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-rw-r--r--lib/sanitizer_common/sanitizer_stacktrace.cpp133
1 files changed, 133 insertions, 0 deletions
diff --git a/lib/sanitizer_common/sanitizer_stacktrace.cpp b/lib/sanitizer_common/sanitizer_stacktrace.cpp
new file mode 100644
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+++ b/lib/sanitizer_common/sanitizer_stacktrace.cpp
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+//===-- sanitizer_stacktrace.cpp ------------------------------------------===//
+//
+// 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 is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common.h"
+#include "sanitizer_flags.h"
+#include "sanitizer_stacktrace.h"
+
+namespace __sanitizer {
+
+uptr StackTrace::GetNextInstructionPc(uptr pc) {
+#if defined(__sparc__) || defined(__mips__)
+ return pc + 8;
+#elif defined(__powerpc__) || defined(__arm__) || defined(__aarch64__)
+ return pc + 4;
+#else
+ return pc + 1;
+#endif
+}
+
+uptr StackTrace::GetCurrentPc() {
+ return GET_CALLER_PC();
+}
+
+void BufferedStackTrace::Init(const uptr *pcs, uptr cnt, uptr extra_top_pc) {
+ size = cnt + !!extra_top_pc;
+ CHECK_LE(size, kStackTraceMax);
+ internal_memcpy(trace_buffer, pcs, cnt * sizeof(trace_buffer[0]));
+ if (extra_top_pc)
+ trace_buffer[cnt] = extra_top_pc;
+ top_frame_bp = 0;
+}
+
+// Sparc implemention is in its own file.
+#if !defined(__sparc__)
+
+// In GCC on ARM bp points to saved lr, not fp, so we should check the next
+// cell in stack to be a saved frame pointer. GetCanonicFrame returns the
+// pointer to saved frame pointer in any case.
+static inline uhwptr *GetCanonicFrame(uptr bp,
+ uptr stack_top,
+ uptr stack_bottom) {
+ CHECK_GT(stack_top, stack_bottom);
+#ifdef __arm__
+ if (!IsValidFrame(bp, stack_top, stack_bottom)) return 0;
+ uhwptr *bp_prev = (uhwptr *)bp;
+ if (IsValidFrame((uptr)bp_prev[0], stack_top, stack_bottom)) return bp_prev;
+ // The next frame pointer does not look right. This could be a GCC frame, step
+ // back by 1 word and try again.
+ if (IsValidFrame((uptr)bp_prev[-1], stack_top, stack_bottom))
+ return bp_prev - 1;
+ // Nope, this does not look right either. This means the frame after next does
+ // not have a valid frame pointer, but we can still extract the caller PC.
+ // Unfortunately, there is no way to decide between GCC and LLVM frame
+ // layouts. Assume LLVM.
+ return bp_prev;
+#else
+ return (uhwptr*)bp;
+#endif
+}
+
+void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
+ uptr stack_bottom, u32 max_depth) {
+ // TODO(yln): add arg sanity check for stack_top/stack_bottom
+ CHECK_GE(max_depth, 2);
+ const uptr kPageSize = GetPageSizeCached();
+ trace_buffer[0] = pc;
+ size = 1;
+ if (stack_top < 4096) return; // Sanity check for stack top.
+ uhwptr *frame = GetCanonicFrame(bp, stack_top, stack_bottom);
+ // Lowest possible address that makes sense as the next frame pointer.
+ // Goes up as we walk the stack.
+ uptr bottom = stack_bottom;
+ // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
+ while (IsValidFrame((uptr)frame, stack_top, bottom) &&
+ IsAligned((uptr)frame, sizeof(*frame)) &&
+ size < max_depth) {
+#ifdef __powerpc__
+ // PowerPC ABIs specify that the return address is saved at offset
+ // 16 of the *caller's* stack frame. Thus we must dereference the
+ // back chain to find the caller frame before extracting it.
+ uhwptr *caller_frame = (uhwptr*)frame[0];
+ if (!IsValidFrame((uptr)caller_frame, stack_top, bottom) ||
+ !IsAligned((uptr)caller_frame, sizeof(uhwptr)))
+ break;
+ uhwptr pc1 = caller_frame[2];
+#elif defined(__s390__)
+ uhwptr pc1 = frame[14];
+#else
+ uhwptr pc1 = frame[1];
+#endif
+ // Let's assume that any pointer in the 0th page (i.e. <0x1000 on i386 and
+ // x86_64) is invalid and stop unwinding here. If we're adding support for
+ // a platform where this isn't true, we need to reconsider this check.
+ if (pc1 < kPageSize)
+ break;
+ if (pc1 != pc) {
+ trace_buffer[size++] = (uptr) pc1;
+ }
+ bottom = (uptr)frame;
+ frame = GetCanonicFrame((uptr)frame[0], stack_top, bottom);
+ }
+}
+
+#endif // !defined(__sparc__)
+
+void BufferedStackTrace::PopStackFrames(uptr count) {
+ CHECK_LT(count, size);
+ size -= count;
+ for (uptr i = 0; i < size; ++i) {
+ trace_buffer[i] = trace_buffer[i + count];
+ }
+}
+
+static uptr Distance(uptr a, uptr b) { return a < b ? b - a : a - b; }
+
+uptr BufferedStackTrace::LocatePcInTrace(uptr pc) {
+ uptr best = 0;
+ for (uptr i = 1; i < size; ++i) {
+ if (Distance(trace[i], pc) < Distance(trace[best], pc)) best = i;
+ }
+ return best;
+}
+
+} // namespace __sanitizer