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Fix DWARF generation for enums

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The DWARF generated for Rust enums was always somewhat unusual.
Rather than using DWARF constructs directly, it would emit magic field
names like "RUST$ENCODED$ENUM$0$Name" and "RUST$ENUM$DISR".  Since
PR #45225, though, even this has not worked -- the ad hoc scheme was
not updated to handle the wider variety of niche-filling layout
optimizations now available.

This patch changes the generated DWARF to use the standard tags meant
for this purpose; namely, DW_TAG_variant and DW_TAG_variant_part.

The patch to implement this went in to LLVM 7.  In order to work with
older versions of LLVM, and because LLVM doesn't do anything here for
PDB, the existing code is kept as a fallback mode.

Support for this DWARF is in the Rust lldb and in gdb 8.2.

Closes #32920
Closes #32924
Closes #52762
Closes #53153
This commit is contained in:
Tom Tromey 2017-11-29 14:42:25 -07:00
parent e8aef7cae1
commit 71ce4c3007
5 changed files with 494 additions and 147 deletions
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49
src/rustllvm/RustWrapper.cpp
View file

@ -713,6 +713,21 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStructType(
unwrapDI<DIType>(VTableHolder), UniqueId));
}
extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantPart(
LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
uint32_t AlignInBits, LLVMRustDIFlags Flags, LLVMMetadataRef Discriminator,
LLVMMetadataRef Elements, const char *UniqueId) {
#if LLVM_VERSION_GE(7, 0)
return wrap(Builder->createVariantPart(
unwrapDI<DIDescriptor>(Scope), Name, unwrapDI<DIFile>(File), LineNumber,
SizeInBits, AlignInBits, fromRust(Flags), unwrapDI<DIDerivedType>(Discriminator),
DINodeArray(unwrapDI<MDTuple>(Elements)), UniqueId));
#else
abort();
#endif
}
extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateMemberType(
LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
LLVMMetadataRef File, unsigned LineNo, uint64_t SizeInBits,
@ -724,6 +739,28 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateMemberType(
fromRust(Flags), unwrapDI<DIType>(Ty)));
}
extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantMemberType(
LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
const char *Name, LLVMMetadataRef File, unsigned LineNo, uint64_t SizeInBits,
uint32_t AlignInBits, uint64_t OffsetInBits, LLVMValueRef Discriminant,
LLVMRustDIFlags Flags, LLVMMetadataRef Ty) {
#if LLVM_VERSION_GE(7, 0)
llvm::ConstantInt* D = nullptr;
if (Discriminant) {
D = unwrap<llvm::ConstantInt>(Discriminant);
}
return wrap(Builder->createVariantMemberType(unwrapDI<DIDescriptor>(Scope), Name,
unwrapDI<DIFile>(File), LineNo,
SizeInBits, AlignInBits, OffsetInBits, D,
fromRust(Flags), unwrapDI<DIType>(Ty)));
#else
return wrap(Builder->createMemberType(unwrapDI<DIDescriptor>(Scope), Name,
unwrapDI<DIFile>(File), LineNo,
SizeInBits, AlignInBits, OffsetInBits,
fromRust(Flags), unwrapDI<DIType>(Ty)));
#endif
}
extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateLexicalBlock(
LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope,
LLVMMetadataRef File, unsigned Line, unsigned Col) {
@ -826,11 +863,19 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerationType(
LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
uint32_t AlignInBits, LLVMMetadataRef Elements,
LLVMMetadataRef ClassTy) {
LLVMMetadataRef ClassTy, bool IsFixed) {
#if LLVM_VERSION_GE(7, 0)
return wrap(Builder->createEnumerationType(
unwrapDI<DIDescriptor>(Scope), Name, unwrapDI<DIFile>(File), LineNumber,
SizeInBits, AlignInBits, DINodeArray(unwrapDI<MDTuple>(Elements)),
unwrapDI<DIType>(ClassTy)));
unwrapDI<DIType>(ClassTy), "", IsFixed));
#else
// Ignore IsFixed on older LLVM.
return wrap(Builder->createEnumerationType(
unwrapDI<DIDescriptor>(Scope), Name, unwrapDI<DIFile>(File), LineNumber,
SizeInBits, AlignInBits, DINodeArray(unwrapDI<MDTuple>(Elements)),
unwrapDI<DIType>(ClassTy), ""));
#endif
}
extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateUnionType(