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* [gcc/devel/omp/gcc-11] amdgcn: Fix DWARF variables with alloca
@ 2021-05-13 16:18 Kwok Yeung
0 siblings, 0 replies; only message in thread
From: Kwok Yeung @ 2021-05-13 16:18 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2e1eeae22bcbec6e17275417d7b8bc97300b7cb0
commit 2e1eeae22bcbec6e17275417d7b8bc97300b7cb0
Author: Andrew Stubbs <ams@codesourcery.com>
Date: Fri Jan 8 13:56:52 2021 +0000
amdgcn: Fix DWARF variables with alloca
Require a frame pointer for entry functions that use alloca because it isn't
possible to encode the DWARF frame otherwise. Adjust the CFA definition
expressions accordingly.
gcc/ChangeLog:
* config/gcn/gcn.c (gcn_expand_prologue): Use the frame pointer for
the DWARF CFA, if it exists.
(gcn_frame_pointer_rqd): Require a frame pointer for entry functions
that use alloca.
Diff:
---
gcc/config/gcn/gcn.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/gcc/config/gcn/gcn.c b/gcc/config/gcn/gcn.c
index c1823e8747e..784bae43419 100644
--- a/gcc/config/gcn/gcn.c
+++ b/gcc/config/gcn/gcn.c
@@ -3033,6 +3033,16 @@ gcn_expand_prologue ()
gen_rtx_SET (sp, gen_rtx_PLUS (DImode, sp,
dbg_adjustment)));
+ if (offsets->need_frame_pointer)
+ {
+ /* Set the CFA to the entry stack address, as an offset from the
+ frame pointer. This is necessary when alloca is used, and
+ harmless otherwise. */
+ rtx neg_adjust = gen_int_mode (-offsets->callee_saves, DImode);
+ add_reg_note (insn, REG_CFA_DEF_CFA,
+ gen_rtx_PLUS (DImode, fp, neg_adjust));
+ }
+
/* Make sure the flat scratch reg doesn't get optimised away. */
emit_insn (gen_prologue_use (gen_rtx_REG (DImode, FLAT_SCRATCH_REG)));
}
@@ -3144,10 +3154,13 @@ bool
gcn_frame_pointer_rqd (void)
{
/* GDB needs the frame pointer in order to unwind properly,
- but that's not important for the entry point.
- We should also repect the -fomit-frame-pointer flag. */
- return (cfun && cfun->machine && cfun->machine->normal_function
- && !flag_omit_frame_pointer);
+ but that's not important for the entry point, unless alloca is used.
+ It's not important for code execution, so we should repect the
+ -fomit-frame-pointer flag. */
+ return (!flag_omit_frame_pointer
+ && cfun
+ && (cfun->calls_alloca
+ || (cfun->machine && cfun->machine->normal_function)));
}
/* Implement TARGET_CAN_ELIMINATE.
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