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

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+:649314b44df4
+// 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_arm.cc: arm-specific stackwalker.
+//
+// See stackwalker_arm.h for documentation.
+//
+// Author: Mark Mentovai, Ted Mielczarek, Jim Blandy
+#include <vector>
+#include "common/scoped_ptr.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/source_line_resolver_interface.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+#include "processor/cfi_frame_info.h"
+#include "common/logging.h"
+#include "processor/stackwalker_arm.h"
+namespace google_breakpad {
+StackwalkerARM::StackwalkerARM(const SystemInfo* system_info,
+const MDRawContextARM* context,
+int fp_register,
+MemoryRegion* memory,
+const CodeModules* modules,
+StackFrameSymbolizer* resolver_helper)
+: Stackwalker(system_info, memory, modules, resolver_helper),
+context_(context), fp_register_(fp_register),
+context_frame_validity_(StackFrameARM::CONTEXT_VALID_ALL) { }
+StackFrame* StackwalkerARM::GetContextFrame() {
+if (!context_) {
+BPLOG(ERROR) << "Can't get context frame without context";
+return NULL;
+}
+StackFrameARM* frame = new StackFrameARM();
+// The instruction pointer is stored directly in a register (r15), so pull it
+// straight out of the CPU context structure.
+frame->context = *context_;
+frame->context_validity = context_frame_validity_;
+frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
+frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC];
+return frame;
+}
+StackFrameARM* StackwalkerARM::GetCallerByCFIFrameInfo(
+const vector<StackFrame*> &frames,
+CFIFrameInfo* cfi_frame_info) {
+StackFrameARM* last_frame = static_cast<StackFrameARM*>(frames.back());
+static const UniqueString *register_names[] = {
+ToUniqueString("r0"),  ToUniqueString("r1"),
+ToUniqueString("r2"),  ToUniqueString("r3"),
+ToUniqueString("r4"),  ToUniqueString("r5"),
+ToUniqueString("r6"),  ToUniqueString("r7"),
+ToUniqueString("r8"),  ToUniqueString("r9"),
+ToUniqueString("r10"), ToUniqueString("r11"),
+ToUniqueString("r12"), ToUniqueString("sp"),
+ToUniqueString("lr"),  ToUniqueString("pc"),
+ToUniqueString("f0"),  ToUniqueString("f1"),
+ToUniqueString("f2"),  ToUniqueString("f3"),
+ToUniqueString("f4"),  ToUniqueString("f5"),
+ToUniqueString("f6"),  ToUniqueString("f7"),
+ToUniqueString("fps"), ToUniqueString("cpsr"),
+NULL
+};
+// Populate a dictionary with the valid register values in last_frame.
+CFIFrameInfo::RegisterValueMap<uint32_t> callee_registers;
+for (int i = 0; register_names[i]; i++)
+if (last_frame->context_validity & StackFrameARM::RegisterValidFlag(i))
+callee_registers.set(register_names[i], last_frame->context.iregs[i]);
+// Use the STACK CFI data to recover the caller's register values.
+CFIFrameInfo::RegisterValueMap<uint32_t> caller_registers;
+if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_,
+&caller_registers))
+return NULL;
+// Construct a new stack frame given the values the CFI recovered.
+scoped_ptr<StackFrameARM> frame(new StackFrameARM());
+for (int i = 0; register_names[i]; i++) {
+bool found = false;
+uint32_t v = caller_registers.get(&found, register_names[i]);
+if (found) {
+// We recovered the value of this register; fill the context with the
+// value from caller_registers.
+frame->context_validity |= StackFrameARM::RegisterValidFlag(i);
+frame->context.iregs[i] = v;
+} else if (4 <= i && i <= 11 && (last_frame->context_validity &
+StackFrameARM::RegisterValidFlag(i))) {
+// If the STACK CFI data doesn't mention some callee-saves register, and
+// it is valid in the callee, assume the callee has not yet changed it.
+// Registers r4 through r11 are callee-saves, according to the Procedure
+// Call Standard for the ARM Architecture, which the Linux ABI follows.
+frame->context_validity |= StackFrameARM::RegisterValidFlag(i);
+frame->context.iregs[i] = last_frame->context.iregs[i];
+}
+}
+// If the CFI doesn't recover the PC explicitly, then use .ra.
+if (!(frame->context_validity & StackFrameARM::CONTEXT_VALID_PC)) {
+bool found = false;
+uint32_t v = caller_registers.get(&found, ustr__ZDra());
+if (found) {
+if (fp_register_ == -1) {
+frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
+frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = v;
+} else {
+// The CFI updated the link register and not the program counter.
+// Handle getting the program counter from the link register.
+frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
+frame->context_validity |= StackFrameARM::CONTEXT_VALID_LR;
+frame->context.iregs[MD_CONTEXT_ARM_REG_LR] = v;
+frame->context.iregs[MD_CONTEXT_ARM_REG_PC] =
+last_frame->context.iregs[MD_CONTEXT_ARM_REG_LR];
+}
+}
+}
+// If the CFI doesn't recover the SP explicitly, then use .cfa.
+if (!(frame->context_validity & StackFrameARM::CONTEXT_VALID_SP)) {
+bool found = false;
+uint32_t v = caller_registers.get(&found, ustr__ZDcfa());
+if (found) {
+frame->context_validity |= StackFrameARM::CONTEXT_VALID_SP;
+frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = v;
+}
+}
+// If we didn't recover the PC and the SP, then the frame isn't very useful.
+static const int essentials = (StackFrameARM::CONTEXT_VALID_SP
+| StackFrameARM::CONTEXT_VALID_PC);
+if ((frame->context_validity & essentials) != essentials)
+return NULL;
+frame->trust = StackFrame::FRAME_TRUST_CFI;
+return frame.release();
+}
+StackFrameARM* StackwalkerARM::GetCallerByStackScan(
+const vector<StackFrame*> &frames) {
+StackFrameARM* last_frame = static_cast<StackFrameARM*>(frames.back());
+uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
+uint32_t caller_sp, caller_pc;
+// When searching for the caller of the context frame,
+// allow the scanner to look farther down the stack.
+const int kRASearchWords = frames.size() == 1 ?
+Stackwalker::kRASearchWords * 4 :
+Stackwalker::kRASearchWords;
+if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc,
+kRASearchWords)) {
+// No plausible return address was found.
+return NULL;
+}
+// ScanForReturnAddress found a reasonable return address. Advance
+// %sp to the location above the one where the return address was
+// found.
+caller_sp += 4;
+// Create a new stack frame (ownership will be transferred to the caller)
+// and fill it in.
+StackFrameARM* frame = new StackFrameARM();
+frame->trust = StackFrame::FRAME_TRUST_SCAN;
+frame->context = last_frame->context;
+frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = caller_pc;
+frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = caller_sp;
+frame->context_validity = StackFrameARM::CONTEXT_VALID_PC |
+StackFrameARM::CONTEXT_VALID_SP;
+return frame;
+}
+StackFrameARM* StackwalkerARM::GetCallerByFramePointer(
+const vector<StackFrame*> &frames) {
+StackFrameARM* last_frame = static_cast<StackFrameARM*>(frames.back());
+if (!(last_frame->context_validity &
+StackFrameARM::RegisterValidFlag(fp_register_))) {
+return NULL;
+}
+uint32_t last_fp = last_frame->context.iregs[fp_register_];
+uint32_t caller_fp = 0;
+if (last_fp && !memory_->GetMemoryAtAddress(last_fp, &caller_fp)) {
+BPLOG(ERROR) << "Unable to read caller_fp from last_fp: 0x"
+<< std::hex << last_fp;
+return NULL;
+}
+uint32_t caller_lr = 0;
+if (last_fp && !memory_->GetMemoryAtAddress(last_fp + 4, &caller_lr)) {
+BPLOG(ERROR) << "Unable to read caller_lr from last_fp + 4: 0x"
+<< std::hex << (last_fp + 4);
+return NULL;
+}
+uint32_t caller_sp = last_fp ? last_fp + 8 :
+last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
+// Create a new stack frame (ownership will be transferred to the caller)
+// and fill it in.
+StackFrameARM* frame = new StackFrameARM();
+frame->trust = StackFrame::FRAME_TRUST_FP;
+frame->context = last_frame->context;
+frame->context.iregs[fp_register_] = caller_fp;
+frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = caller_sp;
+frame->context.iregs[MD_CONTEXT_ARM_REG_PC] =
+last_frame->context.iregs[MD_CONTEXT_ARM_REG_LR];
+frame->context.iregs[MD_CONTEXT_ARM_REG_LR] = caller_lr;
+frame->context_validity = StackFrameARM::CONTEXT_VALID_PC |
+StackFrameARM::CONTEXT_VALID_LR |
+StackFrameARM::RegisterValidFlag(fp_register_) |
+StackFrameARM::CONTEXT_VALID_SP;
+return frame;
+}
+StackFrame* StackwalkerARM::GetCallerFrame(const CallStack* stack,
+bool stack_scan_allowed) {
+if (!memory_ || !stack) {
+BPLOG(ERROR) << "Can't get caller frame without memory or stack";
+return NULL;
+}
+const vector<StackFrame*> &frames = *stack->frames();
+StackFrameARM* last_frame = static_cast<StackFrameARM*>(frames.back());
+scoped_ptr<StackFrameARM> frame;
+// See if there is DWARF call frame information covering this address.
+scoped_ptr<CFIFrameInfo> cfi_frame_info(
+frame_symbolizer_->FindCFIFrameInfo(last_frame));
+if (cfi_frame_info.get())
+frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
+// If CFI failed, or there wasn't CFI available, fall back
+// to frame pointer, if this is configured.
+if (fp_register_ >= 0 && !frame.get())
+frame.reset(GetCallerByFramePointer(frames));
+// If everuthing failed, fall back to stack scanning.
+if (stack_scan_allowed && !frame.get())
+frame.reset(GetCallerByStackScan(frames));
+// If nothing worked, tell the caller.
+if (!frame.get())
+return NULL;
+// An instruction address of zero marks the end of the stack.
+if (frame->context.iregs[MD_CONTEXT_ARM_REG_PC] == 0)
+return NULL;
+// If the new stack pointer is at a lower address than the old, then
+// that's clearly incorrect. Treat this as end-of-stack to enforce
+// progress and avoid infinite loops.
+if (frame->context.iregs[MD_CONTEXT_ARM_REG_SP]
+< last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP])
+return NULL;
+// The new frame's context's PC is the return address, which is one
+// instruction past the instruction that caused us to arrive at the
+// callee. Set new_frame->instruction to one less than the PC. This won't
+// reference the beginning of the call instruction, but it's at least
+// within it, which is sufficient to get the source line information to
+// match up with the line that contains the function call. Callers that
+// require the exact return address value may access
+// frame->context.iregs[MD_CONTEXT_ARM_REG_PC].
+frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC] - 2;
+return frame.release();
+}
+}  // namespace google_breakpad

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

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