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Handle frame pointer omission, (#21), part 4 (final part!): FPO stackwalker.

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r=bryner
 - This change allows Airbag to properly walk win32 stacks produced by code
   built with MSVC's frame pointer omission optimization (/Oy).  This
   optimization is enabled at /O1 and /O2.
 - There too many interface and file format changes to list here.

http://groups.google.com/group/airbag-dev/browse_thread/thread/85ce85bfa8457ece


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@42 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
mmentovai 2006-10-20 01:46:38 +00:00
parent 5afd60b067
commit 246f406828
33 changed files with 2643 additions and 1744 deletions
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94
src/processor/stackwalker_ppc.cc
View file

@ -35,6 +35,8 @@
#include "processor/stackwalker_ppc.h"
#include "google/call_stack.h"
#include "google/stack_frame_cpu.h"
#include "processor/minidump.h"
namespace google_airbag {
@ -55,65 +57,77 @@ StackwalkerPPC::StackwalkerPPC(const MDRawContextPPC *context,
}
bool StackwalkerPPC::GetContextFrame(StackFrame *frame) {
if (!context_ || !memory_ || !frame)
return false;
StackFrame* StackwalkerPPC::GetContextFrame() {
if (!context_ || !memory_)
return NULL;
// The stack frame and instruction pointers are stored directly in
// registers, so pull them straight out of the CPU context structure.
frame->frame_pointer = context_->gpr[1];
frame->instruction = context_->srr0;
StackFramePPC *frame = new StackFramePPC();
return true;
// The instruction pointer is stored directly in a register, so pull it
// straight out of the CPU context structure.
frame->context = *context_;
frame->context_validity = StackFramePPC::CONTEXT_VALID_ALL;
frame->instruction = frame->context.srr0;
return frame;
}
bool StackwalkerPPC::GetCallerFrame(StackFrame *frame,
const StackFrames *walked_frames) {
if (!memory_ || !frame || !walked_frames)
return false;
StackFrame* StackwalkerPPC::GetCallerFrame(const CallStack *stack) {
if (!memory_ || !stack)
return NULL;
// The stack frame and instruction pointers for previous frames are saved
// on the stack. The typical ppc calling convention is for the called
// procedure to store its return address in the calling procedure's stack
// frame at 8(%r1), and to allocate its own stack frame by decrementing %r1
// (the stack pointer) and saving the old value of %r1 at 0(%r1). Because
// the ppc has no hardware stack, there is no distinction between the
// stack pointer and frame pointer, and what is typically thought of as
// the frame pointer on an x86 is usually referred to as the stack pointer
// on a ppc.
// The instruction pointers for previous frames are saved on the stack.
// The typical ppc calling convention is for the called procedure to store
// its return address in the calling procedure's stack frame at 8(%r1),
// and to allocate its own stack frame by decrementing %r1 (the stack
// pointer) and saving the old value of %r1 at 0(%r1). Because the ppc has
// no hardware stack, there is no distinction between the stack pointer and
// frame pointer, and what is typically thought of as the frame pointer on
// an x86 is usually referred to as the stack pointer on a ppc.
u_int32_t last_stack_pointer = walked_frames->back().frame_pointer;
// Don't pass frame.frame_pointer or frame.instruction directly
// ReadMemory, because their types are too wide (64-bit), and we
// specifically want to read 32-bit quantities for both.
u_int32_t stack_pointer;
if (!memory_->GetMemoryAtAddress(last_stack_pointer, &stack_pointer))
return false;
StackFramePPC *last_frame = static_cast<StackFramePPC*>(
stack->frames()->back());
// A caller frame must reside higher in memory than its callee frames.
// Anything else is an error, or an indication that we've reached the
// end of the stack.
if (stack_pointer <= last_stack_pointer)
return false;
u_int32_t instruction;
if (!memory_->GetMemoryAtAddress(stack_pointer + 8, &instruction))
return false;
u_int32_t stack_pointer;
if (!memory_->GetMemoryAtAddress(last_frame->context.gpr[1],
&stack_pointer) ||
stack_pointer <= last_frame->context.gpr[1]) {
return NULL;
}
// Mac OS X/Darwin gives 1 as the return address from the bottom-most
// frame in a stack (a thread's entry point). I haven't found any
// documentation on this, but 0 or 1 would be bogus return addresses,
// so check for them here and return false (end of stack) when they're
// hit to avoid having a phantom frame.
if (instruction <= 1)
return false;
u_int32_t instruction;
if (!memory_->GetMemoryAtAddress(stack_pointer + 8, &instruction) ||
instruction <= 1) {
return NULL;
}
frame->frame_pointer = stack_pointer;
frame->instruction = instruction;
StackFramePPC *frame = new StackFramePPC();
return true;
frame->context = last_frame->context;
frame->context.srr0 = instruction;
frame->context.gpr[1] = stack_pointer;
frame->context_validity = StackFramePPC::CONTEXT_VALID_SRR0 |
StackFramePPC::CONTEXT_VALID_GPR1;
// frame->context.srr0 is the return address, which is one instruction
// past the branch that caused us to arrive at the callee. Set
// frame_ppc->instruction to four less than that. Since all ppc
// instructions are 4 bytes wide, this is the address of the branch
// instruction. This allows source line information to match up with the
// line that contains a function call. Callers that require the exact
// return address value may access the context.srr0 field of StackFramePPC.
frame->instruction = frame->context.srr0 - 4;
return frame;
}