From 37dec10dbc58f0da9b90861aa04d11ae0ed39935 Mon Sep 17 00:00:00 2001 From: Manman Ren Date: Thu, 11 Feb 2016 19:19:18 +0000 Subject: [PATCH] [PR26550] Use a different TBAA root for C++ vs C. This commit changes the root from "Simple C/C++ TBAA" to "Simple C++ TBAA" for C++. The problem is that the type name in the TBAA nodes is generated differently for C vs C++. If we link an IR file for C with an IR file for C++, since they have the same root and the type names are different, accesses to the two type nodes will be considered no-alias, even though the two type nodes are from the same type in a header file. The fix is to use different roots for C and C++. Types from C will be treated conservatively in respect to types from C++. Follow-up commits will change the C root to "Simple C TBAA" plus some mangling change for C types to make it a little more aggresive. llvm-svn: 260567 --- clang/lib/CodeGen/CodeGenTBAA.cpp | 8 ++++++-- clang/test/CodeGen/tbaa-class.cpp | 2 +- clang/test/CodeGen/tbaa-for-vptr.cpp | 2 +- clang/test/CodeGen/tbaa.cpp | 2 +- 4 files changed, 9 insertions(+), 5 deletions(-) diff --git a/clang/lib/CodeGen/CodeGenTBAA.cpp b/clang/lib/CodeGen/CodeGenTBAA.cpp index c3c925cde2fd..04224e726797 100644 --- a/clang/lib/CodeGen/CodeGenTBAA.cpp +++ b/clang/lib/CodeGen/CodeGenTBAA.cpp @@ -44,8 +44,12 @@ llvm::MDNode *CodeGenTBAA::getRoot() { // if our LLVM IR is linked with LLVM IR from a different front-end // (or a different version of this front-end), their TBAA trees will // remain distinct, and the optimizer will treat them conservatively. - if (!Root) - Root = MDHelper.createTBAARoot("Simple C/C++ TBAA"); + if (!Root) { + if (Features.CPlusPlus) + Root = MDHelper.createTBAARoot("Simple C++ TBAA"); + else + Root = MDHelper.createTBAARoot("Simple C/C++ TBAA"); + } return Root; } diff --git a/clang/test/CodeGen/tbaa-class.cpp b/clang/test/CodeGen/tbaa-class.cpp index f611ae5abb88..7172e05d9e34 100644 --- a/clang/test/CodeGen/tbaa-class.cpp +++ b/clang/test/CodeGen/tbaa-class.cpp @@ -199,7 +199,7 @@ uint32_t g12(StructC *C, StructD *D, uint64_t count) { } // CHECK: [[TYPE_char:!.*]] = !{!"omnipotent char", [[TAG_cxx_tbaa:!.*]], -// CHECK: [[TAG_cxx_tbaa]] = !{!"Simple C/C++ TBAA"} +// CHECK: [[TAG_cxx_tbaa]] = !{!"Simple C++ TBAA"} // CHECK: [[TAG_i32]] = !{[[TYPE_i32:!.*]], [[TYPE_i32]], i64 0} // CHECK: [[TYPE_i32]] = !{!"int", [[TYPE_char]], // CHECK: [[TAG_i16]] = !{[[TYPE_i16:!.*]], [[TYPE_i16]], i64 0} diff --git a/clang/test/CodeGen/tbaa-for-vptr.cpp b/clang/test/CodeGen/tbaa-for-vptr.cpp index 35e95a54dab2..7b8ae2099e47 100644 --- a/clang/test/CodeGen/tbaa-for-vptr.cpp +++ b/clang/test/CodeGen/tbaa-for-vptr.cpp @@ -32,4 +32,4 @@ void CallFoo(A *a, int (A::*fp)() const) { // // CHECK: [[NUM]] = !{[[TYPE:!.*]], [[TYPE]], i64 0} // CHECK: [[TYPE]] = !{!"vtable pointer", !{{.*}} -// NOTBAA-NOT: = !{!"Simple C/C++ TBAA"} +// NOTBAA-NOT: = !{!"Simple C++ TBAA"} diff --git a/clang/test/CodeGen/tbaa.cpp b/clang/test/CodeGen/tbaa.cpp index c43ca58bc3f6..f98c46f1497b 100644 --- a/clang/test/CodeGen/tbaa.cpp +++ b/clang/test/CodeGen/tbaa.cpp @@ -237,7 +237,7 @@ uint32_t g15(StructS *S, StructS3 *S3, uint64_t count) { } // CHECK: [[TYPE_char:!.*]] = !{!"omnipotent char", [[TAG_cxx_tbaa:!.*]], -// CHECK: [[TAG_cxx_tbaa]] = !{!"Simple C/C++ TBAA"} +// CHECK: [[TAG_cxx_tbaa]] = !{!"Simple C++ TBAA"} // CHECK: [[TAG_i32]] = !{[[TYPE_i32:!.*]], [[TYPE_i32]], i64 0} // CHECK: [[TYPE_i32]] = !{!"int", [[TYPE_char]], // CHECK: [[TAG_i16]] = !{[[TYPE_i16:!.*]], [[TYPE_i16]], i64 0}