* [PATCH][AArch64] Introduce emit_frame_chain
@ 2017-08-04 12:26 Wilco Dijkstra
2017-08-15 16:27 ` Wilco Dijkstra
2017-10-26 16:23 ` James Greenhalgh
0 siblings, 2 replies; 3+ messages in thread
From: Wilco Dijkstra @ 2017-08-04 12:26 UTC (permalink / raw)
To: GCC Patches, James Greenhalgh; +Cc: nd
The current frame code combines the separate concepts of a frame chain
(saving old FP,LR in a record and pointing new FP to it) and a frame
pointer used to access locals. Add emit_frame_chain to the aarch64_frame
descriptor and use it in the prolog and epilog code. For now just
initialize it as before, so generated code is identical.
Also correctly set EXIT_IGNORE_STACK. The current AArch64 epilog code
restores SP from FP if alloca is used. If a frame pointer is used but
there is no alloca, SP must remain valid for the epilog to work correctly.
ChangeLog:
2017-08-03 Wilco Dijkstra <wdijkstr@arm.com>
gcc/
* config/aarch64/aarch64.h (EXIT_IGNORE_STACK): Set if alloca is used.
(aarch64_frame): Add emit_frame_chain boolean.
* config/aarch64/aarch64.c (aarch64_frame_pointer_required)
Move eh_return case to aarch64_layout_frame.
(aarch64_layout_frame): Initialize emit_frame_chain.
(aarch64_expand_prologue): Use emit_frame_chain.
--
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 82d270e575ca40e9786de6a4e27408a32bc09be7..ee23944b191dd17339f42ce8ea7ff9733357c3d8 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -346,9 +346,9 @@ extern unsigned aarch64_architecture_version;
(epilogue_completed && (REGNO) == LR_REGNUM)
/* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
- the stack pointer does not matter. The value is tested only in
- functions that have frame pointers. */
-#define EXIT_IGNORE_STACK 1
+ the stack pointer does not matter. This is only true if the function
+ uses alloca. */
+#define EXIT_IGNORE_STACK (cfun->calls_alloca)
#define STATIC_CHAIN_REGNUM R18_REGNUM
#define HARD_FRAME_POINTER_REGNUM R29_REGNUM
@@ -604,6 +604,9 @@ struct GTY (()) aarch64_frame
/* The size of the stack adjustment after saving callee-saves. */
HOST_WIDE_INT final_adjust;
+ /* Store FP,LR and setup a frame pointer. */
+ bool emit_frame_chain;
+
unsigned wb_candidate1;
unsigned wb_candidate2;
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index e5c6c1ca65269a209e893729ce3230f70bd4e808..0c355506e2a1605d24d1e89934a063e5f333eebf 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -2847,10 +2847,6 @@ aarch64_frame_pointer_required (void)
&& (!crtl->is_leaf || df_regs_ever_live_p (LR_REGNUM)))
return true;
- /* Force a frame pointer for EH returns so the return address is at FP+8. */
- if (crtl->calls_eh_return)
- return true;
-
return false;
}
@@ -2866,6 +2862,10 @@ aarch64_layout_frame (void)
if (reload_completed && cfun->machine->frame.laid_out)
return;
+ /* Force a frame chain for EH returns so the return address is at FP+8. */
+ cfun->machine->frame.emit_frame_chain
+ = frame_pointer_needed || crtl->calls_eh_return;
+
#define SLOT_NOT_REQUIRED (-2)
#define SLOT_REQUIRED (-1)
@@ -2900,7 +2900,7 @@ aarch64_layout_frame (void)
last_fp_reg = regno;
}
- if (frame_pointer_needed)
+ if (cfun->machine->frame.emit_frame_chain)
{
/* FP and LR are placed in the linkage record. */
cfun->machine->frame.reg_offset[R29_REGNUM] = 0;
@@ -3639,6 +3639,7 @@ aarch64_expand_prologue (void)
HOST_WIDE_INT callee_offset = cfun->machine->frame.callee_offset;
unsigned reg1 = cfun->machine->frame.wb_candidate1;
unsigned reg2 = cfun->machine->frame.wb_candidate2;
+ bool emit_frame_chain = cfun->machine->frame.emit_frame_chain;
rtx_insn *insn;
/* Sign return address for functions. */
@@ -3669,7 +3670,7 @@ aarch64_expand_prologue (void)
if (callee_adjust != 0)
aarch64_push_regs (reg1, reg2, callee_adjust);
- if (frame_pointer_needed)
+ if (emit_frame_chain)
{
if (callee_adjust == 0)
aarch64_save_callee_saves (DImode, callee_offset, R29_REGNUM,
@@ -3677,12 +3678,12 @@ aarch64_expand_prologue (void)
insn = emit_insn (gen_add3_insn (hard_frame_pointer_rtx,
stack_pointer_rtx,
GEN_INT (callee_offset)));
- RTX_FRAME_RELATED_P (insn) = 1;
+ RTX_FRAME_RELATED_P (insn) = frame_pointer_needed;
emit_insn (gen_stack_tie (stack_pointer_rtx, hard_frame_pointer_rtx));
}
aarch64_save_callee_saves (DImode, callee_offset, R0_REGNUM, R30_REGNUM,
- callee_adjust != 0 || frame_pointer_needed);
+ callee_adjust != 0 || emit_frame_chain);
aarch64_save_callee_saves (DFmode, callee_offset, V0_REGNUM, V31_REGNUM,
callee_adjust != 0 || frame_pointer_needed);
aarch64_sub_sp (IP1_REGNUM, final_adjust, !frame_pointer_needed);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][AArch64] Introduce emit_frame_chain
2017-08-04 12:26 [PATCH][AArch64] Introduce emit_frame_chain Wilco Dijkstra
@ 2017-08-15 16:27 ` Wilco Dijkstra
2017-10-26 16:23 ` James Greenhalgh
1 sibling, 0 replies; 3+ messages in thread
From: Wilco Dijkstra @ 2017-08-15 16:27 UTC (permalink / raw)
To: GCC Patches, James Greenhalgh; +Cc: nd
ping
From: Wilco Dijkstra
Sent: 04 August 2017 13:26
To: GCC Patches; James Greenhalgh
Cc: nd
Subject: [PATCH][AArch64] Introduce emit_frame_chain
The current frame code combines the separate concepts of a frame chain
(saving old FP,LR in a record and pointing new FP to it) and a frame
pointer used to access locals. Add emit_frame_chain to the aarch64_frame
descriptor and use it in the prolog and epilog code. For now just
initialize it as before, so generated code is identical.
Also correctly set EXIT_IGNORE_STACK. The current AArch64 epilog code
restores SP from FP if alloca is used. If a frame pointer is used but
there is no alloca, SP must remain valid for the epilog to work correctly.
ChangeLog:
2017-08-03 Wilco Dijkstra <wdijkstr@arm.com>
gcc/
* config/aarch64/aarch64.h (EXIT_IGNORE_STACK): Set if alloca is used.
(aarch64_frame): Add emit_frame_chain boolean.
* config/aarch64/aarch64.c (aarch64_frame_pointer_required)
Move eh_return case to aarch64_layout_frame.
(aarch64_layout_frame): Initialize emit_frame_chain.
(aarch64_expand_prologue): Use emit_frame_chain.
--
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 82d270e575ca40e9786de6a4e27408a32bc09be7..ee23944b191dd17339f42ce8ea7ff9733357c3d8 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -346,9 +346,9 @@ extern unsigned aarch64_architecture_version;
(epilogue_completed && (REGNO) == LR_REGNUM)
/* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
- the stack pointer does not matter. The value is tested only in
- functions that have frame pointers. */
-#define EXIT_IGNORE_STACK 1
+ the stack pointer does not matter. This is only true if the function
+ uses alloca. */
+#define EXIT_IGNORE_STACK (cfun->calls_alloca)
#define STATIC_CHAIN_REGNUM R18_REGNUM
#define HARD_FRAME_POINTER_REGNUM R29_REGNUM
@@ -604,6 +604,9 @@ struct GTY (()) aarch64_frame
/* The size of the stack adjustment after saving callee-saves. */
HOST_WIDE_INT final_adjust;
+ /* Store FP,LR and setup a frame pointer. */
+ bool emit_frame_chain;
+
unsigned wb_candidate1;
unsigned wb_candidate2;
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index e5c6c1ca65269a209e893729ce3230f70bd4e808..0c355506e2a1605d24d1e89934a063e5f333eebf 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -2847,10 +2847,6 @@ aarch64_frame_pointer_required (void)
&& (!crtl->is_leaf || df_regs_ever_live_p (LR_REGNUM)))
return true;
- /* Force a frame pointer for EH returns so the return address is at FP+8. */
- if (crtl->calls_eh_return)
- return true;
-
return false;
}
@@ -2866,6 +2862,10 @@ aarch64_layout_frame (void)
if (reload_completed && cfun->machine->frame.laid_out)
return;
+ /* Force a frame chain for EH returns so the return address is at FP+8. */
+ cfun->machine->frame.emit_frame_chain
+ = frame_pointer_needed || crtl->calls_eh_return;
+
#define SLOT_NOT_REQUIRED (-2)
#define SLOT_REQUIRED (-1)
@@ -2900,7 +2900,7 @@ aarch64_layout_frame (void)
last_fp_reg = regno;
}
- if (frame_pointer_needed)
+ if (cfun->machine->frame.emit_frame_chain)
{
/* FP and LR are placed in the linkage record. */
cfun->machine->frame.reg_offset[R29_REGNUM] = 0;
@@ -3639,6 +3639,7 @@ aarch64_expand_prologue (void)
HOST_WIDE_INT callee_offset = cfun->machine->frame.callee_offset;
unsigned reg1 = cfun->machine->frame.wb_candidate1;
unsigned reg2 = cfun->machine->frame.wb_candidate2;
+ bool emit_frame_chain = cfun->machine->frame.emit_frame_chain;
rtx_insn *insn;
/* Sign return address for functions. */
@@ -3669,7 +3670,7 @@ aarch64_expand_prologue (void)
if (callee_adjust != 0)
aarch64_push_regs (reg1, reg2, callee_adjust);
- if (frame_pointer_needed)
+ if (emit_frame_chain)
{
if (callee_adjust == 0)
aarch64_save_callee_saves (DImode, callee_offset, R29_REGNUM,
@@ -3677,12 +3678,12 @@ aarch64_expand_prologue (void)
insn = emit_insn (gen_add3_insn (hard_frame_pointer_rtx,
stack_pointer_rtx,
GEN_INT (callee_offset)));
- RTX_FRAME_RELATED_P (insn) = 1;
+ RTX_FRAME_RELATED_P (insn) = frame_pointer_needed;
emit_insn (gen_stack_tie (stack_pointer_rtx, hard_frame_pointer_rtx));
}
aarch64_save_callee_saves (DImode, callee_offset, R0_REGNUM, R30_REGNUM,
- callee_adjust != 0 || frame_pointer_needed);
+ callee_adjust != 0 || emit_frame_chain);
aarch64_save_callee_saves (DFmode, callee_offset, V0_REGNUM, V31_REGNUM,
callee_adjust != 0 || frame_pointer_needed);
aarch64_sub_sp (IP1_REGNUM, final_adjust, !frame_pointer_needed);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH][AArch64] Introduce emit_frame_chain
2017-08-04 12:26 [PATCH][AArch64] Introduce emit_frame_chain Wilco Dijkstra
2017-08-15 16:27 ` Wilco Dijkstra
@ 2017-10-26 16:23 ` James Greenhalgh
1 sibling, 0 replies; 3+ messages in thread
From: James Greenhalgh @ 2017-10-26 16:23 UTC (permalink / raw)
To: Wilco Dijkstra; +Cc: GCC Patches, nd
On Fri, Aug 04, 2017 at 01:26:15PM +0100, Wilco Dijkstra wrote:
> The current frame code combines the separate concepts of a frame chain
> (saving old FP,LR in a record and pointing new FP to it) and a frame
> pointer used to access locals. Add emit_frame_chain to the aarch64_frame
> descriptor and use it in the prolog and epilog code. For now just
> initialize it as before, so generated code is identical.
>
> Also correctly set EXIT_IGNORE_STACK. The current AArch64 epilog code
> restores SP from FP if alloca is used. If a frame pointer is used but
> there is no alloca, SP must remain valid for the epilog to work correctly.
OK.
Reviewed by: James Greenhalgh <james.greenhalgh@arm.com>
Thanks,
James
>
> ChangeLog:
> 2017-08-03 Wilco Dijkstra <wdijkstr@arm.com>
>
> gcc/
> * config/aarch64/aarch64.h (EXIT_IGNORE_STACK): Set if alloca is used.
> (aarch64_frame): Add emit_frame_chain boolean.
> * config/aarch64/aarch64.c (aarch64_frame_pointer_required)
> Move eh_return case to aarch64_layout_frame.
> (aarch64_layout_frame): Initialize emit_frame_chain.
> (aarch64_expand_prologue): Use emit_frame_chain.
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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