[clang] [llvm] [DebugInfo] Emit DW_AT_bit_size for _BitInt types and others (PR #164372)
Orlando Cazalet-Hyams via cfe-commits
cfe-commits at lists.llvm.org
Wed Oct 29 04:12:45 PDT 2025
https://github.com/OCHyams updated https://github.com/llvm/llvm-project/pull/164372
>From 83f7c7c070f1b3912b09974944c9e6783efe1983 Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Mon, 20 Oct 2025 17:00:06 +0100
Subject: [PATCH 1/6] [DebugInfo] Emit DW_AT_bit_size for _BitSize types and
others
DW_TAG_base_type DIEs are permitted to have both byte_size and bit_size
attributes "If the value of an object of the given type does not fully occupy
the storage described by a byte size attribute"
Change Clang to emit the actual bit-size of _BitInt in debug metadata, and
change LLVM to add DW_AT_bit_size to base_type DIEs when the condition above is
true.
---
clang/lib/CodeGen/CGDebugInfo.cpp | 4 +-
clang/test/DebugInfo/Generic/bit-int.c | 8 ++++
.../CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 5 +++
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 13 ++++++-
llvm/test/DebugInfo/bit-int-size.ll | 38 +++++++++++++++++++
5 files changed, 63 insertions(+), 5 deletions(-)
create mode 100644 clang/test/DebugInfo/Generic/bit-int.c
create mode 100644 llvm/test/DebugInfo/bit-int-size.ll
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 12e2813ef2ec7..2ad187de16acc 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1152,9 +1152,7 @@ llvm::DIType *CGDebugInfo::CreateType(const BitIntType *Ty) {
llvm::dwarf::TypeKind Encoding = Ty->isUnsigned()
? llvm::dwarf::DW_ATE_unsigned
: llvm::dwarf::DW_ATE_signed;
-
- return DBuilder.createBasicType(Name, CGM.getContext().getTypeSize(Ty),
- Encoding);
+ return DBuilder.createBasicType(Name, Ty->getNumBits(), Encoding);
}
llvm::DIType *CGDebugInfo::CreateType(const ComplexType *Ty) {
diff --git a/clang/test/DebugInfo/Generic/bit-int.c b/clang/test/DebugInfo/Generic/bit-int.c
new file mode 100644
index 0000000000000..16b3d7a2582c9
--- /dev/null
+++ b/clang/test/DebugInfo/Generic/bit-int.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -x c++ %s -debug-info-kind=standalone -gno-column-info -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -x c %s -debug-info-kind=standalone -gno-column-info -emit-llvm -o - | FileCheck %s
+
+unsigned _BitInt(2) a;
+_BitInt(2) b;
+
+// CHECK: !DIBasicType(name: "_BitInt", size: 2, encoding: DW_ATE_signed)
+// CHECK: !DIBasicType(name: "unsigned _BitInt", size: 2, encoding: DW_ATE_unsigned)
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 518121e200190..6f68548aa25f4 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1795,6 +1795,11 @@ void DwarfCompileUnit::createBaseTypeDIEs() {
// Round up to smallest number of bytes that contains this number of bits.
addUInt(Die, dwarf::DW_AT_byte_size, std::nullopt,
divideCeil(Btr.BitSize, 8));
+ // If the value of an object of the given type does not fully occupy the
+ // storage described by a byte size attribute, the base type entry may also
+ // have a DW_AT_bit_size [...] attribute.
+ if (Btr.BitSize && (Btr.BitSize % 8))
+ addUInt(Die, dwarf::DW_AT_bit_size, std::nullopt, Btr.BitSize);
Btr.Die = &Die;
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index e40fb768027b8..1253d9a463cbb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -766,8 +766,17 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIBasicType *BTy) {
addUInt(Buffer, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
BTy->getEncoding());
- uint64_t Size = BTy->getSizeInBits() >> 3;
- addUInt(Buffer, dwarf::DW_AT_byte_size, std::nullopt, Size);
+ uint64_t SizeInBytes = divideCeil(BTy->getSizeInBits(), 8);
+ addUInt(Buffer, dwarf::DW_AT_byte_size, std::nullopt, SizeInBytes);
+ if (BTy->getTag() == dwarf::Tag::DW_TAG_base_type) {
+ // DW_TAG_base_type:
+ // If the value of an object of the given type does not fully occupy the
+ // storage described by a byte size attribute, the base type entry may also
+ // have a DW_AT_bit_size [...] attribute.
+ if (uint64_t SizeInBits = BTy->getSizeInBits();
+ SizeInBits && SizeInBits % 8)
+ addUInt(Buffer, dwarf::DW_AT_bit_size, std::nullopt, SizeInBits);
+ }
if (BTy->isBigEndian())
addUInt(Buffer, dwarf::DW_AT_endianity, std::nullopt, dwarf::DW_END_big);
diff --git a/llvm/test/DebugInfo/bit-int-size.ll b/llvm/test/DebugInfo/bit-int-size.ll
new file mode 100644
index 0000000000000..69ab756f4e288
--- /dev/null
+++ b/llvm/test/DebugInfo/bit-int-size.ll
@@ -0,0 +1,38 @@
+; RUN: %llc_dwarf %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck %s
+; REQUIRES: object-emission
+
+;; Check base types with bit-sizes that don't fit fully fit within a byte
+;; multiple get both a a byte_size and bit_size attribute.
+
+; CHECK: DW_TAG_base_type
+; CHECK-NEXT: DW_AT_name ("unsigned _BitInt")
+; CHECK-NEXT: DW_AT_encoding (DW_ATE_unsigned)
+; CHECK-NEXT: DW_AT_byte_size (0x02)
+; CHECK-NEXT: DW_AT_bit_size (0x09)
+
+; CHECK: DW_TAG_base_type
+; CHECK-NEXT: DW_AT_name ("unsigned _BitInt")
+; CHECK-NEXT: DW_AT_encoding (DW_ATE_signed)
+; CHECK-NEXT: DW_AT_byte_size (0x01)
+; CHECK-NEXT: DW_AT_bit_size (0x02)
+
+ at a = global i8 0, align 1, !dbg !0
+ at b = global i8 0, align 1, !dbg !5
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!10, !11}
+!llvm.ident = !{!12}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !7, line: 4, type: !9, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 22.0.0git", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "bit-int.c", directory: "/")
+!4 = !{!0, !5}
+!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
+!6 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !7, line: 5, type: !8, isLocal: false, isDefinition: true)
+!7 = !DIFile(filename: "bit-int.c", directory: "/")
+!8 = !DIBasicType(name: "_BitInt", size: 2, encoding: DW_ATE_signed)
+!9 = !DIBasicType(name: "unsigned _BitInt", size: 2, encoding: DW_ATE_unsigned)
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!11 = !{i32 1, !"wchar_size", i32 4}
+!12 = !{!"clang version 22.0.0git"}
>From 87d56305a8d237dae848b4594514aedd6d1f4aad Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Tue, 21 Oct 2025 13:33:12 +0100
Subject: [PATCH 2/6] add check to base-type-size.ll
---
llvm/test/DebugInfo/X86/base-type-size.ll | 1 +
1 file changed, 1 insertion(+)
diff --git a/llvm/test/DebugInfo/X86/base-type-size.ll b/llvm/test/DebugInfo/X86/base-type-size.ll
index 3a8dc37bdc65f..cb0c1eb63e476 100644
--- a/llvm/test/DebugInfo/X86/base-type-size.ll
+++ b/llvm/test/DebugInfo/X86/base-type-size.ll
@@ -12,6 +12,7 @@
; CHECK-NEXT: DW_AT_name ("DW_ATE_unsigned_1")
; CHECK-NEXT: DW_AT_encoding (DW_ATE_unsigned)
; CHECK-NEXT: DW_AT_byte_size (0x01)
+; CHECK-NEXT: DW_AT_bit_size (0x01)
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
>From efefb69d211416391f653e3bcd5afc3e4a000d62 Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Thu, 23 Oct 2025 13:18:54 +0100
Subject: [PATCH 3/6] Add/use DataSizeInBits (data_size) field to DIBasicType
---
a.bc | Bin 0 -> 1928 bytes
clang/lib/CodeGen/CGDebugInfo.cpp | 5 +-
clang/test/DebugInfo/Generic/bit-int.c | 6 +-
llvm/include/llvm/IR/DIBuilder.h | 7 +-
llvm/include/llvm/IR/DebugInfoMetadata.h | 78 ++++++++++++-------
llvm/lib/AsmParser/LLParser.cpp | 9 ++-
llvm/lib/Bitcode/Reader/MetadataLoader.cpp | 8 +-
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp | 1 +
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 6 +-
llvm/lib/IR/AsmWriter.cpp | 1 +
llvm/lib/IR/DIBuilder.cpp | 6 +-
llvm/lib/IR/DebugInfoMetadata.cpp | 15 ++--
llvm/lib/IR/LLVMContextImpl.h | 11 ++-
llvm/test/Bitcode/dbg-data-size-roundtrip.ll | 19 +++++
llvm/test/DebugInfo/bit-int-size.ll | 10 +--
15 files changed, 118 insertions(+), 64 deletions(-)
create mode 100644 a.bc
create mode 100644 llvm/test/Bitcode/dbg-data-size-roundtrip.ll
diff --git a/a.bc b/a.bc
new file mode 100644
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GIT binary patch
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diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 2ad187de16acc..5b15b9fddafc6 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1147,12 +1147,13 @@ llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
}
llvm::DIType *CGDebugInfo::CreateType(const BitIntType *Ty) {
-
StringRef Name = Ty->isUnsigned() ? "unsigned _BitInt" : "_BitInt";
llvm::dwarf::TypeKind Encoding = Ty->isUnsigned()
? llvm::dwarf::DW_ATE_unsigned
: llvm::dwarf::DW_ATE_signed;
- return DBuilder.createBasicType(Name, Ty->getNumBits(), Encoding);
+ return DBuilder.createBasicType(Name, CGM.getContext().getTypeSize(Ty),
+ Encoding, llvm::DINode::FlagZero, 0,
+ Ty->getNumBits());
}
llvm::DIType *CGDebugInfo::CreateType(const ComplexType *Ty) {
diff --git a/clang/test/DebugInfo/Generic/bit-int.c b/clang/test/DebugInfo/Generic/bit-int.c
index 16b3d7a2582c9..c6750834a15d8 100644
--- a/clang/test/DebugInfo/Generic/bit-int.c
+++ b/clang/test/DebugInfo/Generic/bit-int.c
@@ -1,8 +1,8 @@
// RUN: %clang_cc1 -x c++ %s -debug-info-kind=standalone -gno-column-info -emit-llvm -o - | FileCheck %s
// RUN: %clang_cc1 -x c %s -debug-info-kind=standalone -gno-column-info -emit-llvm -o - | FileCheck %s
-unsigned _BitInt(2) a;
+unsigned _BitInt(17) a;
_BitInt(2) b;
-// CHECK: !DIBasicType(name: "_BitInt", size: 2, encoding: DW_ATE_signed)
-// CHECK: !DIBasicType(name: "unsigned _BitInt", size: 2, encoding: DW_ATE_unsigned)
+// CHECK: !DIBasicType(name: "_BitInt", size: 8, data_size: 2, encoding: DW_ATE_signed)
+// CHECK: !DIBasicType(name: "unsigned _BitInt", size: 32, data_size: 17, encoding: DW_ATE_unsigned)
diff --git a/llvm/include/llvm/IR/DIBuilder.h b/llvm/include/llvm/IR/DIBuilder.h
index f3839c9694f34..4228ec9c3ef7a 100644
--- a/llvm/include/llvm/IR/DIBuilder.h
+++ b/llvm/include/llvm/IR/DIBuilder.h
@@ -209,10 +209,15 @@ namespace llvm {
/// \param NumExtraInhabitants The number of extra inhabitants of the type.
/// An extra inhabitant is a bit pattern that does not represent a valid
/// value for instances of a given type. This is used by the Swift language.
+ /// \param DataSizeInBits Optionally describes the number of bits used by
+ /// the value of the object when this is less than the storage size of
+ /// SizeInBits. Default value of zero indicates the object value and storage
+ /// sizes are equal.
LLVM_ABI DIBasicType *
createBasicType(StringRef Name, uint64_t SizeInBits, unsigned Encoding,
DINode::DIFlags Flags = DINode::FlagZero,
- uint32_t NumExtraInhabitants = 0);
+ uint32_t NumExtraInhabitants = 0,
+ uint32_t DataSizeInBits = 0);
/// Create debugging information entry for a binary fixed-point type.
/// \param Name Type name.
diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h
index c626efc9daaa4..ea7d7f95ff0d6 100644
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -891,96 +891,114 @@ class DIBasicType : public DIType {
friend class MDNode;
unsigned Encoding;
+ /// Describes the number of bits used by the value of the object Non-zero when
+ /// the value of an object does not fully occupy the storage size specified by
+ /// SizeInBits.
+ uint32_t DataSizeInBits;
protected:
DIBasicType(LLVMContext &C, StorageType Storage, unsigned Tag,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags,
- ArrayRef<Metadata *> Ops)
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ DIFlags Flags, ArrayRef<Metadata *> Ops)
: DIType(C, DIBasicTypeKind, Storage, Tag, 0, AlignInBits,
NumExtraInhabitants, Flags, Ops),
- Encoding(Encoding) {}
+ Encoding(Encoding), DataSizeInBits(DataSizeInBits) {}
DIBasicType(LLVMContext &C, unsigned ID, StorageType Storage, unsigned Tag,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags,
- ArrayRef<Metadata *> Ops)
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ DIFlags Flags, ArrayRef<Metadata *> Ops)
: DIType(C, ID, Storage, Tag, 0, AlignInBits, NumExtraInhabitants, Flags,
Ops),
- Encoding(Encoding) {}
+ Encoding(Encoding), DataSizeInBits(DataSizeInBits) {}
~DIBasicType() = default;
static DIBasicType *getImpl(LLVMContext &Context, unsigned Tag,
StringRef Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags,
+ uint32_t NumExtraInhabitants,
+ uint32_t DataSizeInBits, DIFlags Flags,
StorageType Storage, bool ShouldCreate = true) {
return getImpl(Context, Tag, getCanonicalMDString(Context, Name),
SizeInBits, AlignInBits, Encoding, NumExtraInhabitants,
- Flags, Storage, ShouldCreate);
+ DataSizeInBits, Flags, Storage, ShouldCreate);
}
static DIBasicType *getImpl(LLVMContext &Context, unsigned Tag,
MDString *Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags,
+ uint32_t NumExtraInhabitants,
+ uint32_t DataSizeInBits, DIFlags Flags,
StorageType Storage, bool ShouldCreate = true) {
auto *SizeInBitsNode = ConstantAsMetadata::get(
ConstantInt::get(Type::getInt64Ty(Context), SizeInBits));
return getImpl(Context, Tag, Name, SizeInBitsNode, AlignInBits, Encoding,
- NumExtraInhabitants, Flags, Storage, ShouldCreate);
+ NumExtraInhabitants, DataSizeInBits, Flags, Storage,
+ ShouldCreate);
}
- LLVM_ABI static DIBasicType *getImpl(LLVMContext &Context, unsigned Tag,
- MDString *Name, Metadata *SizeInBits,
- uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants,
- DIFlags Flags, StorageType Storage,
- bool ShouldCreate = true);
+ LLVM_ABI static DIBasicType *
+ getImpl(LLVMContext &Context, unsigned Tag, MDString *Name,
+ Metadata *SizeInBits, uint32_t AlignInBits, unsigned Encoding,
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits, DIFlags Flags,
+ StorageType Storage, bool ShouldCreate = true);
TempDIBasicType cloneImpl() const {
return getTemporary(getContext(), getTag(), getRawName(),
getRawSizeInBits(), getAlignInBits(), getEncoding(),
- getNumExtraInhabitants(), getFlags());
+ getNumExtraInhabitants(), getDataSizeInBits(),
+ getFlags());
}
public:
DEFINE_MDNODE_GET(DIBasicType, (unsigned Tag, StringRef Name),
- (Tag, Name, 0, 0, 0, 0, FlagZero))
+ (Tag, Name, 0, 0, 0, 0, 0, FlagZero))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, StringRef Name, uint64_t SizeInBits),
- (Tag, Name, SizeInBits, 0, 0, 0, FlagZero))
+ (Tag, Name, SizeInBits, 0, 0, 0, 0, FlagZero))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, MDString *Name, uint64_t SizeInBits),
- (Tag, Name, SizeInBits, 0, 0, 0, FlagZero))
+ (Tag, Name, SizeInBits, 0, 0, 0, 0, FlagZero))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, StringRef Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding, DIFlags Flags),
- (Tag, Name, SizeInBits, AlignInBits, Encoding, 0, Flags))
+ (Tag, Name, SizeInBits, AlignInBits, Encoding, 0, 0, Flags))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, MDString *Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding, DIFlags Flags),
- (Tag, Name, SizeInBits, AlignInBits, Encoding, 0, Flags))
+ (Tag, Name, SizeInBits, AlignInBits, Encoding, 0, 0, Flags))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, StringRef Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
uint32_t NumExtraInhabitants, DIFlags Flags),
(Tag, Name, SizeInBits, AlignInBits, Encoding,
- NumExtraInhabitants, Flags))
+ NumExtraInhabitants, 0, Flags))
+ DEFINE_MDNODE_GET(DIBasicType,
+ (unsigned Tag, StringRef Name, uint64_t SizeInBits,
+ uint32_t AlignInBits, unsigned Encoding,
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ DIFlags Flags),
+ (Tag, Name, SizeInBits, AlignInBits, Encoding,
+ NumExtraInhabitants, DataSizeInBits, Flags))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, MDString *Name, uint64_t SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags),
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ DIFlags Flags),
(Tag, Name, SizeInBits, AlignInBits, Encoding,
- NumExtraInhabitants, Flags))
+ NumExtraInhabitants, DataSizeInBits, Flags))
DEFINE_MDNODE_GET(DIBasicType,
(unsigned Tag, MDString *Name, Metadata *SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags),
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ DIFlags Flags),
(Tag, Name, SizeInBits, AlignInBits, Encoding,
- NumExtraInhabitants, Flags))
+ NumExtraInhabitants, DataSizeInBits, Flags))
TempDIBasicType clone() const { return cloneImpl(); }
unsigned getEncoding() const { return Encoding; }
+ uint32_t getDataSizeInBits() const { return DataSizeInBits; }
+
enum class Signedness { Signed, Unsigned };
/// Return the signedness of this type, or std::nullopt if this type is
@@ -1010,7 +1028,7 @@ class DIFixedPointType : public DIBasicType {
uint32_t AlignInBits, unsigned Encoding, DIFlags Flags,
unsigned Kind, int Factor, ArrayRef<Metadata *> Ops)
: DIBasicType(C, DIFixedPointTypeKind, Storage, Tag, AlignInBits,
- Encoding, 0, Flags, Ops),
+ Encoding, 0, 0, Flags, Ops),
Kind(Kind), Factor(Factor) {
assert(Kind == FixedPointBinary || Kind == FixedPointDecimal);
}
@@ -1019,7 +1037,7 @@ class DIFixedPointType : public DIBasicType {
unsigned Kind, APInt Numerator, APInt Denominator,
ArrayRef<Metadata *> Ops)
: DIBasicType(C, DIFixedPointTypeKind, Storage, Tag, AlignInBits,
- Encoding, 0, Flags, Ops),
+ Encoding, 0, 0, Flags, Ops),
Kind(Kind), Factor(0), Numerator(Numerator), Denominator(Denominator) {
assert(Kind == FixedPointRational);
}
@@ -1028,7 +1046,7 @@ class DIFixedPointType : public DIBasicType {
unsigned Kind, int Factor, APInt Numerator,
APInt Denominator, ArrayRef<Metadata *> Ops)
: DIBasicType(C, DIFixedPointTypeKind, Storage, Tag, AlignInBits,
- Encoding, 0, Flags, Ops),
+ Encoding, 0, 0, Flags, Ops),
Kind(Kind), Factor(Factor), Numerator(Numerator),
Denominator(Denominator) {}
~DIFixedPointType() = default;
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index cf6328580fd21..093f83d3de73a 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -5631,16 +5631,17 @@ bool LLParser::parseDIBasicType(MDNode *&Result, bool IsDistinct) {
OPTIONAL(name, MDStringField, ); \
OPTIONAL(size, MDUnsignedOrMDField, (0, UINT64_MAX)); \
OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX)); \
+ OPTIONAL(data_size, MDUnsignedField, (0, UINT32_MAX)); \
OPTIONAL(encoding, DwarfAttEncodingField, ); \
OPTIONAL(num_extra_inhabitants, MDUnsignedField, (0, UINT32_MAX)); \
OPTIONAL(flags, DIFlagField, );
PARSE_MD_FIELDS();
#undef VISIT_MD_FIELDS
- Result = GET_OR_DISTINCT(DIBasicType, (Context, tag.Val, name.Val,
- size.getValueAsMetadata(Context),
- align.Val, encoding.Val,
- num_extra_inhabitants.Val, flags.Val));
+ Result = GET_OR_DISTINCT(
+ DIBasicType,
+ (Context, tag.Val, name.Val, size.getValueAsMetadata(Context), align.Val,
+ encoding.Val, num_extra_inhabitants.Val, data_size.Val, flags.Val));
return false;
}
diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
index ed0443f599a44..2084ac187f5e6 100644
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -1531,7 +1531,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
break;
}
case bitc::METADATA_BASIC_TYPE: {
- if (Record.size() < 6 || Record.size() > 8)
+ if (Record.size() < 6 || Record.size() > 9)
return error("Invalid record");
IsDistinct = Record[0] & 1;
@@ -1540,13 +1540,13 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
? static_cast<DINode::DIFlags>(Record[6])
: DINode::FlagZero;
uint32_t NumExtraInhabitants = (Record.size() > 7) ? Record[7] : 0;
-
+ uint32_t DataSizeInBits = (Record.size() > 8) ? Record[8] : 0;
Metadata *SizeInBits = getMetadataOrConstant(SizeIsMetadata, Record[3]);
-
MetadataList.assignValue(
GET_OR_DISTINCT(DIBasicType,
(Context, Record[1], getMDString(Record[2]), SizeInBits,
- Record[4], Record[5], NumExtraInhabitants, Flags)),
+ Record[4], Record[5], NumExtraInhabitants,
+ DataSizeInBits, Flags)),
NextMetadataNo);
NextMetadataNo++;
break;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 8ff3aa9817571..cd9800ac81f33 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1925,6 +1925,7 @@ void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
Record.push_back(N->getEncoding());
Record.push_back(N->getFlags());
Record.push_back(N->getNumExtraInhabitants());
+ Record.push_back(N->getDataSizeInBits());
Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
Record.clear();
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 1253d9a463cbb..b832914a01637 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -773,9 +773,9 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIBasicType *BTy) {
// If the value of an object of the given type does not fully occupy the
// storage described by a byte size attribute, the base type entry may also
// have a DW_AT_bit_size [...] attribute.
- if (uint64_t SizeInBits = BTy->getSizeInBits();
- SizeInBits && SizeInBits % 8)
- addUInt(Buffer, dwarf::DW_AT_bit_size, std::nullopt, SizeInBits);
+ if (uint64_t DataSizeInBits = BTy->getDataSizeInBits();
+ DataSizeInBits && DataSizeInBits != SizeInBytes * 8)
+ addUInt(Buffer, dwarf::DW_AT_bit_size, std::nullopt, DataSizeInBits);
}
if (BTy->isBigEndian())
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index 3908a78f48412..df39dc4ef40ea 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -2199,6 +2199,7 @@ static void writeDIBasicType(raw_ostream &Out, const DIBasicType *N,
Printer.printString("name", N->getName());
Printer.printMetadataOrInt("size", N->getRawSizeInBits(), true);
Printer.printInt("align", N->getAlignInBits());
+ Printer.printInt("data_size", N->getDataSizeInBits());
Printer.printDwarfEnum("encoding", N->getEncoding(),
dwarf::AttributeEncodingString);
Printer.printInt("num_extra_inhabitants", N->getNumExtraInhabitants());
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 07a870f0630a5..ca11ecf2f473e 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -261,10 +261,12 @@ DIBasicType *DIBuilder::createNullPtrType() {
DIBasicType *DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
unsigned Encoding,
DINode::DIFlags Flags,
- uint32_t NumExtraInhabitants) {
+ uint32_t NumExtraInhabitants,
+ uint32_t DataSizeInBits) {
assert(!Name.empty() && "Unable to create type without name");
return DIBasicType::get(VMContext, dwarf::DW_TAG_base_type, Name, SizeInBits,
- 0, Encoding, NumExtraInhabitants, Flags);
+ 0, Encoding, NumExtraInhabitants, DataSizeInBits,
+ Flags);
}
DIFixedPointType *
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index e30df88e6b56b..fafc3254120de 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -872,15 +872,18 @@ DIEnumerator *DIEnumerator::getImpl(LLVMContext &Context, const APInt &Value,
DIBasicType *DIBasicType::getImpl(LLVMContext &Context, unsigned Tag,
MDString *Name, Metadata *SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, DIFlags Flags,
+ uint32_t NumExtraInhabitants,
+ uint32_t DataSizeInBits, DIFlags Flags,
StorageType Storage, bool ShouldCreate) {
assert(isCanonical(Name) && "Expected canonical MDString");
- DEFINE_GETIMPL_LOOKUP(DIBasicType, (Tag, Name, SizeInBits, AlignInBits,
- Encoding, NumExtraInhabitants, Flags));
+ DEFINE_GETIMPL_LOOKUP(DIBasicType,
+ (Tag, Name, SizeInBits, AlignInBits, Encoding,
+ NumExtraInhabitants, DataSizeInBits, Flags));
Metadata *Ops[] = {nullptr, nullptr, Name, SizeInBits, nullptr};
- DEFINE_GETIMPL_STORE(DIBasicType,
- (Tag, AlignInBits, Encoding, NumExtraInhabitants, Flags),
- Ops);
+ DEFINE_GETIMPL_STORE(
+ DIBasicType,
+ (Tag, AlignInBits, Encoding, NumExtraInhabitants, DataSizeInBits, Flags),
+ Ops);
}
std::optional<DIBasicType::Signedness> DIBasicType::getSignedness() const {
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index e03f993297e54..2c9921df0422e 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -480,20 +480,22 @@ template <> struct MDNodeKeyImpl<DIBasicType> {
uint32_t AlignInBits;
unsigned Encoding;
uint32_t NumExtraInhabitants;
+ uint32_t DataSizeInBits;
unsigned Flags;
MDNodeKeyImpl(unsigned Tag, MDString *Name, Metadata *SizeInBits,
uint32_t AlignInBits, unsigned Encoding,
- uint32_t NumExtraInhabitants, unsigned Flags)
+ uint32_t NumExtraInhabitants, uint32_t DataSizeInBits,
+ unsigned Flags)
: Tag(Tag), Name(Name), SizeInBits(SizeInBits), AlignInBits(AlignInBits),
Encoding(Encoding), NumExtraInhabitants(NumExtraInhabitants),
- Flags(Flags) {}
+ DataSizeInBits(DataSizeInBits), Flags(Flags) {}
MDNodeKeyImpl(const DIBasicType *N)
: Tag(N->getTag()), Name(N->getRawName()),
SizeInBits(N->getRawSizeInBits()), AlignInBits(N->getAlignInBits()),
Encoding(N->getEncoding()),
- NumExtraInhabitants(N->getNumExtraInhabitants()), Flags(N->getFlags()) {
- }
+ NumExtraInhabitants(N->getNumExtraInhabitants()),
+ DataSizeInBits(N->getDataSizeInBits()), Flags(N->getFlags()) {}
bool isKeyOf(const DIBasicType *RHS) const {
return Tag == RHS->getTag() && Name == RHS->getRawName() &&
@@ -501,6 +503,7 @@ template <> struct MDNodeKeyImpl<DIBasicType> {
AlignInBits == RHS->getAlignInBits() &&
Encoding == RHS->getEncoding() &&
NumExtraInhabitants == RHS->getNumExtraInhabitants() &&
+ DataSizeInBits == RHS->getDataSizeInBits() &&
Flags == RHS->getFlags();
}
diff --git a/llvm/test/Bitcode/dbg-data-size-roundtrip.ll b/llvm/test/Bitcode/dbg-data-size-roundtrip.ll
new file mode 100644
index 0000000000000..7c48e57cba4b2
--- /dev/null
+++ b/llvm/test/Bitcode/dbg-data-size-roundtrip.ll
@@ -0,0 +1,19 @@
+; RUN: opt %s -o - -S | llvm-as - | llvm-dis - | FileCheck %s
+
+; CHECK: !DIBasicType(name: "unsigned _BitInt", size: 32, data_size: 17, encoding: DW_ATE_unsigned)
+
+ at a = global i8 0, align 1, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!6, !7}
+!llvm.ident = !{!8}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 4, type: !5, isLocal: false, isDefinition: true)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 22.0.0git", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
+!3 = !DIFile(filename: "bit-int.c", directory: "/")
+!4 = !{!0}
+!5 = !DIBasicType(name: "unsigned _BitInt", size: 32, data_size: 17, encoding: DW_ATE_unsigned)
+!6 = !{i32 2, !"Debug Info Version", i32 3}
+!7 = !{i32 1, !"wchar_size", i32 4}
+!8 = !{!"clang version 22.0.0git"}
diff --git a/llvm/test/DebugInfo/bit-int-size.ll b/llvm/test/DebugInfo/bit-int-size.ll
index 69ab756f4e288..a076b1a75dbd2 100644
--- a/llvm/test/DebugInfo/bit-int-size.ll
+++ b/llvm/test/DebugInfo/bit-int-size.ll
@@ -7,11 +7,11 @@
; CHECK: DW_TAG_base_type
; CHECK-NEXT: DW_AT_name ("unsigned _BitInt")
; CHECK-NEXT: DW_AT_encoding (DW_ATE_unsigned)
-; CHECK-NEXT: DW_AT_byte_size (0x02)
-; CHECK-NEXT: DW_AT_bit_size (0x09)
+; CHECK-NEXT: DW_AT_byte_size (0x04)
+; CHECK-NEXT: DW_AT_bit_size (0x11)
; CHECK: DW_TAG_base_type
-; CHECK-NEXT: DW_AT_name ("unsigned _BitInt")
+; CHECK-NEXT: DW_AT_name ("_BitInt")
; CHECK-NEXT: DW_AT_encoding (DW_ATE_signed)
; CHECK-NEXT: DW_AT_byte_size (0x01)
; CHECK-NEXT: DW_AT_bit_size (0x02)
@@ -31,8 +31,8 @@
!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
!6 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !7, line: 5, type: !8, isLocal: false, isDefinition: true)
!7 = !DIFile(filename: "bit-int.c", directory: "/")
-!8 = !DIBasicType(name: "_BitInt", size: 2, encoding: DW_ATE_signed)
-!9 = !DIBasicType(name: "unsigned _BitInt", size: 2, encoding: DW_ATE_unsigned)
+!8 = !DIBasicType(name: "_BitInt", size: 8, data_size: 2, encoding: DW_ATE_signed)
+!9 = !DIBasicType(name: "unsigned _BitInt", size: 32, data_size: 17, encoding: DW_ATE_unsigned)
!10 = !{i32 2, !"Debug Info Version", i32 3}
!11 = !{i32 1, !"wchar_size", i32 4}
!12 = !{!"clang version 22.0.0git"}
>From 0531d6990c3f287f48c2fa3f4f79540e0c01450c Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Thu, 23 Oct 2025 14:16:26 +0100
Subject: [PATCH 4/6] undo change to base-type-size.ll
---
llvm/test/DebugInfo/X86/base-type-size.ll | 1 -
1 file changed, 1 deletion(-)
diff --git a/llvm/test/DebugInfo/X86/base-type-size.ll b/llvm/test/DebugInfo/X86/base-type-size.ll
index cb0c1eb63e476..3a8dc37bdc65f 100644
--- a/llvm/test/DebugInfo/X86/base-type-size.ll
+++ b/llvm/test/DebugInfo/X86/base-type-size.ll
@@ -12,7 +12,6 @@
; CHECK-NEXT: DW_AT_name ("DW_ATE_unsigned_1")
; CHECK-NEXT: DW_AT_encoding (DW_ATE_unsigned)
; CHECK-NEXT: DW_AT_byte_size (0x01)
-; CHECK-NEXT: DW_AT_bit_size (0x01)
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
>From 026976e2de84c3cec181a43832fd07a35fb86533 Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Wed, 29 Oct 2025 11:08:34 +0000
Subject: [PATCH 5/6] Remove DwarfCompileUnit change for DIExpression types
---
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 11 +++++------
llvm/test/DebugInfo/X86/base-type-size.ll | 3 +++
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 6f68548aa25f4..751d3735d3b2b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1793,14 +1793,13 @@ void DwarfCompileUnit::createBaseTypeDIEs() {
"_" + Twine(Btr.BitSize)).toStringRef(Str));
addUInt(Die, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1, Btr.Encoding);
// Round up to smallest number of bytes that contains this number of bits.
+ // ExprRefedBaseTypes is populated with types referenced by
+ // DW_OP_LLVM_convert operations in location expressions. These are often
+ // byte-sized, but one common counter-example is 1-bit sized conversions
+ // from `i1` types. TODO: Should these use DW_AT_bit_size? See
+ // DwarfUnit::constructTypeDIE.
addUInt(Die, dwarf::DW_AT_byte_size, std::nullopt,
divideCeil(Btr.BitSize, 8));
- // If the value of an object of the given type does not fully occupy the
- // storage described by a byte size attribute, the base type entry may also
- // have a DW_AT_bit_size [...] attribute.
- if (Btr.BitSize && (Btr.BitSize % 8))
- addUInt(Die, dwarf::DW_AT_bit_size, std::nullopt, Btr.BitSize);
-
Btr.Die = &Die;
}
}
diff --git a/llvm/test/DebugInfo/X86/base-type-size.ll b/llvm/test/DebugInfo/X86/base-type-size.ll
index 3a8dc37bdc65f..2f0ff2f60e95f 100644
--- a/llvm/test/DebugInfo/X86/base-type-size.ll
+++ b/llvm/test/DebugInfo/X86/base-type-size.ll
@@ -11,7 +11,10 @@
; CHECK: DW_TAG_base_type
; CHECK-NEXT: DW_AT_name ("DW_ATE_unsigned_1")
; CHECK-NEXT: DW_AT_encoding (DW_ATE_unsigned)
+;; TODO: Should this type use bit_size?
+; CHECK-NOT: DW_AT_bit_size
; CHECK-NEXT: DW_AT_byte_size (0x01)
+; CHECK-NOT: DW_AT_bit_size
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
>From a0bcf160300f800857a05b4950743128377ba84a Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hyams at sony.com>
Date: Wed, 29 Oct 2025 11:12:23 +0000
Subject: [PATCH 6/6] add TODO
---
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 2 ++
1 file changed, 2 insertions(+)
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index b832914a01637..555c56fd322bb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -773,6 +773,8 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIBasicType *BTy) {
// If the value of an object of the given type does not fully occupy the
// storage described by a byte size attribute, the base type entry may also
// have a DW_AT_bit_size [...] attribute.
+ // TODO: Do big endian targets need DW_AT_data_bit_offset? See discussion in
+ // pull request #164372.
if (uint64_t DataSizeInBits = BTy->getDataSizeInBits();
DataSizeInBits && DataSizeInBits != SizeInBytes * 8)
addUInt(Buffer, dwarf::DW_AT_bit_size, std::nullopt, DataSizeInBits);
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