When mi_delta is > 255 and -mpure-code is used, we cannot load delta
from code memory (like we do without -mpure-code).
This patch builds the value of mi_delta into r3 with a series of
movs/adds/lsls.
We also do some cleanup by not emitting the function address and delta
via .word directives at the end of the thunk since we don't use them
with -mpure-code.
No need for new testcases, this bug was already identified by
eg. pr46287-3.C
2020-09-29 Christophe Lyon <christophe.l...@linaro.org>
gcc/
* config/arm/arm.c (arm_thumb1_mi_thunk): Build mi_delta in r3 and
do not emit function address and delta when -mpure-code is used.
k# (use "git pull" to merge the remote branch into yours)
---
gcc/config/arm/arm.c | 91 +++++++++++++++++++++++++++++++++++++---------------
1 file changed, 66 insertions(+), 25 deletions(-)
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index ceeb91f..62abeb5 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -28342,9 +28342,43 @@ arm_thumb1_mi_thunk (FILE *file, tree, HOST_WIDE_INT
delta,
{
if (mi_delta > 255)
{
- fputs ("\tldr\tr3, ", file);
- assemble_name (file, label);
- fputs ("+4\n", file);
+ /* With -mpure-code, we cannot load delta from the constant
+ pool: we build it explicitly. */
+ if (target_pure_code)
+ {
+ bool mov_done_p = false;
+ int i;
+
+ /* Emit upper 3 bytes if needed. */
+ for (i = 0; i < 3; i++)
+ {
+ int byte = (mi_delta >> (8 * (3 - i))) & 0xff;
+
+ if (byte)
+ {
+ if (mov_done_p)
+ asm_fprintf (file, "\tadds\tr3, #%d\n", byte);
+ else
+ asm_fprintf (file, "\tmovs\tr3, #%d\n", byte);
+ mov_done_p = true;
+ }
+
+ if (mov_done_p)
+ asm_fprintf (file, "\tlsls\tr3, #8\n");
+ }
+
+ /* Emit lower byte if needed. */
+ if (!mov_done_p)
+ asm_fprintf (file, "\tmovs\tr3, #%d\n", mi_delta & 0xff);
+ else if (mi_delta & 0xff)
+ asm_fprintf (file, "\tadds\tr3, #%d\n", mi_delta & 0xff);
+ }
+ else
+ {
+ fputs ("\tldr\tr3, ", file);
+ assemble_name (file, label);
+ fputs ("+4\n", file);
+ }
asm_fprintf (file, "\t%ss\t%r, %r, r3\n",
mi_op, this_regno, this_regno);
}
@@ -28380,30 +28414,37 @@ arm_thumb1_mi_thunk (FILE *file, tree, HOST_WIDE_INT
delta,
fputs ("\tpop\t{r3}\n", file);
fprintf (file, "\tbx\tr12\n");
- ASM_OUTPUT_ALIGN (file, 2);
- assemble_name (file, label);
- fputs (":\n", file);
- if (flag_pic)
+
+ /* With -mpure-code, we don't need to emit literals for the
+ function address and delta since we emitted code to build
+ them. */
+ if (!target_pure_code)
{
- /* Output ".word .LTHUNKn-[3,7]-.LTHUNKPCn". */
- rtx tem = XEXP (DECL_RTL (function), 0);
- /* For TARGET_THUMB1_ONLY the thunk is in Thumb mode, so the PC
- pipeline offset is four rather than eight. Adjust the offset
- accordingly. */
- tem = plus_constant (GET_MODE (tem), tem,
- TARGET_THUMB1_ONLY ? -3 : -7);
- tem = gen_rtx_MINUS (GET_MODE (tem),
- tem,
- gen_rtx_SYMBOL_REF (Pmode,
- ggc_strdup (labelpc)));
- assemble_integer (tem, 4, BITS_PER_WORD, 1);
- }
- else
- /* Output ".word .LTHUNKn". */
- assemble_integer (XEXP (DECL_RTL (function), 0), 4, BITS_PER_WORD, 1);
+ ASM_OUTPUT_ALIGN (file, 2);
+ assemble_name (file, label);
+ fputs (":\n", file);
+ if (flag_pic)
+ {
+ /* Output ".word .LTHUNKn-[3,7]-.LTHUNKPCn". */
+ rtx tem = XEXP (DECL_RTL (function), 0);
+ /* For TARGET_THUMB1_ONLY the thunk is in Thumb mode, so the PC
+ pipeline offset is four rather than eight. Adjust the offset
+ accordingly. */
+ tem = plus_constant (GET_MODE (tem), tem,
+ TARGET_THUMB1_ONLY ? -3 : -7);
+ tem = gen_rtx_MINUS (GET_MODE (tem),
+ tem,
+ gen_rtx_SYMBOL_REF (Pmode,
+ ggc_strdup (labelpc)));
+ assemble_integer (tem, 4, BITS_PER_WORD, 1);
+ }
+ else
+ /* Output ".word .LTHUNKn". */
+ assemble_integer (XEXP (DECL_RTL (function), 0), 4, BITS_PER_WORD,
1);
- if (TARGET_THUMB1_ONLY && mi_delta > 255)
- assemble_integer (GEN_INT(mi_delta), 4, BITS_PER_WORD, 1);
+ if (TARGET_THUMB1_ONLY && mi_delta > 255)
+ assemble_integer (GEN_INT(mi_delta), 4, BITS_PER_WORD, 1);
+ }
}
else
{
--
2.7.4
