Comment #0 by bearophile_hugs — 2011-05-03T03:04:41Z
I am not sure about the errors shown here (so no keywords). Please close this bug report if things here are working as expected.
D2 code:
void main() {
immutable size_t x = 10;
asm {
mov EDI, x;
}
}
DMD 2.052 shows the error:
test.d(2): Error: Integer constant expression expected instead of x = 10u
--------------------------
D2 code, static (thread-local) variables can't be used in ASM:
void main() {
static size_t x = 10;
asm {
mov EDI, x;
}
}
It produces:
object.Error: Access Violation
They work using __gshared, this gives no errors:
void main() {
__gshared static size_t x = 10;
asm {
mov EDI, x;
}
}
My suggestion is to remove this source of errors. One solution may be to disallow the direct access to static variables from asm code, avoiding this bug.
Comment #1 by verylonglogin.reg — 2012-03-02T06:37:11Z
The first one is definetly a bug with const/immutable local variables:
---
void f() {
const size_t a = 1; // Error: Integer constant expression expected instead of a = 1u
version (D_InlineAsm_X86_64)
asm { mov RAX, a; }
else version (D_InlineAsm_X86)
asm { mov EAX, a; }
else
static assert(1);
}
---
The second one looks like expected behaviour because with current inline assembler for non-stack varable `someVar` instruction `mov EAX, someVar;` is equal to `mov EAX, [someVar];` and `mov EAX, [n];` where `n` is a displacement of `someVar` from some initial addres which depends on `someVar` type (global, shared, or TLS).
Inline assembler behaves in this way but I've never seen any documentation and reasons *why* does it behave this way because it's really unobvious.
Comment #2 by yebblies — 2013-01-16T05:04:57Z
For some reason x's initializer is "x = 10" instead of just "10". Probably a side effect of some hack.
Comment #3 by bugzilla — 2020-08-22T00:18:54Z
In reply to bearophile_hugs from comment #0)
> --------------------------
>
> D2 code, static (thread-local) variables can't be used in ASM:
>
> [...]
Moved to https://issues.dlang.org/show_bug.cgi?id=21186 as it is a different bug.