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Fix evatuated value of __builtin_object_size according to its 

'type'  argument when it cannot be determined which objects ptr 
points to at compile time. rdar://18334276

llvm-svn: 218258
This commit is contained in:
Fariborz Jahanian 2014-09-22 17:11:59 +00:00
parent 9f73851e39
commit a3d8879be7
2 changed files with 31 additions and 2 deletions
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16
clang/lib/AST/ExprConstant.cpp
View File

@ -6052,8 +6052,20 @@ bool IntExprEvaluator::TryEvaluateBuiltinObjectSize(const CallExpr *E) {
return false;
}
// If we can prove the base is null, lower to zero now.
if (!Base.getLValueBase()) return Success(0, E);
if (!Base.getLValueBase()) {
// It is not possible to determine which objects ptr points to at compile time,
// __builtin_object_size should return (size_t) -1 for type 0 or 1
// and (size_t) 0 for type 2 or 3.
llvm::APSInt TypeIntVaue;
const Expr *ExprType = E->getArg(1);
if (!ExprType->EvaluateAsInt(TypeIntVaue, Info.Ctx))
return false;
if (TypeIntVaue == 0 || TypeIntVaue == 1)
return Success(-1, E);
if (TypeIntVaue == 2 || TypeIntVaue == 3)
return Success(0, E);
return Error(E);
}
QualType T = GetObjectType(Base.getLValueBase());
if (T.isNull() ||

17
clang/test/Sema/builtin-object-size.c
View File

@ -26,3 +26,20 @@ void f4(const char *fmt, ...) {
__builtin___vsnprintf_chk (0, 42, 0, 11, fmt, args); // expected-warning {{'__builtin___vsnprintf_chk' will always overflow destination buffer}}
}
// rdar://18334276
typedef unsigned long size_t;
void * memcset(void *restrict dst, int src, size_t n);
void * memcpy(void *restrict dst, const void *restrict src, size_t n);
#define memset(dest, src, len) __builtin___memset_chk(dest, src, len, __builtin_object_size(dest, 0))
#define memcpy(dest, src, len) __builtin___memcpy_chk(dest, src, len, __builtin_object_size(dest, 0))
#define memcpy1(dest, src, len) __builtin___memcpy_chk(dest, src, len, __builtin_object_size(dest, 4))
#define NULL ((void *)0)
void f5(void)
{
char buf[10];
memset((void *)0x100000000ULL, 0, 0x1000);
memcpy((char *)NULL + 0x10000, buf, 0x10);
memcpy1((char *)NULL + 0x10000, buf, 0x10); // expected-error {{argument should be a value from 0 to 3}}
}