https://github.com/fhahn updated https://github.com/llvm/llvm-project/pull/82922
>From 556fcefed9645aa0a0a965ff8f22d8accdf9eefc Mon Sep 17 00:00:00 2001 From: Florian Hahn <f...@fhahn.com> Date: Sun, 25 Feb 2024 13:23:17 +0000 Subject: [PATCH 1/2] [TBAA] Skip all bitfields when generating !tbaa.struct metadata. At the moment, clang generates what I believe are incorrect !tbaa.struct fields for named bitfields. At the moment, the base type size is used for named bifields (e.g. sizeof(int)) instead of the bifield width per field. This results in overalpping fields in !tbaa.struct metadata. This causes incorrect results when extracting individual copied fields from !tbaa.struct as in added in dc85719d5. This patch fixes that by skipping all bitfields, not only unnamed ones (note that CollectFields has a TODO to support bitfields). As bitfields specify their widths in bits, while !tbaa metadata uses bytes for sizes and offsets, I don't think we would be able to generate correct metadata for them in general. If this understanding is correct, I can also extend the verifier to check that !tbaa.struct fields aren't overlapping. Fixes https://github.com/llvm/llvm-project/issues/82586 --- clang/lib/CodeGen/CodeGenTBAA.cpp | 2 +- clang/test/CodeGen/tbaa-struct.cpp | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index dc288bc3f6157a..43a1aee3d73823 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -298,7 +298,7 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset, unsigned idx = 0; for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i, ++idx) { - if ((*i)->isZeroSize(Context) || (*i)->isUnnamedBitfield()) + if ((*i)->isZeroSize(Context) || (*i)->isBitField()) continue; uint64_t Offset = BaseOffset + Layout.getFieldOffset(idx) / Context.getCharWidth(); diff --git a/clang/test/CodeGen/tbaa-struct.cpp b/clang/test/CodeGen/tbaa-struct.cpp index ff5521fcf3f604..17c9d6bf6a7260 100644 --- a/clang/test/CodeGen/tbaa-struct.cpp +++ b/clang/test/CodeGen/tbaa-struct.cpp @@ -130,7 +130,7 @@ void copy8(NamedBitfields *a1, NamedBitfields *a2) { // CHECK-OLD: [[TS3]] = !{i64 0, i64 8, !{{.*}}, i64 0, i64 2, !{{.*}}, i64 4, i64 8, !{{.*}}} // CHECK-OLD: [[TS4]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]]} // CHECK-OLD: [[TS5]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 5, i64 1, [[TAG_CHAR]]} -// CHECK-OLD: [[TS6]] = !{i64 0, i64 4, [[TAG_INT]], i64 1, i64 4, [[TAG_INT]], i64 2, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE:!.+]]} +// CHECK-OLD: [[TS6]] = !{i64 2, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE:!.+]]} // CHECK-OLD: [[TAG_DOUBLE]] = !{[[DOUBLE:!.+]], [[DOUBLE]], i64 0} // CHECK-OLD [[DOUBLE]] = !{!"double", [[CHAR]], i64 0} >From 32be3b7d944fc5da50add4b6fea551ba6c9d428c Mon Sep 17 00:00:00 2001 From: Florian Hahn <f...@fhahn.com> Date: Mon, 26 Feb 2024 10:19:57 +0000 Subject: [PATCH 2/2] WIP use CGBitFieldInfo. --- clang/lib/CodeGen/CodeGenModule.cpp | 2 +- clang/lib/CodeGen/CodeGenTBAA.cpp | 33 +++++++++++++++++++++++------ clang/lib/CodeGen/CodeGenTBAA.h | 4 +++- 3 files changed, 31 insertions(+), 8 deletions(-) diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 95e457bef28ed3..ed8db055723024 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -397,7 +397,7 @@ CodeGenModule::CodeGenModule(ASTContext &C, // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0. if (LangOpts.Sanitize.has(SanitizerKind::Thread) || (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0)) - TBAA.reset(new CodeGenTBAA(Context, TheModule, CodeGenOpts, getLangOpts(), + TBAA.reset(new CodeGenTBAA(Context, getTypes(), TheModule, CodeGenOpts, getLangOpts(), getCXXABI().getMangleContext())); // If debug info or coverage generation is enabled, create the CGDebugInfo diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index 43a1aee3d73823..6a453bb1144582 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -14,6 +14,8 @@ // //===----------------------------------------------------------------------===// +#include "CGRecordLayout.h" +#include "CodeGenTypes.h" #include "CodeGenTBAA.h" #include "clang/AST/ASTContext.h" #include "clang/AST/Attr.h" @@ -29,10 +31,10 @@ using namespace clang; using namespace CodeGen; -CodeGenTBAA::CodeGenTBAA(ASTContext &Ctx, llvm::Module &M, +CodeGenTBAA::CodeGenTBAA(ASTContext &Ctx, CodeGenTypes &CGTypes, llvm::Module &M, const CodeGenOptions &CGO, const LangOptions &Features, MangleContext &MContext) - : Context(Ctx), Module(M), CodeGenOpts(CGO), + : Context(Ctx), CGTypes(CGTypes), Module(M), CodeGenOpts(CGO), Features(Features), MContext(MContext), MDHelper(M.getContext()), Root(nullptr), Char(nullptr) {} @@ -294,18 +296,37 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset, return false; const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); + const CGRecordLayout &CGRL = CGTypes.getCGRecordLayout(RD); unsigned idx = 0; for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i, ++idx) { - if ((*i)->isZeroSize(Context) || (*i)->isBitField()) + if ((*i)->isZeroSize(Context)) continue; + uint64_t Offset = BaseOffset + Layout.getFieldOffset(idx) / Context.getCharWidth(); QualType FieldQTy = i->getType(); - if (!CollectFields(Offset, FieldQTy, Fields, - MayAlias || TypeHasMayAlias(FieldQTy))) - return false; + if ((*i)->isBitField()) { + RecordDecl::field_iterator j = i; + unsigned CurrentBitFieldSize = 0; + while (j != e && (*j)->isBitField()) { + const CGBitFieldInfo &Info = CGRL.getBitFieldInfo(*j); + CurrentBitFieldSize += Info.Size; + j++; + } + uint64_t Offset = BaseOffset; + uint64_t Size = llvm::divideCeil(CurrentBitFieldSize , 8); + llvm::MDNode *TBAAType = getChar(); + llvm::MDNode *TBAATag = getAccessTagInfo(TBAAAccessInfo(TBAAType, Size)); + Fields.push_back(llvm::MDBuilder::TBAAStructField(Offset, Size, TBAATag)); + i = std::prev(j); + } else { + if (!CollectFields(Offset, FieldQTy, Fields, + MayAlias || TypeHasMayAlias(FieldQTy))) + return false; + + } } return true; } diff --git a/clang/lib/CodeGen/CodeGenTBAA.h b/clang/lib/CodeGen/CodeGenTBAA.h index a65963596fe9de..7e315c285be389 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.h +++ b/clang/lib/CodeGen/CodeGenTBAA.h @@ -29,6 +29,7 @@ namespace clang { class Type; namespace CodeGen { + class CodeGenTypes; // TBAAAccessKind - A kind of TBAA memory access descriptor. enum class TBAAAccessKind : unsigned { @@ -115,6 +116,7 @@ struct TBAAAccessInfo { /// while lowering AST types to LLVM types. class CodeGenTBAA { ASTContext &Context; + CodeGenTypes &CGTypes; llvm::Module &Module; const CodeGenOptions &CodeGenOpts; const LangOptions &Features; @@ -167,7 +169,7 @@ class CodeGenTBAA { llvm::MDNode *getBaseTypeInfoHelper(const Type *Ty); public: - CodeGenTBAA(ASTContext &Ctx, llvm::Module &M, const CodeGenOptions &CGO, + CodeGenTBAA(ASTContext &Ctx, CodeGenTypes &CGTypes, llvm::Module &M, const CodeGenOptions &CGO, const LangOptions &Features, MangleContext &MContext); ~CodeGenTBAA(); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
