[clang] [clang] Add clang::debug_info_type attribute for bitfields (PR #69104)
Vlad Serebrennikov via cfe-commits
cfe-commits at lists.llvm.org
Sun Oct 15 03:55:27 PDT 2023
https://github.com/Endilll updated https://github.com/llvm/llvm-project/pull/69104
>From 976aa5c8f3d936a15e7123069a49d97ad3bf7a05 Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <serebrennikov.vladislav at gmail.com>
Date: Sun, 15 Oct 2023 13:14:55 +0300
Subject: [PATCH 1/3] [clang] Add clang::debug_info_type attribute
---
clang/include/clang/Basic/Attr.td | 11 ++++++++
clang/include/clang/Basic/AttrDocs.td | 12 +++++++++
.../clang/Basic/DiagnosticSemaKinds.td | 2 ++
clang/lib/CodeGen/CGDebugInfo.cpp | 2 ++
clang/lib/Sema/SemaDeclAttr.cpp | 26 +++++++++++++++++++
.../CodeGen/debug-info-debug-info-type.cpp | 14 ++++++++++
6 files changed, 67 insertions(+)
create mode 100644 clang/test/CodeGen/debug-info-debug-info-type.cpp
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 5c9eb7b8a981037..024421c0583c019 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -107,6 +107,10 @@ def NonBitField : SubsetSubject<Field,
[{!S->isBitField()}],
"non-bit-field non-static data members">;
+def BitField : SubsetSubject<Field,
+ [{S->isBitField()}],
+ "bit-field non-static data members">;
+
def NonStaticCXXMethod : SubsetSubject<CXXMethod,
[{!S->isStatic()}],
"non-static member functions">;
@@ -4264,3 +4268,10 @@ def CountedBy : InheritableAttr {
void setCountedByFieldLoc(SourceRange Loc) { CountedByFieldLoc = Loc; }
}];
}
+
+def DebugInfoType: InheritableAttr {
+ let Spellings = [Clang<"debug_info_type">];
+ let Subjects = SubjectList<[BitField], ErrorDiag>;
+ let Args = [TypeArgument<"Type", 1>];
+ let Documentation = [DebugInfoTypeDocumentation];
+}
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 9f9991bdae36155..6cceba1e0e0ad01 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -7219,6 +7219,18 @@ its underlying representation to be a WebAssembly ``funcref``.
}];
}
+def DebugInfoTypeDocumentation : Documentation {
+ let Category = DocCatField;
+ let Content = [{
+This attribute allows to alter type of a bitfield in debug information.
+Such a need might arise when bitfield is intended to store an enumeration value,
+but has to be specified as having enumeration's underlying type, in order to
+facilitate compiler optimizations. But this also causes underlying type to be
+emitted in debug information, making it hard for debuggers to map bitfield's
+value back to enumeration. This attribute helps with this.
+ }];
+}
+
def CleanupDocs : Documentation {
let Category = DocCatType;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index e85cd4d1a1ddc0d..b5c73494df367a6 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3153,6 +3153,8 @@ def err_invalid_branch_protection_spec : Error<
"invalid or misplaced branch protection specification '%0'">;
def warn_unsupported_branch_protection_spec : Warning<
"unsupported branch protection specification '%0'">, InGroup<BranchProtection>;
+def warn_attribute_underlying_type_mismatch : Warning<
+ "underlying type %0 of enumeration %1 doesn't match bitfield type %2">;
def warn_unsupported_target_attribute
: Warning<"%select{unsupported|duplicate|unknown}0%select{| CPU|"
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index c73a63e12f03aab..85aedd87b21d41e 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1497,6 +1497,8 @@ CGDebugInfo::createBitFieldType(const FieldDecl *BitFieldDecl,
llvm::DIScope *RecordTy, const RecordDecl *RD) {
StringRef Name = BitFieldDecl->getName();
QualType Ty = BitFieldDecl->getType();
+ if (BitFieldDecl->hasAttr<DebugInfoTypeAttr>())
+ Ty = BitFieldDecl->getAttr<DebugInfoTypeAttr>()->getType();
SourceLocation Loc = BitFieldDecl->getLocation();
llvm::DIFile *VUnit = getOrCreateFile(Loc);
llvm::DIType *DebugType = getOrCreateType(Ty, VUnit);
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index feb02cad9080e3e..8d58968b7f985c8 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5910,6 +5910,28 @@ static void handleBuiltinAliasAttr(Sema &S, Decl *D,
D->addAttr(::new (S.Context) BuiltinAliasAttr(S.Context, AL, Ident));
}
+static void handleDebugInfoTypeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+ if (!AL.hasParsedType()) {
+ S.Diag(AL.getLoc(), diag::err_attribute_wrong_number_arguments) << AL << 1;
+ return;
+ }
+
+ TypeSourceInfo *ParmTSI = nullptr;
+ QualType type = S.GetTypeFromParser(AL.getTypeArg(), &ParmTSI);
+ assert(ParmTSI && "no type source info for attribute argument");
+
+ if (type->isEnumeralType()) {
+ QualType BitfieldType = llvm::cast<FieldDecl>(D)->getType();
+ QualType EnumUnderlyingType = type->getAs<EnumType>()->getDecl()->getIntegerType();
+ if (EnumUnderlyingType != BitfieldType) {
+ S.Diag(AL.getLoc(), diag::warn_attribute_underlying_type_mismatch) << EnumUnderlyingType << type << BitfieldType;
+ return;
+ }
+ }
+
+ D->addAttr(::new (S.Context) DebugInfoTypeAttr(S.Context, AL, ParmTSI));
+}
+
//===----------------------------------------------------------------------===//
// Checker-specific attribute handlers.
//===----------------------------------------------------------------------===//
@@ -9629,6 +9651,10 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
handleBuiltinAliasAttr(S, D, AL);
break;
+ case ParsedAttr::AT_DebugInfoType:
+ handleDebugInfoTypeAttr(S, D, AL);
+ break;
+
case ParsedAttr::AT_UsingIfExists:
handleSimpleAttribute<UsingIfExistsAttr>(S, D, AL);
break;
diff --git a/clang/test/CodeGen/debug-info-debug-info-type.cpp b/clang/test/CodeGen/debug-info-debug-info-type.cpp
new file mode 100644
index 000000000000000..6104ce7463ef918
--- /dev/null
+++ b/clang/test/CodeGen/debug-info-debug-info-type.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang -target x86_64-linux -g -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -verify -DMISMATCH %s
+
+struct A {
+ enum E : unsigned {};
+ [[clang::debug_info_type(E)]] unsigned b : 2;
+#ifdef MISMATCH
+ [[clang::debug_info_type(E)]] int b2 : 2;
+ // expected-warning at -1 {{underlying type 'unsigned int' of enumeration 'E' doesn't match bitfield type 'int'}}
+#endif
+} a;
+
+// CHECK-DAG: [[ENUM:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "E"{{.*}}
+// CHECK-DAG: !DIDerivedType(tag: DW_TAG_member, name: "b",{{.*}} baseType: [[ENUM]]
\ No newline at end of file
>From 4330b70c2fde70010f1caabbf6562b61c701ef7e Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <serebrennikov.vladislav at gmail.com>
Date: Sun, 15 Oct 2023 13:34:09 +0300
Subject: [PATCH 2/3] Add newline to the test
---
clang/test/CodeGen/debug-info-debug-info-type.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/test/CodeGen/debug-info-debug-info-type.cpp b/clang/test/CodeGen/debug-info-debug-info-type.cpp
index 6104ce7463ef918..4b60d1b64be239f 100644
--- a/clang/test/CodeGen/debug-info-debug-info-type.cpp
+++ b/clang/test/CodeGen/debug-info-debug-info-type.cpp
@@ -11,4 +11,4 @@ struct A {
} a;
// CHECK-DAG: [[ENUM:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "E"{{.*}}
-// CHECK-DAG: !DIDerivedType(tag: DW_TAG_member, name: "b",{{.*}} baseType: [[ENUM]]
\ No newline at end of file
+// CHECK-DAG: !DIDerivedType(tag: DW_TAG_member, name: "b",{{.*}} baseType: [[ENUM]]
>From faf8238ae2a6362214e8176e4b9b7225fa7c8bd1 Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <serebrennikov.vladislav at gmail.com>
Date: Sun, 15 Oct 2023 13:55:13 +0300
Subject: [PATCH 3/3] Run clang-format
---
clang/lib/Sema/SemaDeclAttr.cpp | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 8d58968b7f985c8..294a73d2abf2d29 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5922,9 +5922,11 @@ static void handleDebugInfoTypeAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
if (type->isEnumeralType()) {
QualType BitfieldType = llvm::cast<FieldDecl>(D)->getType();
- QualType EnumUnderlyingType = type->getAs<EnumType>()->getDecl()->getIntegerType();
+ QualType EnumUnderlyingType =
+ type->getAs<EnumType>()->getDecl()->getIntegerType();
if (EnumUnderlyingType != BitfieldType) {
- S.Diag(AL.getLoc(), diag::warn_attribute_underlying_type_mismatch) << EnumUnderlyingType << type << BitfieldType;
+ S.Diag(AL.getLoc(), diag::warn_attribute_underlying_type_mismatch)
+ << EnumUnderlyingType << type << BitfieldType;
return;
}
}
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