This fixes an assertion failure in cases where we had expression
statements that declared variables nested inside of pass_object_size
args. Since we were emitting the same ExprStmt twice (once for the arg,
once for the @llvm.objectsize call), we were getting issues with
redefining locals.
This also means that we can be more lax about when we emit
@llvm.objectsize for pass_object_size args: since we're reusing the
arg's value itself, we don't have to care so much about side-effects.
llvm-svn: 295935
The following code would crash clang:
void foo(unsigned *const __attribute__((pass_object_size(0))));
void bar(unsigned *i) { foo(i); }
This is because we were always selecting the version of
`@llvm.objectsize` that takes an i8* in CodeGen. Passing an i32* as an
i8* makes LLVM very unhappy.
(Yes, I'm surprised that this remained uncaught for so long, too. :) )
As an added bonus, we'll now also use the appropriate address space when
emitting @llvm.objectsize calls.
llvm-svn: 295805
This patch makes us act more conservatively when trying to determine
the objectsize for an array at the end of an object. This is in
response to code like the following:
```
struct sockaddr {
/* snip */
char sa_data[14];
};
void foo(const char *s) {
size_t slen = strlen(s) + 1;
size_t added_len = slen <= 14 ? 0 : slen - 14;
struct sockaddr *sa = malloc(sizeof(struct sockaddr) + added_len);
strcpy(sa->sa_data, s);
// ...
}
```
`__builtin_object_size(sa->sa_data, 1)` would return 14, when there
could be more than 14 bytes at `sa->sa_data`.
Code like this is apparently not uncommon. FreeBSD's manual even
explicitly mentions this pattern:
https://www.freebsd.org/doc/en/books/developers-handbook/sockets-essential-functions.html
(section 7.5.1.1.2).
In light of this, we now just give up on any array at the end of an
object if we can't find the object's initial allocation.
I lack numbers for how much more conservative we actually become as a
result of this change, so I chose the fix that would make us as
compatible with GCC as possible. If we want to be more aggressive, I'm
happy to consider some kind of whitelist or something instead.
llvm-svn: 281277
This patch fixes a bug where we'd segfault (in some cases) if we saw a
variadic function with one or more pass_object_size arguments.
Differential Revision: http://reviews.llvm.org/D17462
llvm-svn: 272971
These additions were meant to go in as a part of r254554; while it's
certainly nice to have new functionality, it's nicer if we have tests to
go with it. :)
llvm-svn: 254632
George Burgess IV