forked from OSchip/llvm-project
134 lines
4.6 KiB
C++
134 lines
4.6 KiB
C++
//===-- sanitizer_stacktrace.cpp ------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is shared between AddressSanitizer and ThreadSanitizer
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// run-time libraries.
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//===----------------------------------------------------------------------===//
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#include "sanitizer_common.h"
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#include "sanitizer_flags.h"
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#include "sanitizer_stacktrace.h"
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namespace __sanitizer {
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uptr StackTrace::GetNextInstructionPc(uptr pc) {
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#if defined(__sparc__) || defined(__mips__)
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return pc + 8;
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#elif defined(__powerpc__) || defined(__arm__) || defined(__aarch64__)
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return pc + 4;
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#else
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return pc + 1;
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#endif
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}
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uptr StackTrace::GetCurrentPc() {
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return GET_CALLER_PC();
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}
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void BufferedStackTrace::Init(const uptr *pcs, uptr cnt, uptr extra_top_pc) {
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size = cnt + !!extra_top_pc;
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CHECK_LE(size, kStackTraceMax);
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internal_memcpy(trace_buffer, pcs, cnt * sizeof(trace_buffer[0]));
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if (extra_top_pc)
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trace_buffer[cnt] = extra_top_pc;
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top_frame_bp = 0;
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}
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// Sparc implemention is in its own file.
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#if !defined(__sparc__)
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// In GCC on ARM bp points to saved lr, not fp, so we should check the next
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// cell in stack to be a saved frame pointer. GetCanonicFrame returns the
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// pointer to saved frame pointer in any case.
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static inline uhwptr *GetCanonicFrame(uptr bp,
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uptr stack_top,
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uptr stack_bottom) {
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CHECK_GT(stack_top, stack_bottom);
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#ifdef __arm__
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if (!IsValidFrame(bp, stack_top, stack_bottom)) return 0;
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uhwptr *bp_prev = (uhwptr *)bp;
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if (IsValidFrame((uptr)bp_prev[0], stack_top, stack_bottom)) return bp_prev;
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// The next frame pointer does not look right. This could be a GCC frame, step
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// back by 1 word and try again.
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if (IsValidFrame((uptr)bp_prev[-1], stack_top, stack_bottom))
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return bp_prev - 1;
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// Nope, this does not look right either. This means the frame after next does
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// not have a valid frame pointer, but we can still extract the caller PC.
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// Unfortunately, there is no way to decide between GCC and LLVM frame
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// layouts. Assume LLVM.
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return bp_prev;
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#else
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return (uhwptr*)bp;
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#endif
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}
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void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
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uptr stack_bottom, u32 max_depth) {
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// TODO(yln): add arg sanity check for stack_top/stack_bottom
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CHECK_GE(max_depth, 2);
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const uptr kPageSize = GetPageSizeCached();
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trace_buffer[0] = pc;
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size = 1;
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if (stack_top < 4096) return; // Sanity check for stack top.
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uhwptr *frame = GetCanonicFrame(bp, stack_top, stack_bottom);
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// Lowest possible address that makes sense as the next frame pointer.
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// Goes up as we walk the stack.
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uptr bottom = stack_bottom;
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// Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
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while (IsValidFrame((uptr)frame, stack_top, bottom) &&
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IsAligned((uptr)frame, sizeof(*frame)) &&
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size < max_depth) {
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#ifdef __powerpc__
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// PowerPC ABIs specify that the return address is saved at offset
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// 16 of the *caller's* stack frame. Thus we must dereference the
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// back chain to find the caller frame before extracting it.
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uhwptr *caller_frame = (uhwptr*)frame[0];
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if (!IsValidFrame((uptr)caller_frame, stack_top, bottom) ||
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!IsAligned((uptr)caller_frame, sizeof(uhwptr)))
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break;
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uhwptr pc1 = caller_frame[2];
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#elif defined(__s390__)
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uhwptr pc1 = frame[14];
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#else
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uhwptr pc1 = frame[1];
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#endif
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// Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and
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// x86_64) is invalid and stop unwinding here. If we're adding support for
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// a platform where this isn't true, we need to reconsider this check.
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if (pc1 < kPageSize)
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break;
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if (pc1 != pc) {
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trace_buffer[size++] = (uptr) pc1;
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}
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bottom = (uptr)frame;
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frame = GetCanonicFrame((uptr)frame[0], stack_top, bottom);
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}
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}
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#endif // !defined(__sparc__)
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void BufferedStackTrace::PopStackFrames(uptr count) {
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CHECK_LT(count, size);
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size -= count;
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for (uptr i = 0; i < size; ++i) {
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trace_buffer[i] = trace_buffer[i + count];
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}
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}
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static uptr Distance(uptr a, uptr b) { return a < b ? b - a : a - b; }
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uptr BufferedStackTrace::LocatePcInTrace(uptr pc) {
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uptr best = 0;
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for (uptr i = 1; i < size; ++i) {
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if (Distance(trace[i], pc) < Distance(trace[best], pc)) best = i;
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}
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return best;
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}
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} // namespace __sanitizer
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