6 +5592,25 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
EmitOMPRequiresDecl(cast<OMPRequiresDecl>(D));
break;
case Decl::Typedef:
case Decl::TypeAlias: // using foo = bar; [C++11]
if (CGDebugInfo *DI = getModuleDebugInfo())
DI->EmitAndRetainType(
getContext().getTypedefType(cast<TypedefNameDecl>(D)));
break;
case Decl::Record:
if (CGDebugInfo *DI = getModuleDebugInfo())
if (cast<RecordDecl>(D)->getDefinition())
DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
break;
case Decl::Enum:
if (CGDebugInfo *DI = getModuleDebugInfo())
if (cast<EnumDecl>(D)->getDefinition())
DI->EmitAndRetainType(getContext().getEnumType(cast<EnumDecl>(D)));
break;
default:
// Make sure we handled everything we should, every other kind is a
// non-top-level decl. FIXME: Would be nice to have an isTopLevelDeclKind

13
clang/lib/Driver/ToolChains/Clang.cpp
View File

@ -976,6 +976,9 @@ static void RenderDebugEnablingArgs(const ArgList &Args, ArgStringList &CmdArgs,
case codegenoptions::FullDebugInfo:
CmdArgs.push_back("-debug-info-kind=standalone");
break;
case codegenoptions::UnusedTypeInfo:
CmdArgs.push_back("-debug-info-kind=unused-types");
break;
default:
break;
}
@ -3782,8 +3785,14 @@ static void RenderDebugOptions(const ToolChain &TC, const Driver &D,
TC.GetDefaultStandaloneDebug());
if (const Arg *A = Args.getLastArg(options::OPT_fstandalone_debug))
(void)checkDebugInfoOption(A, Args, D, TC);
if (DebugInfoKind == codegenoptions::LimitedDebugInfo && NeedFullDebug)
DebugInfoKind = codegenoptions::FullDebugInfo;
if (DebugInfoKind == codegenoptions::LimitedDebugInfo) {
if (Args.hasFlag(options::OPT_fno_eliminate_unused_debug_types,
options::OPT_feliminate_unused_debug_types, false))
DebugInfoKind = codegenoptions::UnusedTypeInfo;
else if (NeedFullDebug)
DebugInfoKind = codegenoptions::FullDebugInfo;
}
if (Args.hasFlag(options::OPT_gembed_source, options::OPT_gno_embed_source,
false)) {

1
clang/lib/Frontend/CompilerInvocation.cpp
View File

@ -767,6 +767,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
.Case("constructor", codegenoptions::DebugInfoConstructor)
.Case("limited", codegenoptions::LimitedDebugInfo)
.Case("standalone", codegenoptions::FullDebugInfo)
.Case("unused-types", codegenoptions::UnusedTypeInfo)
.Default(~0U);
if (Val == ~0U)
Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args)

47
clang/test/CodeGen/debug-info-unused-types.c Normal file
View File

@ -0,0 +1,47 @@
// RUN: %clang_cc1 -debug-info-kind=unused-types -emit-llvm -o - %s | FileCheck %s
// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - %s | FileCheck --check-prefix=NODBG %s
typedef int my_int;
struct foo {};
enum bar { BAR };
union baz {};
void quux(void) {
typedef int x;
struct y {};
enum z { Z };
union w {};
}
// Check that debug info is emitted for the typedef, struct, enum, and union
// when -fno-eliminate-unused-debug-types and -g are set.
// CHECK: !DICompileUnit{{.+}}retainedTypes: [[RETTYPES:![0-9]+]]
// CHECK: [[TYPE0:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "bar"
// CHECK: [[TYPE1:![0-9]+]] = !DIEnumerator(name: "BAR"
// CHECK: [[TYPE2:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z"
// CHECK: [[TYPE3:![0-9]+]] = !DIEnumerator(name: "Z"
// CHECK: [[RETTYPES]] = !{[[TYPE4:![0-9]+]], [[TYPE5:![0-9]+]], [[TYPE0]], [[TYPE6:![0-9]+]], {{![0-9]+}}, [[TYPE7:![0-9]+]], [[TYPE2]], [[TYPE8:![0-9]+]]}
// CHECK: [[TYPE4]] = !DIDerivedType(tag: DW_TAG_typedef, name: "my_int"
// CHECK: [[TYPE5]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
// CHECK: [[TYPE6]] = distinct !DICompositeType(tag: DW_TAG_union_type, name: "baz"
// CHECK: [[TYPE7]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "y"
// CHECK: [[TYPE8]] = distinct !DICompositeType(tag: DW_TAG_union_type, name: "w"
// Check that debug info is not emitted for the typedef, struct, enum, and
// union when -fno-eliminate-unused-debug-types and -g are not set. These are
// the same checks as above with `NODBG-NOT` rather than `CHECK`.
// NODBG-NOT: !DI{{CompositeType|Enumerator|DerivedType}}
// Check that debug info is not emitted for declarations. Obnoxious
// indentifiers are to avoid collisions with the SHA emittied as debug info.
struct unused_struct;
enum unused_enum;
union unused_union;
void b0(void) {
struct unused_local_struct;
enum unused_local_enum;
union unused_local_union;
}
// NODBG-NOT: name: "unused_

28
clang/test/CodeGen/debug-info-unused-types.cpp Normal file
View File

@ -0,0 +1,28 @@
// RUN: %clang_cc1 -debug-info-kind=unused-types -emit-llvm -o - %s | FileCheck %s
// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - %s | FileCheck --check-prefix=NODBG %s
using foo = int;
class bar {};
enum class baz { BAZ };
void quux() {
using x = int;
class y {};
enum class z { Z };
}
// CHECK: !DICompileUnit{{.+}}retainedTypes: [[RETTYPES:![0-9]+]]
// CHECK: [[TYPE0:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "baz"
// CHECK: [[TYPE1:![0-9]+]] = !DIEnumerator(name: "BAZ"
// CHECK: [[TYPE2:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z"
// CHECK: [[TYPE3:![0-9]+]] = !DIEnumerator(name: "Z"
// CHECK: [[RETTYPES]] = !{[[TYPE4:![0-9]+]], [[TYPE5:![0-9]+]], [[TYPE0]], {{![0-9]+}}, [[TYPE6:![0-9]+]], [[TYPE2]]}
// CHECK: [[TYPE4]] = !DIDerivedType(tag: DW_TAG_typedef, name: "foo"
// CHECK: [[TYPE5]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "bar"
// CHECK: [[TYPE6]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "y"
// NODBG-NOT: !DI{{CompositeType|Enumerator|DerivedType}}
class unused_class;
enum class unused_enum_class;
// NODBG-NOT: name: "unused_

11
clang/test/Driver/debug-options.c
View File

@ -361,3 +361,14 @@
// GEMBED_2: error: invalid argument '-gembed-source' only allowed with '-gdwarf-5'
// NOGEMBED_5-NOT: "-gembed-source"
// NOGEMBED_2-NOT: error: invalid argument '-gembed-source' only allowed with '-gdwarf-5'
//
// RUN: %clang -### -g -fno-eliminate-unused-debug-types -c %s 2>&1 \
// RUN: | FileCheck -check-prefix=DEBUG_UNUSED_TYPES %s
// DEBUG_UNUSED_TYPES: "-debug-info-kind=unused-types"
// DEBUG_UNUSED_TYPES-NOT: "-debug-info-kind=limited"
// RUN: %clang -### -g -feliminate-unused-debug-types -c %s 2>&1 \
// RUN: | FileCheck -check-prefix=NO_DEBUG_UNUSED_TYPES %s
// RUN: %clang -### -fno-eliminate-unused-debug-types -g1 -c %s 2>&1 \
// RUN: | FileCheck -check-prefix=NO_DEBUG_UNUSED_TYPES %s
// NO_DEBUG_UNUSED_TYPES: "-debug-info-kind={{limited|line-tables-only|standalone}}"
// NO_DEBUG_UNUSED_TYPES-NOT: "-debug-info-kind=unused-types"