================ @@ -0,0 +1,127 @@ +//===--- RunOnNewStack.cpp - Crash Recovery -------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/ProgramStack.h" +#include "llvm/Config/config.h" +#include "llvm/Support/Compiler.h" + +#ifdef LLVM_ON_UNIX +# include <sys/resource.h> // for getrlimit +#endif + +#ifdef _MSC_VER +# include <intrin.h> // for _AddressOfReturnAddress +#endif + +#ifndef LLVM_HAS_SPLIT_STACKS +# include "llvm/Support/thread.h" +#endif + +using namespace llvm; + +uintptr_t llvm::getStackPointer() { +#if __GNUC__ || __has_builtin(__builtin_frame_address) + return (uintptr_t)__builtin_frame_address(0); +#elif defined(_MSC_VER) + return (uintptr_t)_AddressOfReturnAddress(); +#else + volatile char CharOnStack = 0; + // The volatile store here is intended to escape the local variable, to + // prevent the compiler from optimizing CharOnStack into anything other + // than a char on the stack. + // + // Tested on: MSVC 2015 - 2019, GCC 4.9 - 9, Clang 3.2 - 9, ICC 13 - 19. + char *volatile Ptr = &CharOnStack; + return (uintptr_t)Ptr; +#endif +} + +unsigned llvm::getDefaultStackSize() { +#ifdef LLVM_ON_UNIX + rlimit RL; + getrlimit(RLIMIT_STACK, &RL); + return RL.rlim_cur; +#else + // Clang recursively parses, instantiates templates, and evaluates constant + // expressions. We've found 8MiB to be a reasonable stack size given the way + // Clang works and the way C++ is commonly written. + return 8 << 20; +#endif +} + +// Not an anonymous namespace to avoid warning about undefined local function. +namespace llvm { +#ifdef LLVM_HAS_SPLIT_STACKS_AARCH64 +void runOnNewStackImpl(void *Stack, void (*Fn)(void *), void *Ctx) __asm__( + "_ZN4llvm17runOnNewStackImplEPvPFvS0_ES0_"); + +// This can't use naked functions because there is no way to know if cfi +// directives are being emitted or not. +// +// When adding new platforms it may be better to move to a .S file with macros +// for dealing with platform differences. +__asm__ ( + ".globl _ZN4llvm17runOnNewStackImplEPvPFvS0_ES0_\n\t" + ".p2align 2\n\t" + "_ZN4llvm17runOnNewStackImplEPvPFvS0_ES0_:\n\t" + ".cfi_startproc\n\t" + "mov x16, sp\n\t" + "sub x0, x0, #0x20\n\t" // subtract space from stack + "stp xzr, x16, [x0, #0x00]\n\t" // save old sp + "stp x29, x30, [x0, #0x10]\n\t" // save fp, lr + "mov sp, x0\n\t" // switch to new stack + "add x29, x0, #0x10\n\t" // switch to new frame + ".cfi_def_cfa w29, 16\n\t" ---------------- Bigcheese wrote:
The CFI info is about what `x29` points to, which is only valid after the assignment via `add`. I verified that stopping lldb between the `mov sp, x0` and `add x29, x0, #0x10` works. https://github.com/llvm/llvm-project/pull/136046 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
