Re: How to force an array literal into a read-only data segment?

[Max Samukha via Digitalmars-d-learn]

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.

Re: How to force an array literal into a read-only data segment?

[a11e99z via Digitalmars-d-learn]

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];
?

How to force an array literal into a read-only data segment?

[Max Samukha via Digitalmars-d-learn]

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':
  0x 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?