On 9/11/21 2:46 PM, Philippe Mathieu-Daudé wrote:
On 9/11/21 11:06 PM, Philippe Mathieu-Daudé wrote:
On 9/11/21 7:50 PM, Michael Tokarev wrote:
Hi.
The following warning is reported by the C compiler when compiling
tcg code on x32 architecture:
In file included from ../../tcg/tcg.c:429:
tcg/i386/tcg-target.c.inc: In function ‘tcg_out_movi_int’:
tcg/i386/tcg-target.c.inc:959:30: warning: cast to pointer from integer
of different size [-Wint-to-pointer-cast]
959 | diff = tcg_pcrel_diff(s, (const void *)arg) - 7;
Likely fixed by:
---
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index 98d924b91a8..0895f5670a1 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -956,7 +956,7 @@ static void tcg_out_movi_int(TCGContext *s, TCGType
type,
}
/* Try a 7 byte pc-relative lea before the 10 byte movq. */
- diff = tcg_pcrel_diff(s, (const void *)arg) - 7;
+ diff = tcg_pcrel_diff(s, (const void *)(uintptr_t)arg) - 7;
Hmm not quite. At this point tcg_out_movi_int() already checked 'arg'
does not fit into a 32-bit value... And on x32 we have sizeof(void*) = 4
so we can't cast a >32-bit value that way.
But tcg_out_movi_int() is called by tcg_out_movi(), and all 'arg' values
are either 0, 1 or a host address (often casted as uintptr_t).
That's false -- 'arg' is an arbitrary 64-bit constant here, for x32. But you're right that
no x32 pointers will arrive here, because TCG_TYPE_PTR == TCG_TYPE_I32 for that case and
we'll use the 5-byte mov immediate insn.
+ assert(sizeof(uintptr_t) > sizeof(uint32_t));
+
/* Try a 7 byte pc-relative lea before the 10 byte movq. */
diff = tcg_pcrel_diff(s, (const void *)arg) - 7;
if (diff == (int32_t)diff) {
We may need something like
if (sizeof(void *) == 8) {
diff = tcg_pcrel_diff(s, (const void *)(uintptr_t)arg) - 7;
...
}
I wonder if I still have an x32 vmm hanging about.
r~
