From cbf6da166ea7993e166dcb121fc7b9ef4ec87c89 Mon Sep 17 00:00:00 2001
From: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Sat, 5 Aug 2023 14:56:31 +0200
Subject: [PATCH] target: Support heap-based trampolines
Enable -ftrampoline-impl=heap by default if we are on macOS 11
or later.
Co-Authored-By: Maxim Blinov <maxim.blinov@embecosm.com>
Co-Authored-By: Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
Co-Authored-By: Iain Sandoe <iain@sandoe.co.uk>
gcc/ChangeLog:
* config.gcc: Default to heap trampolines on macOS 11 and above.
* config/i386/darwin.h: Define X86_CUSTOM_FUNCTION_TEST.
* config/i386/i386.h: Define X86_CUSTOM_FUNCTION_TEST.
* config/i386/i386.cc: Use X86_CUSTOM_FUNCTION_TEST.
---
gcc/config.gcc | 11 +++++++++++
gcc/config/i386/darwin.h | 6 ++++++
gcc/config/i386/i386.cc | 2 +-
gcc/config/i386/i386.h | 6 ++++++
4 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 0782cbc6e915..606d3a8513ea 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -1171,6 +1171,17 @@ case ${target} in
;;
esac
+# Figure out if we need to enable heap trampolines by default
+case ${target} in
+*-*-darwin2*)
+ # Currently, we do this for macOS 11 and above.
+ tm_defines="$tm_defines HEAP_TRAMPOLINES_INIT=1"
+ ;;
+*)
+ tm_defines="$tm_defines HEAP_TRAMPOLINES_INIT=0"
+ ;;
+esac
+
case ${target} in
aarch64*-*-elf | aarch64*-*-fuchsia* | aarch64*-*-rtems*)
tm_file="${tm_file} elfos.h newlib-stdint.h"
diff --git a/gcc/config/i386/darwin.h b/gcc/config/i386/darwin.h
index 588bd669bddc..036eefbbb95f 100644
--- a/gcc/config/i386/darwin.h
+++ b/gcc/config/i386/darwin.h
@@ -308,3 +308,9 @@ along with GCC; see the file COPYING3. If not see
#define CLEAR_INSN_CACHE(beg, end) \
extern void sys_icache_invalidate(void *start, size_t len); \
sys_icache_invalidate ((beg), (size_t)((end)-(beg)))
+
+/* Disable custom function descriptors for Darwin when we have off-stack
+ trampolines. */
+#undef X86_CUSTOM_FUNCTION_TEST
+#define X86_CUSTOM_FUNCTION_TEST \
+ (flag_trampolines && flag_trampoline_impl == TRAMPOLINE_IMPL_HEAP) ? 0 : 1
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 641e76803355..f4772e0cb698 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -26287,7 +26287,7 @@ ix86_libgcc_floating_mode_supported_p
#define TARGET_HARD_REGNO_SCRATCH_OK ix86_hard_regno_scratch_ok
#undef TARGET_CUSTOM_FUNCTION_DESCRIPTORS
-#define TARGET_CUSTOM_FUNCTION_DESCRIPTORS 1
+#define TARGET_CUSTOM_FUNCTION_DESCRIPTORS X86_CUSTOM_FUNCTION_TEST
#undef TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID
#define TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID ix86_addr_space_zero_address_valid
diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 4dd26e35a3e8..7e66fa095855 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -760,6 +760,12 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
/* Minimum allocation boundary for the code of a function. */
#define FUNCTION_BOUNDARY 8
+/* We will and with this value to test if a custom function descriptor needs
+ a static chain. The function boundary must the adjusted so that the bit
+ this represents is no longer part of the address. 0 Disables the custom
+ function descriptors. */
+#define X86_CUSTOM_FUNCTION_TEST 1
+
/* C++ stores the virtual bit in the lowest bit of function pointers. */
#define TARGET_PTRMEMFUNC_VBIT_LOCATION ptrmemfunc_vbit_in_pfn
--
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