llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang @llvm/pr-subscribers-clang-codegen Author: Florian Hahn (fhahn) <details> <summary>Changes</summary> At the moment,distinct fields for each union member are generated. When copying a union, we don't know which union member is active, so there's no benefit from recording the different fields. It can result in converting tbaa.struct fields to incorrect tbaa nodes when extracting fields. --- Full diff: https://github.com/llvm/llvm-project/pull/84370.diff 2 Files Affected: - (modified) clang/lib/CodeGen/CodeGenTBAA.cpp (+8) - (modified) clang/test/CodeGen/tbaa-struct.cpp (+3-5) ``````````diff diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index 8a081612193978..69fb1e11edc7dc 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -286,6 +286,14 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset, /* Things not handled yet include: C++ base classes, bitfields, */ if (const RecordType *TTy = QTy->getAs<RecordType>()) { + if (TTy->isUnionType()) { + uint64_t Size = Context.getTypeSizeInChars(QTy).getQuantity(); + llvm::MDNode *TBAAType = getChar(); + llvm::MDNode *TBAATag = getAccessTagInfo(TBAAAccessInfo(TBAAType, Size)); + Fields.push_back( + llvm::MDBuilder::TBAAStructField(BaseOffset, Size, TBAATag)); + return true; + } const RecordDecl *RD = TTy->getDecl()->getDefinition(); if (RD->hasFlexibleArrayMember()) return false; diff --git a/clang/test/CodeGen/tbaa-struct.cpp b/clang/test/CodeGen/tbaa-struct.cpp index 63e4097946448e..9b4b7415142d93 100644 --- a/clang/test/CodeGen/tbaa-struct.cpp +++ b/clang/test/CodeGen/tbaa-struct.cpp @@ -191,7 +191,7 @@ void copy12(UnionMember2 *a1, UnionMember2 *a2) { // (offset, size) = (0,1) char; (4,2) short; (8,4) int; (12,1) char; (16,4) int; (20,4) int // CHECK-OLD: [[TS2]] = !{i64 0, i64 1, !{{.*}}, i64 4, i64 2, !{{.*}}, i64 8, i64 4, !{{.*}}, i64 12, i64 1, !{{.*}}, i64 16, i64 4, {{.*}}, i64 20, i64 4, {{.*}}} // (offset, size) = (0,8) char; (0,2) char; (4,8) char -// CHECK-OLD: [[TS3]] = !{i64 0, i64 8, !{{.*}}, i64 0, i64 2, !{{.*}}, i64 4, i64 8, !{{.*}}} +// CHECK-OLD: [[TS3]] = !{i64 0, i64 12, [[TAG_CHAR]]} // 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 2, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE:!.+]]} @@ -199,10 +199,8 @@ void copy12(UnionMember2 *a1, UnionMember2 *a2) { // CHECK-OLD [[DOUBLE]] = !{!"double", [[CHAR]], i64 0} // CHECK-OLD: [[TS7]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]], i64 3, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]], i64 16, i64 1, [[TAG_CHAR]]} // CHECK-OLD: [[TS8]] = !{i64 0, i64 4, [[TAG_CHAR]], i64 8, i64 8, [[TAG_DOUBLE]]} -// CHECK-OLD: [[TS9]] = !{i64 0, i64 8, [[TAG_DOUBLE]], i64 0, i64 4, [[TAG_FLOAT:!.+]], i64 8, i64 4, [[TAG_INT]]} -// CHECK-OLD: [[TAG_FLOAT]] = !{[[FLOAT:!.+]], [[FLOAT]], i64 0} -// CHECK-OLD: [[FLOAT]] = !{!"float", [[CHAR]], i64 0} -// CHECK-OLD: [[TS10]] = !{i64 0, i64 4, [[TAG_INT]], i64 8, i64 8, [[TAG_DOUBLE]], i64 8, i64 4, [[TAG_FLOAT:!.+]]} +// CHECK-OLD: [[TS9]] = !{i64 0, i64 8, [[TAG_CHAR]], i64 8, i64 4, [[TAG_INT]]} +// CHECK-OLD: [[TS10]] = !{i64 0, i64 4, [[TAG_INT]], i64 8, i64 8, [[TAG_CHAR]]} // CHECK-NEW-DAG: [[TYPE_char:!.*]] = !{{{.*}}, i64 1, !"omnipotent char"} // CHECK-NEW-DAG: [[TAG_char]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0} `````````` </details> https://github.com/llvm/llvm-project/pull/84370 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
