Author: mren
Date: Thu Feb 11 13:19:18 2016
New Revision: 260567
URL: http://llvm.org/viewvc/llvm-project?rev=260567&view=rev
Log:
[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.
Modified:
cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp
cfe/trunk/test/CodeGen/tbaa-class.cpp
cfe/trunk/test/CodeGen/tbaa-for-vptr.cpp
cfe/trunk/test/CodeGen/tbaa.cpp
Modified: cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp?rev=260567&r1=260566&r2=260567&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenTBAA.cpp Thu Feb 11 13:19:18 2016
@@ -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;
}
Modified: cfe/trunk/test/CodeGen/tbaa-class.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/tbaa-class.cpp?rev=260567&r1=260566&r2=260567&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/tbaa-class.cpp (original)
+++ cfe/trunk/test/CodeGen/tbaa-class.cpp Thu Feb 11 13:19:18 2016
@@ -199,7 +199,7 @@ uint32_t g12(StructC *C, StructD *D, uin
}
// 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}
Modified: cfe/trunk/test/CodeGen/tbaa-for-vptr.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/tbaa-for-vptr.cpp?rev=260567&r1=260566&r2=260567&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/tbaa-for-vptr.cpp (original)
+++ cfe/trunk/test/CodeGen/tbaa-for-vptr.cpp Thu Feb 11 13:19:18 2016
@@ -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"}
Modified: cfe/trunk/test/CodeGen/tbaa.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/tbaa.cpp?rev=260567&r1=260566&r2=260567&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/tbaa.cpp (original)
+++ cfe/trunk/test/CodeGen/tbaa.cpp Thu Feb 11 13:19:18 2016
@@ -237,7 +237,7 @@ uint32_t g15(StructS *S, StructS3 *S3, u
}
// 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}
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