The Tor Browser: comparison toolkit/crashreporter/google-breakpad/src/processor/stackwalker

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+// Copyright (c) 2010 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// stackwalker_ppc.cc: ppc-specific stackwalker.
+//
+// See stackwalker_ppc.h for documentation.
+//
+// Author: Mark Mentovai
+#include "processor/stackwalker_ppc.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "common/logging.h"
+namespace google_breakpad {
+StackwalkerPPC::StackwalkerPPC(const SystemInfo* system_info,
+const MDRawContextPPC* context,
+MemoryRegion* memory,
+const CodeModules* modules,
+StackFrameSymbolizer* resolver_helper)
+: Stackwalker(system_info, memory, modules, resolver_helper),
+context_(context) {
+if (memory_ && memory_->GetBase() + memory_->GetSize() - 1 > 0xffffffff) {
+// This implementation only covers 32-bit ppc CPUs.  The limits of the
+// supplied stack are invalid.  Mark memory_ = NULL, which will cause
+// stackwalking to fail.
+BPLOG(ERROR) << "Memory out of range for stackwalking: " <<
+HexString(memory_->GetBase()) << "+" <<
+HexString(memory_->GetSize());
+memory_ = NULL;
+}
+}
+StackFrame* StackwalkerPPC::GetContextFrame() {
+if (!context_) {
+BPLOG(ERROR) << "Can't get context frame without context";
+return NULL;
+}
+StackFramePPC* frame = new StackFramePPC();
+// 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->trust = StackFrame::FRAME_TRUST_CONTEXT;
+frame->instruction = frame->context.srr0;
+return frame;
+}
+StackFrame* StackwalkerPPC::GetCallerFrame(const CallStack* stack,
+bool stack_scan_allowed) {
+if (!memory_ || !stack) {
+BPLOG(ERROR) << "Can't get caller frame without memory or stack";
+return NULL;
+}
+// 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.
+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.
+uint32_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.
+uint32_t instruction;
+if (!memory_->GetMemoryAtAddress(stack_pointer + 8, &instruction) ||
+instruction <= 1) {
+return NULL;
+}
+StackFramePPC* frame = new StackFramePPC();
+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->trust = StackFrame::FRAME_TRUST_FP;
+// 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;
+}
+}  // namespace google_breakpad

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comparison: toolkit/crashreporter/google-breakpad/src/processor/stackwalker_ppc.cc

toolkit/crashreporter/google-breakpad/src/processor/stackwalker_ppc.cc