From: Richard Sandiford <richard.sandiford@arm.com>
To: gcc-patches@gcc.gnu.org
Cc: Richard Sandiford <richard.sandiford@arm.com>
Subject: [PATCH 16/19] aarch64: Simplify probe of final frame allocation
Date: Tue, 12 Sep 2023 16:25:26 +0100 [thread overview]
Message-ID: <20230912152529.3322336-17-richard.sandiford@arm.com> (raw)
In-Reply-To: <20230912152529.3322336-1-richard.sandiford@arm.com>
Previous patches ensured that the final frame allocation only needs
a probe when the size is strictly greater than 1KiB. It's therefore
safe to use the normal 1024 probe offset in all cases.
The main motivation for doing this is to simplify the code and
remove the number of special cases.
gcc/
* config/aarch64/aarch64.cc (aarch64_allocate_and_probe_stack_space):
Always probe the residual allocation at offset 1024, asserting
that that is in range.
gcc/testsuite/
* gcc.target/aarch64/stack-check-prologue-17.c: Expect the probe
to be at offset 1024 rather than offset 0.
* gcc.target/aarch64/stack-check-prologue-18.c: Likewise.
* gcc.target/aarch64/stack-check-prologue-19.c: Likewise.
---
gcc/config/aarch64/aarch64.cc | 12 ++++--------
.../gcc.target/aarch64/stack-check-prologue-17.c | 2 +-
.../gcc.target/aarch64/stack-check-prologue-18.c | 4 ++--
.../gcc.target/aarch64/stack-check-prologue-19.c | 4 ++--
4 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 383b32f2078..bcb879ba94b 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -9887,16 +9887,12 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx temp2,
are still safe. */
if (residual)
{
- HOST_WIDE_INT residual_probe_offset = guard_used_by_caller;
+ gcc_assert (guard_used_by_caller + byte_sp_alignment <= size);
+
/* If we're doing final adjustments, and we've done any full page
allocations then any residual needs to be probed. */
if (final_adjustment_p && rounded_size != 0)
min_probe_threshold = 0;
- /* If doing a small final adjustment, we always probe at offset 0.
- This is done to avoid issues when the final adjustment is smaller
- than the probing offset. */
- else if (final_adjustment_p && rounded_size == 0)
- residual_probe_offset = 0;
aarch64_sub_sp (temp1, temp2, residual, frame_related_p);
if (residual >= min_probe_threshold)
@@ -9907,8 +9903,8 @@ aarch64_allocate_and_probe_stack_space (rtx temp1, rtx temp2,
HOST_WIDE_INT_PRINT_DEC " bytes, probing will be required."
"\n", residual);
- emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
- residual_probe_offset));
+ emit_stack_probe (plus_constant (Pmode, stack_pointer_rtx,
+ guard_used_by_caller));
emit_insn (gen_blockage ());
}
}
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
index 0d8a25d73a2..f0ec1389771 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-17.c
@@ -33,7 +33,7 @@ int test1(int z) {
** ...
** str x30, \[sp\]
** sub sp, sp, #1040
-** str xzr, \[sp\]
+** str xzr, \[sp, #?1024\]
** cbnz w0, .*
** bl g
** ...
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
index 82447d20fff..6383bec5ebc 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-18.c
@@ -9,7 +9,7 @@ void g();
** ...
** str x30, \[sp\]
** sub sp, sp, #4064
-** str xzr, \[sp\]
+** str xzr, \[sp, #?1024\]
** cbnz w0, .*
** bl g
** ...
@@ -50,7 +50,7 @@ int test1(int z) {
** ...
** str x30, \[sp\]
** sub sp, sp, #1040
-** str xzr, \[sp\]
+** str xzr, \[sp, #?1024\]
** cbnz w0, .*
** bl g
** ...
diff --git a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
index 73ac3e4e4eb..562039b5e9b 100644
--- a/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
+++ b/gcc/testsuite/gcc.target/aarch64/stack-check-prologue-19.c
@@ -9,7 +9,7 @@ void g();
** ...
** str x30, \[sp\]
** sub sp, sp, #4064
-** str xzr, \[sp\]
+** str xzr, \[sp, #?1024\]
** cbnz w0, .*
** bl g
** ...
@@ -50,7 +50,7 @@ int test1(int z) {
** ...
** str x30, \[sp\]
** sub sp, sp, #1040
-** str xzr, \[sp\]
+** str xzr, \[sp, #?1024\]
** cbnz w0, .*
** bl g
** ...
--
2.25.1
next prev parent reply other threads:[~2023-09-12 15:25 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 15:25 [PATCH 00/19] aarch64: Fix -fstack-protector issue Richard Sandiford
2023-09-12 15:25 ` [PATCH 01/19] aarch64: Use local frame vars in shrink-wrapping code Richard Sandiford
2023-09-12 15:25 ` [PATCH 02/19] aarch64: Avoid a use of callee_offset Richard Sandiford
2023-09-12 15:25 ` [PATCH 03/19] aarch64: Explicitly handle frames with no saved registers Richard Sandiford
2023-09-12 15:25 ` [PATCH 04/19] aarch64: Add bytes_below_saved_regs to frame info Richard Sandiford
2023-09-12 15:25 ` [PATCH 05/19] aarch64: Add bytes_below_hard_fp " Richard Sandiford
2023-09-12 15:25 ` [PATCH 06/19] aarch64: Tweak aarch64_save/restore_callee_saves Richard Sandiford
2023-09-12 15:25 ` [PATCH 07/19] aarch64: Only calculate chain_offset if there is a chain Richard Sandiford
2023-09-12 15:25 ` [PATCH 08/19] aarch64: Rename locals_offset to bytes_above_locals Richard Sandiford
2023-09-12 15:25 ` [PATCH 09/19] aarch64: Rename hard_fp_offset to bytes_above_hard_fp Richard Sandiford
2023-09-12 15:25 ` [PATCH 10/19] aarch64: Tweak frame_size comment Richard Sandiford
2023-09-12 15:25 ` [PATCH 11/19] aarch64: Measure reg_offset from the bottom of the frame Richard Sandiford
2023-09-12 15:25 ` [PATCH 12/19] aarch64: Simplify top of frame allocation Richard Sandiford
2023-09-12 15:25 ` [PATCH 13/19] aarch64: Minor initial adjustment tweak Richard Sandiford
2023-09-12 15:25 ` [PATCH 14/19] aarch64: Tweak stack clash boundary condition Richard Sandiford
2023-09-12 15:25 ` [PATCH 15/19] aarch64: Put LR save probe in first 16 bytes Richard Sandiford
2023-09-12 15:25 ` Richard Sandiford [this message]
2023-09-12 15:25 ` [PATCH 17/19] aarch64: Explicitly record probe registers in frame info Richard Sandiford
2023-09-12 15:25 ` [PATCH 18/19] aarch64: Remove below_hard_fp_saved_regs_size Richard Sandiford
2023-09-12 15:25 ` [PATCH 19/19] aarch64: Make stack smash canary protect saved registers Richard Sandiford
2023-09-12 16:45 ` [PATCH 00/19] aarch64: Fix -fstack-protector issue Siddhesh Poyarekar
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