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

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+// Copyright (c) 2006, 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_selftest.cc: Tests StackwalkerX86 or StackwalkerPPC using the
+// running process' stack as test data, if running on an x86 or ppc and
+// compiled with gcc.  This test is not enabled in the "make check" suite
+// by default, because certain optimizations interfere with its proper
+// operation.  To turn it on, configure with --enable-selftest.
+//
+// Optimizations that cause problems:
+//  - stack frame reuse.  The Recursor function here calls itself with
+//    |return Recursor|.  When the caller's frame is reused, it will cause
+//    CountCallerFrames to correctly return the same number of frames
+//    in both the caller and callee.  This is considered an unexpected
+//    condition in the test, which expects a callee to have one more
+//    caller frame in the stack than its caller.
+//  - frame pointer omission.  Even with a stackwalker that understands
+//    this optimization, the code to harness debug information currently
+//    only exists to retrieve it from minidumps, not the current process.
+//
+// This test can also serve as a developmental and debugging aid if
+// PRINT_STACKS is defined.
+//
+// Author: Mark Mentovai
+#include "processor/logging.h"
+#if defined(__i386) && !defined(__i386__)
+#define __i386__
+#endif
+#if defined(__sparc) && !defined(__sparc__)
+#define __sparc__
+#endif
+#if (defined(__SUNPRO_CC) || defined(__GNUC__)) && \
+(defined(__i386__) || defined(__ppc__) || defined(__sparc__))
+#include <stdio.h>
+#include "common/scoped_ptr.h"
+#include "google_breakpad/common/breakpad_types.h"
+#include "google_breakpad/common/minidump_format.h"
+#include "google_breakpad/processor/basic_source_line_resolver.h"
+#include "google_breakpad/processor/call_stack.h"
+#include "google_breakpad/processor/code_module.h"
+#include "google_breakpad/processor/memory_region.h"
+#include "google_breakpad/processor/stack_frame.h"
+#include "google_breakpad/processor/stack_frame_cpu.h"
+using google_breakpad::BasicSourceLineResolver;
+using google_breakpad::CallStack;
+using google_breakpad::CodeModule;
+using google_breakpad::MemoryRegion;
+using google_breakpad::scoped_ptr;
+using google_breakpad::StackFrame;
+using google_breakpad::StackFramePPC;
+using google_breakpad::StackFrameX86;
+using google_breakpad::StackFrameSPARC;
+#if defined(__i386__)
+#include "processor/stackwalker_x86.h"
+using google_breakpad::StackwalkerX86;
+#elif defined(__ppc__)
+#include "processor/stackwalker_ppc.h"
+using google_breakpad::StackwalkerPPC;
+#elif defined(__sparc__)
+#include "processor/stackwalker_sparc.h"
+using google_breakpad::StackwalkerSPARC;
+#endif  // __i386__ || __ppc__ || __sparc__
+#define RECURSION_DEPTH 100
+// A simple MemoryRegion subclass that provides direct access to this
+// process' memory space by pointer.
+class SelfMemoryRegion : public MemoryRegion {
+public:
+virtual uint64_t GetBase() { return 0; }
+virtual uint32_t GetSize() { return 0xffffffff; }
+bool GetMemoryAtAddress(uint64_t address, uint8_t*  value) {
+return GetMemoryAtAddressInternal(address, value); }
+bool GetMemoryAtAddress(uint64_t address, uint16_t* value) {
+return GetMemoryAtAddressInternal(address, value); }
+bool GetMemoryAtAddress(uint64_t address, uint32_t* value) {
+return GetMemoryAtAddressInternal(address, value); }
+bool GetMemoryAtAddress(uint64_t address, uint64_t* value) {
+return GetMemoryAtAddressInternal(address, value); }
+private:
+template<typename T> bool GetMemoryAtAddressInternal(uint64_t address,
+T*        value) {
+// Without knowing what addresses are actually mapped, just assume that
+// everything low is not mapped.  This helps the stackwalker catch the
+// end of a stack when it tries to dereference a null or low pointer
+// in an attempt to find the caller frame.  Other unmapped accesses will
+// cause the program to crash, but that would properly be a test failure.
+if (address < 0x100)
+return false;
+uint8_t* memory = 0;
+*value = *reinterpret_cast<const T*>(&memory[address]);
+return true;
+}
+};
+#if defined(__GNUC__)
+#if defined(__i386__)
+// GetEBP returns the current value of the %ebp register.  Because it's
+// implemented as a function, %ebp itself contains GetEBP's frame pointer
+// and not the caller's frame pointer.  Dereference %ebp to obtain the
+// caller's frame pointer, which the compiler-generated preamble stored
+// on the stack (provided frame pointers are not being omitted.)  Because
+// this function depends on the compiler-generated preamble, inlining is
+// disabled.
+static uint32_t GetEBP() __attribute__((noinline));
+static uint32_t GetEBP() {
+uint32_t ebp;
+__asm__ __volatile__(
+"movl (%%ebp), %0"
+: "=a" (ebp)
+);
+return ebp;
+}
+// The caller's %esp is 8 higher than the value of %ebp in this function,
+// assuming that it's not inlined and that the standard prolog is used.
+// The CALL instruction places a 4-byte return address on the stack above
+// the caller's %esp, and this function's prolog will save the caller's %ebp
+// on the stack as well, for another 4 bytes, before storing %esp in %ebp.
+static uint32_t GetESP() __attribute__((noinline));
+static uint32_t GetESP() {
+uint32_t ebp;
+__asm__ __volatile__(
+"movl %%ebp, %0"
+: "=a" (ebp)
+);
+return ebp + 8;
+}
+// GetEIP returns the instruction pointer identifying the next instruction
+// to execute after GetEIP returns.  It obtains this information from the
+// stack, where it was placed by the call instruction that called GetEIP.
+// This function depends on frame pointers not being omitted.  It is possible
+// to write a pure asm version of this routine that has no compiler-generated
+// preamble and uses %esp instead of %ebp; that would function in the
+// absence of frame pointers.  However, the simpler approach is used here
+// because GetEBP and stackwalking necessarily depends on access to frame
+// pointers.  Because this function depends on a call instruction and the
+// compiler-generated preamble, inlining is disabled.
+static uint32_t GetEIP() __attribute__((noinline));
+static uint32_t GetEIP() {
+uint32_t eip;
+__asm__ __volatile__(
+"movl 4(%%ebp), %0"
+: "=a" (eip)
+);
+return eip;
+}
+#elif defined(__ppc__)
+// GetSP returns the current value of the %r1 register, which by convention,
+// is the stack pointer on ppc.  Because it's implemented as a function,
+// %r1 itself contains GetSP's own stack pointer and not the caller's stack
+// pointer.  Dereference %r1 to obtain the caller's stack pointer, which the
+// compiler-generated prolog stored on the stack.  Because this function
+// depends on the compiler-generated prolog, inlining is disabled.
+static uint32_t GetSP() __attribute__((noinline));
+static uint32_t GetSP() {
+uint32_t sp;
+__asm__ __volatile__(
+"lwz %0, 0(r1)"
+: "=r" (sp)
+);
+return sp;
+}
+// GetPC returns the program counter identifying the next instruction to
+// execute after GetPC returns.  It obtains this information from the
+// link register, where it was placed by the branch instruction that called
+// GetPC.  Because this function depends on the caller's use of a branch
+// instruction, inlining is disabled.
+static uint32_t GetPC() __attribute__((noinline));
+static uint32_t GetPC() {
+uint32_t lr;
+__asm__ __volatile__(
+"mflr %0"
+: "=r" (lr)
+);
+return lr;
+}
+#elif defined(__sparc__)
+// GetSP returns the current value of the %sp/%o6/%g_r[14] register, which
+// by convention, is the stack pointer on sparc.  Because it's implemented
+// as a function, %sp itself contains GetSP's own stack pointer and not
+// the caller's stack pointer.  Dereference  to obtain the caller's stack
+// pointer, which the compiler-generated prolog stored on the stack.
+// Because this function depends on the compiler-generated prolog, inlining
+// is disabled.
+static uint32_t GetSP() __attribute__((noinline));
+static uint32_t GetSP() {
+uint32_t sp;
+__asm__ __volatile__(
+"mov %%fp, %0"
+: "=r" (sp)
+);
+return sp;
+}
+// GetFP returns the current value of the %fp register.  Because it's
+// implemented as a function, %fp itself contains GetFP's frame pointer
+// and not the caller's frame pointer.  Dereference %fp to obtain the
+// caller's frame pointer, which the compiler-generated preamble stored
+// on the stack (provided frame pointers are not being omitted.)  Because
+// this function depends on the compiler-generated preamble, inlining is
+// disabled.
+static uint32_t GetFP() __attribute__((noinline));
+static uint32_t GetFP() {
+uint32_t fp;
+__asm__ __volatile__(
+"ld [%%fp+56], %0"
+: "=r" (fp)
+);
+return fp;
+}
+// GetPC returns the program counter identifying the next instruction to
+// execute after GetPC returns.  It obtains this information from the
+// link register, where it was placed by the branch instruction that called
+// GetPC.  Because this function depends on the caller's use of a branch
+// instruction, inlining is disabled.
+static uint32_t GetPC() __attribute__((noinline));
+static uint32_t GetPC() {
+uint32_t pc;
+__asm__ __volatile__(
+"mov %%i7, %0"
+: "=r" (pc)
+);
+return pc + 8;
+}
+#endif  // __i386__ || __ppc__ || __sparc__
+#elif defined(__SUNPRO_CC)
+#if defined(__i386__)
+extern "C" {
+extern uint32_t GetEIP();
+extern uint32_t GetEBP();
+extern uint32_t GetESP();
+}
+#elif defined(__sparc__)
+extern "C" {
+extern uint32_t GetPC();
+extern uint32_t GetFP();
+extern uint32_t GetSP();
+}
+#endif // __i386__ || __sparc__
+#endif // __GNUC__ || __SUNPRO_CC
+// CountCallerFrames returns the number of stack frames beneath the function
+// that called CountCallerFrames.  Because this function's return value
+// is dependent on the size of the stack beneath it, inlining is disabled,
+// and any function that calls this should not be inlined either.
+#if defined(__GNUC__)
+static unsigned int CountCallerFrames() __attribute__((noinline));
+#elif defined(__SUNPRO_CC)
+static unsigned int CountCallerFrames();
+#endif
+static unsigned int CountCallerFrames() {
+SelfMemoryRegion memory;
+BasicSourceLineResolver resolver;
+#if defined(__i386__)
+MDRawContextX86 context = MDRawContextX86();
+context.eip = GetEIP();
+context.ebp = GetEBP();
+context.esp = GetESP();
+StackwalkerX86 stackwalker = StackwalkerX86(NULL, &context, &memory, NULL,
+NULL, &resolver);
+#elif defined(__ppc__)
+MDRawContextPPC context = MDRawContextPPC();
+context.srr0 = GetPC();
+context.gpr[1] = GetSP();
+StackwalkerPPC stackwalker = StackwalkerPPC(NULL, &context, &memory, NULL,
+NULL, &resolver);
+#elif defined(__sparc__)
+MDRawContextSPARC context = MDRawContextSPARC();
+context.pc = GetPC();
+context.g_r[14] = GetSP();
+context.g_r[30] = GetFP();
+StackwalkerSPARC stackwalker = StackwalkerSPARC(NULL, &context, &memory,
+NULL, NULL, &resolver);
+#endif  // __i386__ || __ppc__ || __sparc__
+CallStack stack;
+vector<const CodeModule*> modules_without_symbols;
+stackwalker.Walk(&stack, &modules_without_symbols);
+#ifdef PRINT_STACKS
+printf("\n");
+for (unsigned int frame_index = 0;
+frame_index < stack.frames()->size();
+++frame_index) {
+StackFrame *frame = stack.frames()->at(frame_index);
+printf("frame %-3d  instruction = 0x%08" PRIx64,
+frame_index, frame->instruction);
+#if defined(__i386__)
+StackFrameX86 *frame_x86 = reinterpret_cast<StackFrameX86*>(frame);
+printf("  esp = 0x%08x  ebp = 0x%08x\n",
+frame_x86->context.esp, frame_x86->context.ebp);
+#elif defined(__ppc__)
+StackFramePPC *frame_ppc = reinterpret_cast<StackFramePPC*>(frame);
+printf("  gpr[1] = 0x%08x\n", frame_ppc->context.gpr[1]);
+#elif defined(__sparc__)
+StackFrameSPARC *frame_sparc = reinterpret_cast<StackFrameSPARC*>(frame);
+printf("  sp = 0x%08x  fp = 0x%08x\n",
+frame_sparc->context.g_r[14], frame_sparc->context.g_r[30]);
+#endif  // __i386__ || __ppc__ || __sparc__
+}
+#endif  // PRINT_STACKS
+// Subtract 1 because the caller wants the number of frames beneath
+// itself.  Because the caller called us, subract two for our frame and its
+// frame, which are included in stack.size().
+return stack.frames()->size() - 2;
+}
+// Recursor verifies that the number stack frames beneath itself is one more
+// than the number of stack frames beneath its parent.  When depth frames
+// have been reached, Recursor stops checking and returns success.  If the
+// frame count check fails at any depth, Recursor will stop and return false.
+// Because this calls CountCallerFrames, inlining is disabled.
+#if defined(__GNUC__)
+static bool Recursor(unsigned int depth, unsigned int parent_callers)
+__attribute__((noinline));
+#elif defined(__SUNPRO_CC)
+static bool Recursor(unsigned int depth, unsigned int parent_callers);
+#endif
+static bool Recursor(unsigned int depth, unsigned int parent_callers) {
+unsigned int callers = CountCallerFrames();
+if (callers != parent_callers + 1)
+return false;
+if (depth)
+return Recursor(depth - 1, callers);
+// depth == 0
+return true;
+}
+// Because this calls CountCallerFrames, inlining is disabled - but because
+// it's main (and nobody calls it other than the entry point), it wouldn't
+// be inlined anyway.
+#if defined(__GNUC__)
+int main(int argc, char** argv) __attribute__((noinline));
+#elif defined(__SUNPRO_CC)
+int main(int argc, char** argv);
+#endif
+int main(int argc, char** argv) {
+BPLOG_INIT(&argc, &argv);
+return Recursor(RECURSION_DEPTH, CountCallerFrames()) ? 0 : 1;
+}
+#else
+// Not i386 or ppc or sparc?  We can only test stacks we know how to walk.
+int main(int argc, char **argv) {
+BPLOG_INIT(&argc, &argv);
+// "make check" interprets an exit status of 77 to mean that the test is
+// not supported.
+BPLOG(ERROR) << "Selftest not supported here";
+return 77;
+}
+#endif  // (__GNUC__ || __SUNPRO_CC) && (__i386__ || __ppc__ || __sparc__)

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