[compiler-rt] r246454 - builtins: implement __emutls_get_address
H.J. Lu via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 4 08:36:39 PDT 2015
On Fri, Sep 4, 2015 at 8:30 AM, H.J. Lu <hjl.tools at gmail.com> wrote:
> On Fri, Sep 4, 2015 at 8:15 AM, Joerg Sonnenberger via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> On Fri, Sep 04, 2015 at 08:00:34AM -0700, H.J. Lu via llvm-commits wrote:
>>> > +/* Emulated TLS objects are always allocated at run-time. */
>>> > +static inline void* emutls_allocate_object(__emutls_control* control) {
>>> > + /* Use standard C types, check with gcc's emutls.o. */
>>> > + typedef unsigned int gcc_word __attribute__((mode(word)));
>>> > + typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
>>> > + COMPILE_TIME_ASSERT(sizeof(size_t) == sizeof(gcc_word));
>>>
>>> What is this assert for? It is false for x32 where size_t is 4 bytes and
>>> gcc_word 8 bytes.
>>
>> To ensure that the struct layout is ABI compatible. So what layout does
>> GCC use?
>>
>
> Why not use
>
> typedef unsigned int gcc_word __attribute__((mode(word)));
> typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
> typedef struct __emutls_control {
> gcc_word size; /* size of the object in bytes */
> gcc_word align; /* alignment of the object in bytes */
> union {
> gcc_pointer index; /* data[index-1] is the object address */
> void* address; /* object address, when in single thread env */
> } object;
> void* value; /* null or non-zero initial value for the object */
> } __emutls_control;
>
> then?
>
Something like this.
--
H.J.
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