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Add frame pointer recovery to the AMD64 Stackwalker.

Browse Source 
BUG=https://code.google.com/p/chromium/issues/detail?id=393594
R=mark@chromium.org

Review URL: https://breakpad.appspot.com/10664002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1350 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
rsesek@chromium.org
2014-07-18 00:27:49 +00:00
parent d91bd8d23a
commit 6c57bc19a5
3 changed files with 61 additions and 3 deletions
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54
src/processor/stackwalker_amd64.cc
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@@ -147,6 +147,52 @@ StackFrameAMD64* StackwalkerAMD64::GetCallerByCFIFrameInfo(
return frame.release();
}
StackFrameAMD64* StackwalkerAMD64::GetCallerByFramePointerRecovery(
const vector<StackFrame*>& frames) {
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
uint64_t last_rsp = last_frame->context.rsp;
uint64_t last_rbp = last_frame->context.rbp;
// Assume the presence of a frame pointer. This is not mandated by the
// AMD64 ABI, c.f. section 3.2.2 footnote 7, though it is typical for
// compilers to still preserve the frame pointer and not treat %rbp as a
// general purpose register.
//
// With this assumption, the CALL instruction pushes the return address
// onto the stack and sets %rip to the procedure to enter. The procedure
// then establishes the stack frame with a prologue that PUSHes the current
// %rbp onto the stack, MOVes the current %rsp to %rbp, and then allocates
// space for any local variables. Using this procedure linking information,
// it is possible to locate frame information for the callee:
//
// %caller_rsp = *(%callee_rbp + 16)
// %caller_rip = *(%callee_rbp + 8)
// %caller_rbp = *(%callee_rbp)
uint64_t caller_rip, caller_rbp;
if (memory_->GetMemoryAtAddress(last_rbp + 8, &caller_rip) &&
memory_->GetMemoryAtAddress(last_rbp, &caller_rbp)) {
uint64_t caller_rsp = last_rbp + 16;
// Simple sanity check that the stack is growing downwards as expected.
if (caller_rbp < last_rbp || caller_rsp < last_rsp)
return NULL;
StackFrameAMD64* frame = new StackFrameAMD64();
frame->trust = StackFrame::FRAME_TRUST_FP;
frame->context = last_frame->context;
frame->context.rip = caller_rip;
frame->context.rsp = caller_rsp;
frame->context.rbp = caller_rbp;
frame->context_validity = StackFrameAMD64::CONTEXT_VALID_RIP |
StackFrameAMD64::CONTEXT_VALID_RSP |
StackFrameAMD64::CONTEXT_VALID_RBP;
return frame;
}
return NULL;
}
StackFrameAMD64* StackwalkerAMD64::GetCallerByStackScan(
const vector<StackFrame*> &frames) {
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
@@ -214,8 +260,12 @@ StackFrame* StackwalkerAMD64::GetCallerFrame(const CallStack* stack,
if (cfi_frame_info.get())
new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
// If CFI failed, or there wasn't CFI available, fall back
// to stack scanning.
// If CFI was not available or failed, try using frame pointer recovery.
if (!new_frame.get()) {
new_frame.reset(GetCallerByFramePointerRecovery(frames));
}
// If all else fails, fall back to stack scanning.
if (stack_scan_allowed && !new_frame.get()) {
new_frame.reset(GetCallerByStackScan(frames));
}