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digitalmars.D.learn - How to force an array literal into a read-only data segment?

reply Max Samukha <maxsamukha gmail.com> writes:
test.d:
__gshared t = "text".ptr;


As expected, the "text" literal ends up in a read-only data 
segment, with a pointer to it stored in a writable data segment 
(_TMP0 pointing into .rodata.str1.1):

.data   segment
_D4test1tPya:
         dd      offset FLAT:_TMP0 64
         db      000h,000h,000h,000h     ;....
.data   ends

Hex dump of section '.rodata.str1.1':
   0x00000000 74657874 00                         text.



How to achieve the same for an array literal? The closest I could 
come:

enum immutable(int[3]) _tmp = [1, 2, 3];
__gshared a = _tmp.ptr;

But the array is still placed into the writable segment:

.data   segment
internal:
         db      001h,000h,000h,000h,002h,000h,000h,000h ;........
         db      003h,000h,000h,000h,000h,000h,000h,000h ;........
_D4test1aPyi:
         dd      offset FLAT:internal 64
         db      000h,000h,000h,000h     ;....
.data   ends


Is it possible to force the array into rodata?
Sep 12 2019
parent reply a11e99z <black80 bk.ru> writes:
On Thursday, 12 September 2019 at 07:04:19 UTC, Max Samukha wrote:

 How to achieve the same for an array literal? The closest I 
 could come:

 enum immutable(int[3]) _tmp = [1, 2, 3];
 __gshared a = _tmp.ptr;

 Is it possible to force the array into rodata?


https://p0nce.github.io/d-idioms/#Precomputed-tables-at-compile-time-through-CTFE

static immutable(int[3]) _tmp = [1, 2, 3];
?
Sep 12 2019
parent Max Samukha <maxsamukha gmail.com> writes:
On Thursday, 12 September 2019 at 08:54:09 UTC, a11e99z wrote:

 On Thursday, 12 September 2019 at 07:04:19 UTC, Max Samukha 
 wrote:

 How to achieve the same for an array literal? The closest I 
 could come:

 enum immutable(int[3]) _tmp = [1, 2, 3];
 __gshared a = _tmp.ptr;

 Is it possible to force the array into rodata?


 https://p0nce.github.io/d-idioms/#Precomputed-tables-at-compile-time-through-CTFE

 static immutable(int[3]) _tmp = [1, 2, 3];
 ?


That looks the same as my example, where 'static' is redundant at 
the module level, and enum just removes the unneeded reference to 
the temporary from the object file. However, __gshared in my 
example does seem to be redundant - 'immutable' implies 
thread-shared in this case.
Sep 12 2019