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arm: Fix multiple inheritance thunks for thumb-1 with -mpure-code

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When -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:
g++.dg/ipa/pr46287-3.C
g++.dg/ipa/pr46984.C
g++.dg/opt/thunk1.C
g++.dg/torture/pr46287.C
g++.dg/torture/pr45699.C

2020-11-02  Christophe Lyon  <christophe.lyon@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.
This commit is contained in:
Christophe Lyon 2020-11-02 14:40:10 +00:00
parent c7f49e0579
commit 637aeb6b8d
1 changed files with 43 additions and 26 deletions
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69
gcc/config/arm/arm.c
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@ -28528,9 +28528,19 @@ 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 MI_DELTA from the
constant pool: we build it explicitly. */
if (target_pure_code)
{
thumb1_const_print r3 (file, 3);
thumb1_gen_const_int_1 (r3, mi_delta);
}
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);
}
@ -28566,30 +28576,37 @@ 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)
{
/* 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);
/* 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)
{
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);
}
}
else
{