[compiler-rt] r246454 - builtins: implement __emutls_get_address

[H.J. Lu via llvm-commits]

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.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Use-gcc_word-and-gcc_pointer-in-__emutls_control.patch
Type: text/x-patch
Size: 2659 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150904/f5f52f14/attachment.bin>