On 22/01/2014 23:07, Richard Smith wrote:
Author: rsmith
Date: Wed Jan 22 17:07:19 2014
New Revision: 199850
URL: http://llvm.org/viewvc/llvm-project?rev=199850&view=rev
Log:
Don't forget about a builtin if we're about to redeclare it and we couldn't
create an implicit declaration of it (because some type it depends on is
unavailable). This had the effect of causing us to not implicitly give it the
right attributes. It turns out that glibc's __sigsetjmp is declared before
sigjmp_buf is declared, and this resulted in us not implicitly giving it
__attribute__((returns_twice)), which in turn resulted in miscompiles in any C
code calling glibc's sigsetjmp.
Do you suppose we should provide a DefaultIgnore warning for
ForgetBuiltin to assist system header developers? It looks a bit
hit-and-miss at the moment.
Alp.
(See also the vaguely-related sourceware.org/PR4662.)
Modified:
cfe/trunk/lib/Sema/SemaLookup.cpp
cfe/trunk/test/Sema/implicit-builtin-decl.c
Modified: cfe/trunk/lib/Sema/SemaLookup.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=199850&r1=199849&r2=199850&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaLookup.cpp (original)
+++ cfe/trunk/lib/Sema/SemaLookup.cpp Wed Jan 22 17:07:19 2014
@@ -545,14 +545,6 @@ static bool LookupBuiltin(Sema &S, Looku
R.addDecl(D);
return true;
}
-
- if (R.isForRedeclaration()) {
- // If we're redeclaring this function anyway, forget that
- // this was a builtin at all.
- S.Context.BuiltinInfo.ForgetBuiltin(BuiltinID, S.Context.Idents);
- }
-
- return false;
}
}
}
Modified: cfe/trunk/test/Sema/implicit-builtin-decl.c
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/implicit-builtin-decl.c?rev=199850&r1=199849&r2=199850&view=diff
==============================================================================
--- cfe/trunk/test/Sema/implicit-builtin-decl.c (original)
+++ cfe/trunk/test/Sema/implicit-builtin-decl.c Wed Jan 22 17:07:19 2014
@@ -1,4 +1,6 @@
// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: not %clang_cc1 -fsyntax-only -ast-dump %s | FileCheck %s
+
void f() {
int *ptr = malloc(sizeof(int) * 10); // expected-warning{{implicitly
declaring library function 'malloc' with type}} \
// expected-note{{please include the header <stdlib.h> or explicitly
provide a declaration for 'malloc'}} \
@@ -57,3 +59,10 @@ void snprintf() { }
void longjmp(); // expected-warning{{declaration of built-in function 'longjmp'
requires inclusion of the header <setjmp.h>}}
extern float fmaxf(float, float);
+
+struct __jmp_buf_tag {};
+void sigsetjmp(struct __jmp_buf_tag[1], int); // expected-warning{{declaration of
built-in function 'sigsetjmp' requires inclusion of the header <setjmp.h>}}
+
+// CHECK: FunctionDecl {{.*}} <line:[[@LINE-2]]:1, col:44> sigsetjmp '
+// CHECK-NOT: FunctionDecl
+// CHECK: ReturnsTwiceAttr {{.*}} <{{.*}}> Implicit
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