https://github.com/resistor updated https://github.com/llvm/llvm-project/pull/125448
>From 8d2ed55358510e45c03934aaaffccbf12d0bffce Mon Sep 17 00:00:00 2001 From: Owen Anderson <resis...@mac.com> Date: Mon, 3 Feb 2025 15:41:20 +1300 Subject: [PATCH] [clang] Do not emit template parameter objects as COMDATs when they have internal linkage. Per the ELF spec, section groups may only contain local symbols if those symbols are only referenced from within the section group. [1] In the case of template parameter objects, they can be referenced from outside the group when the type of the object was declared in an anonymous namespace. In that case, we can't place the object in a COMDAT. This matches GCC's linkage behavior on the test input. [1]: https://www.sco.com/developers/gabi/latest/ch4.sheader.html#section_groups --- clang/lib/CodeGen/CodeGenModule.cpp | 2 +- clang/test/CodeGenCXX/template-param-objects.cpp | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 05879cd486a8c9..82002b8d8e4d4f 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -3765,7 +3765,7 @@ ConstantAddress CodeGenModule::GetAddrOfTemplateParamObject( auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(), /*isConstant=*/true, Linkage, Init, Name); setGVProperties(GV, TPO); - if (supportsCOMDAT()) + if (supportsCOMDAT() && Linkage == llvm::GlobalValue::LinkOnceODRLinkage) GV->setComdat(TheModule.getOrInsertComdat(GV->getName())); Emitter.finalize(GV); diff --git a/clang/test/CodeGenCXX/template-param-objects.cpp b/clang/test/CodeGenCXX/template-param-objects.cpp index 11ebd21521e83b..ff6acc438d137a 100644 --- a/clang/test/CodeGenCXX/template-param-objects.cpp +++ b/clang/test/CodeGenCXX/template-param-objects.cpp @@ -5,6 +5,9 @@ struct S { char buf[32]; }; template<S s> constexpr const char *begin() { return s.buf; } template<S s> constexpr const char *end() { return s.buf + __builtin_strlen(s.buf); } +namespace { struct T { char buf[32]; }; } +template<T t> constexpr const char* begin_anon() { return t.buf; } + // ITANIUM: [[HELLO:@_ZTAXtl1StlA32_cLc104ELc101ELc108ELc108ELc111ELc32ELc119ELc111ELc114ELc108ELc100EEEE]] // MSABI: [[HELLO:@"[?][?]__N2US@@3D0GI@@0GF@@0GM@@0GM@@0GP@@0CA@@0HH@@0GP@@0HC@@0GM@@0GE@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@0A@@@@@"]] // ITANIUM-SAME: = linkonce_odr constant { <{ [11 x i8], [21 x i8] }> } { <{ [11 x i8], [21 x i8] }> <{ [11 x i8] c"hello world", [21 x i8] zeroinitializer }> }, comdat @@ -19,3 +22,10 @@ const char *p = begin<S{"hello world"}>(); // MSABI: @"?q@@3PEBDEB" // CHECK-SAME: global ptr getelementptr (i8, ptr [[HELLO]], i64 11) const char *q = end<S{"hello world"}>(); + + +// CHECK: internal constant { <{ [10 x i8], [22 x i8] }> } { <{ [10 x i8], [22 x i8] }> <{ [10 x i8] c"hello anon", [22 x i8] zeroinitializer }> } +// CHECK-NOT: comdat +// ITANIUM: @r +// MSABI: @"?r@@3PEBDEB" +const char *r = begin_anon<T{"hello anon"}>(); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
