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clang-p2996/compiler-rt/lib/builtins/assembly.h
Victor Campos a59a8ae1a9 [compiler-rt][ARM] Add missing PACBTI support to assembly aeabi functions (#142400) 
Some of the aeabi functions were missing PACBTI support. The lack of it
resulted in exceptions at runtime if the running environment had PAC
and/or BTI enabled.

This patch adds this support. This involves the addition of PACBTI
instructions, depending on whether each of these features is enabled,
plus the saving and restoring of the PAC code that resides in r12. Some
of the common code has been put in preprocessor macros to reduce
duplication, but not all, especially since some register saving and
restoring is very specific to each context.
2025-06-10 10:20:42 +01:00

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//===-- assembly.h - compiler-rt assembler support macros -----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines macros for use in compiler-rt assembler source.
// This file is not part of the interface of this library.
//
//===----------------------------------------------------------------------===//
#ifndef COMPILERRT_ASSEMBLY_H
#define COMPILERRT_ASSEMBLY_H
#if defined(__linux__) && defined(__CET__)
#if __has_include(<cet.h>)
#include <cet.h>
#endif
#endif
#if defined(__APPLE__) && defined(__aarch64__)
#define SEPARATOR %%
#else
#define SEPARATOR ;
#endif
#if defined(__APPLE__)
#define HIDDEN(name) .private_extern name
#define LOCAL_LABEL(name) L_##name
// tell linker it can break up file at label boundaries
#define FILE_LEVEL_DIRECTIVE .subsections_via_symbols
#define SYMBOL_IS_FUNC(name)
#define CONST_SECTION .const
#define NO_EXEC_STACK_DIRECTIVE
#elif defined(__ELF__)
#define HIDDEN(name) .hidden name
#define LOCAL_LABEL(name) .L_##name
#define FILE_LEVEL_DIRECTIVE
#if defined(__arm__) || defined(__aarch64__)
#define SYMBOL_IS_FUNC(name) .type name,%function
#else
#define SYMBOL_IS_FUNC(name) .type name,@function
#endif
#define CONST_SECTION .section .rodata
#if defined(__GNU__) || defined(__FreeBSD__) || defined(__Fuchsia__) || \
defined(__linux__)
#define NO_EXEC_STACK_DIRECTIVE .section .note.GNU-stack,"",%progbits
#else
#define NO_EXEC_STACK_DIRECTIVE
#endif
#else // !__APPLE__ && !__ELF__
#define HIDDEN(name)
#define LOCAL_LABEL(name) .L ## name
#define FILE_LEVEL_DIRECTIVE
#define SYMBOL_IS_FUNC(name) \
.def FUNC_SYMBOL(name) SEPARATOR \
.scl 2 SEPARATOR \
.type 32 SEPARATOR \
.endef
#define CONST_SECTION .section .rdata,"rd"
#define NO_EXEC_STACK_DIRECTIVE
#endif
#if defined(__arm__) || defined(__aarch64__) || defined(__arm64ec__)
#define FUNC_ALIGN \
.text SEPARATOR \
.balign 16 SEPARATOR
#else
#define FUNC_ALIGN
#endif
// BTI and PAC gnu property note
#define NT_GNU_PROPERTY_TYPE_0 5
#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000
#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI 1
#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC 2
#if defined(__ARM_FEATURE_BTI_DEFAULT)
#define BTI_FLAG GNU_PROPERTY_AARCH64_FEATURE_1_BTI
#else
#define BTI_FLAG 0
#endif
#if __ARM_FEATURE_PAC_DEFAULT & 3
#define PAC_FLAG GNU_PROPERTY_AARCH64_FEATURE_1_PAC
#else
#define PAC_FLAG 0
#endif
#define GNU_PROPERTY(type, value) \
.pushsection .note.gnu.property, "a" SEPARATOR \
.p2align 3 SEPARATOR \
.word 4 SEPARATOR \
.word 16 SEPARATOR \
.word NT_GNU_PROPERTY_TYPE_0 SEPARATOR \
.asciz "GNU" SEPARATOR \
.word type SEPARATOR \
.word 4 SEPARATOR \
.word value SEPARATOR \
.word 0 SEPARATOR \
.popsection
#if BTI_FLAG != 0
#define BTI_C hint #34
#define BTI_J hint #36
#else
#define BTI_C
#define BTI_J
#endif
#if (BTI_FLAG | PAC_FLAG) != 0
#define GNU_PROPERTY_BTI_PAC \
GNU_PROPERTY(GNU_PROPERTY_AARCH64_FEATURE_1_AND, BTI_FLAG | PAC_FLAG)
#else
#define GNU_PROPERTY_BTI_PAC
#endif
#if defined(__clang__) || defined(__GCC_HAVE_DWARF2_CFI_ASM)
#define CFI_START .cfi_startproc
#define CFI_END .cfi_endproc
#else
#define CFI_START
#define CFI_END
#endif
#if defined(__arm__)
// Determine actual [ARM][THUMB[1][2]] ISA using compiler predefined macros:
// - for '-mthumb -march=armv6' compiler defines '__thumb__'
// - for '-mthumb -march=armv7' compiler defines '__thumb__' and '__thumb2__'
#if defined(__thumb2__) || defined(__thumb__)
#define DEFINE_CODE_STATE .thumb SEPARATOR
#define DECLARE_FUNC_ENCODING .thumb_func SEPARATOR
#if defined(__thumb2__)
#define USE_THUMB_2
#define IT(cond) it cond
#define ITT(cond) itt cond
#define ITE(cond) ite cond
#else
#define USE_THUMB_1
#define IT(cond)
#define ITT(cond)
#define ITE(cond)
#endif // defined(__thumb__2)
#else // !defined(__thumb2__) && !defined(__thumb__)
#define DEFINE_CODE_STATE .arm SEPARATOR
#define DECLARE_FUNC_ENCODING
#define IT(cond)
#define ITT(cond)
#define ITE(cond)
#endif
#if defined(USE_THUMB_1) && defined(USE_THUMB_2)
#error "USE_THUMB_1 and USE_THUMB_2 can't be defined together."
#endif
#if defined(__ARM_ARCH_4T__) || __ARM_ARCH >= 5
#define ARM_HAS_BX
#endif
#if !defined(__ARM_FEATURE_CLZ) && !defined(USE_THUMB_1) && \
(__ARM_ARCH >= 6 || (__ARM_ARCH == 5 && !defined(__ARM_ARCH_5__)))
#define __ARM_FEATURE_CLZ
#endif
#ifdef ARM_HAS_BX
#define JMP(r) bx r
#define JMPc(r, c) bx##c r
#else
#define JMP(r) mov pc, r
#define JMPc(r, c) mov##c pc, r
#endif
// pop {pc} can't switch Thumb mode on ARMv4T
#if __ARM_ARCH >= 5
#define POP_PC() pop {pc}
#else
#define POP_PC() \
pop {ip}; \
JMP(ip)
#endif
#if defined(USE_THUMB_2)
#define WIDE(op) op.w
#else
#define WIDE(op) op
#endif
#if defined(__ARM_FEATURE_PAC_DEFAULT) && defined(__ARM_FEATURE_BTI_DEFAULT)
#define PACBTI_LANDING pacbti r12, lr, sp
#elif defined(__ARM_FEATURE_PAC_DEFAULT)
#define PACBTI_LANDING pac r12, lr, sp
#elif defined(__ARM_FEATURE_BTI_DEFAULT)
#define PACBTI_LANDING bti
#else
#define PACBTI_LANDING
#endif
#else // !defined(__arm)
#define DECLARE_FUNC_ENCODING
#define DEFINE_CODE_STATE
#endif
#define GLUE2_(a, b) a##b
#define GLUE(a, b) GLUE2_(a, b)
#define GLUE2(a, b) GLUE2_(a, b)
#define GLUE3_(a, b, c) a##b##c
#define GLUE3(a, b, c) GLUE3_(a, b, c)
#define GLUE4_(a, b, c, d) a##b##c##d
#define GLUE4(a, b, c, d) GLUE4_(a, b, c, d)
#define SYMBOL_NAME(name) GLUE(__USER_LABEL_PREFIX__, name)
#ifndef __arm64ec__
#define FUNC_SYMBOL(name) name
#else
// On ARM64EC, function names and calls (but not address-taking or data symbol
// references) use symbols prefixed with "#".
#define QUOTE(a) #a
#define STR(a) QUOTE(a)
#define HASH #
#define FUNC_SYMBOL(name) STR(GLUE2(HASH, name))
#endif
#ifdef VISIBILITY_HIDDEN
#define DECLARE_SYMBOL_VISIBILITY(name) \
HIDDEN(SYMBOL_NAME(name)) SEPARATOR
#define DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name) \
HIDDEN(name) SEPARATOR
#else
#define DECLARE_SYMBOL_VISIBILITY(name)
#define DECLARE_SYMBOL_VISIBILITY_UNMANGLED(name)
#endif
#define DEFINE_COMPILERRT_FUNCTION(name) \
DEFINE_CODE_STATE \
FILE_LEVEL_DIRECTIVE SEPARATOR \
.globl FUNC_SYMBOL(SYMBOL_NAME(name)) SEPARATOR \
SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR \
DECLARE_SYMBOL_VISIBILITY(name) \
DECLARE_FUNC_ENCODING \
FUNC_SYMBOL(SYMBOL_NAME(name)):
#define DEFINE_COMPILERRT_THUMB_FUNCTION(name) \
DEFINE_CODE_STATE \
FILE_LEVEL_DIRECTIVE SEPARATOR \
.globl FUNC_SYMBOL(SYMBOL_NAME(name)) SEPARATOR \
SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR \
DECLARE_SYMBOL_VISIBILITY(name) SEPARATOR \
.thumb_func SEPARATOR \
FUNC_SYMBOL(SYMBOL_NAME(name)):
#define DEFINE_COMPILERRT_PRIVATE_FUNCTION(name) \
DEFINE_CODE_STATE \
FILE_LEVEL_DIRECTIVE SEPARATOR \
.globl FUNC_SYMBOL(SYMBOL_NAME(name)) SEPARATOR \
SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR \
HIDDEN(SYMBOL_NAME(name)) SEPARATOR \
DECLARE_FUNC_ENCODING \
FUNC_SYMBOL(SYMBOL_NAME(name)):
#define DEFINE_COMPILERRT_PRIVATE_FUNCTION_UNMANGLED(name) \
DEFINE_CODE_STATE \
.globl FUNC_SYMBOL(name) SEPARATOR \
SYMBOL_IS_FUNC(name) SEPARATOR \
HIDDEN(name) SEPARATOR \
DECLARE_FUNC_ENCODING \
FUNC_SYMBOL(name):
#define DEFINE_COMPILERRT_OUTLINE_FUNCTION_UNMANGLED(name) \
DEFINE_CODE_STATE \
FUNC_ALIGN \
.globl FUNC_SYMBOL(name) SEPARATOR \
SYMBOL_IS_FUNC(name) SEPARATOR \
DECLARE_SYMBOL_VISIBILITY_UNMANGLED(FUNC_SYMBOL(name)) SEPARATOR \
DECLARE_FUNC_ENCODING \
FUNC_SYMBOL(name): \
SEPARATOR CFI_START \
SEPARATOR BTI_C
#define DEFINE_COMPILERRT_FUNCTION_ALIAS(name, target) \
.globl FUNC_SYMBOL(SYMBOL_NAME(name)) SEPARATOR \
SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR \
DECLARE_SYMBOL_VISIBILITY(name) SEPARATOR \
.set FUNC_SYMBOL(SYMBOL_NAME(name)), FUNC_SYMBOL(target) SEPARATOR
#if defined(__ARM_EABI__)
#define DEFINE_AEABI_FUNCTION_ALIAS(aeabi_name, name) \
DEFINE_COMPILERRT_FUNCTION_ALIAS(aeabi_name, name)
#else
#define DEFINE_AEABI_FUNCTION_ALIAS(aeabi_name, name)
#endif
#ifdef __ELF__
#define END_COMPILERRT_FUNCTION(name) \
.size SYMBOL_NAME(name), . - SYMBOL_NAME(name)
#define END_COMPILERRT_OUTLINE_FUNCTION(name) \
CFI_END SEPARATOR \
.size SYMBOL_NAME(name), . - SYMBOL_NAME(name)
#else
#define END_COMPILERRT_FUNCTION(name)
#define END_COMPILERRT_OUTLINE_FUNCTION(name) \
CFI_END
#endif
#ifdef __arm__
#include "int_endianness.h"
#if _YUGA_BIG_ENDIAN
#define VMOV_TO_DOUBLE(dst, src0, src1) vmov dst, src1, src0 SEPARATOR
#define VMOV_FROM_DOUBLE(dst0, dst1, src) vmov dst1, dst0, src SEPARATOR
#else
#define VMOV_TO_DOUBLE(dst, src0, src1) vmov dst, src0, src1 SEPARATOR
#define VMOV_FROM_DOUBLE(dst0, dst1, src) vmov dst0, dst1, src SEPARATOR
#endif
#endif
#endif // COMPILERRT_ASSEMBLY_H
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