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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 <assert.h>
#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() const { return 0; }
virtual uint32_t GetSize() const { return 0xffffffff; }
bool GetMemoryAtAddress(uint64_t address, uint8_t* value) const {
return GetMemoryAtAddressInternal(address, value); }
bool GetMemoryAtAddress(uint64_t address, uint16_t* value) const {
return GetMemoryAtAddressInternal(address, value); }
bool GetMemoryAtAddress(uint64_t address, uint32_t* value) const {
return GetMemoryAtAddressInternal(address, value); }
bool GetMemoryAtAddress(uint64_t address, uint64_t* value) const {
return GetMemoryAtAddressInternal(address, value); }
void Print() const {
assert(false);
}
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__)