michael@0: // Copyright (c) 2006, Google Inc.
michael@0: // All rights reserved.
michael@0: //
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: // notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: // copyright notice, this list of conditions and the following disclaimer
michael@0: // in the documentation and/or other materials provided with the
michael@0: // distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: // contributors may be used to endorse or promote products derived from
michael@0: // this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: // stackwalker_selftest.cc: Tests StackwalkerX86 or StackwalkerPPC using the
michael@0: // running process' stack as test data, if running on an x86 or ppc and
michael@0: // compiled with gcc.  This test is not enabled in the "make check" suite
michael@0: // by default, because certain optimizations interfere with its proper
michael@0: // operation.  To turn it on, configure with --enable-selftest.
michael@0: //
michael@0: // Optimizations that cause problems:
michael@0: //  - stack frame reuse.  The Recursor function here calls itself with
michael@0: //    |return Recursor|.  When the caller's frame is reused, it will cause
michael@0: //    CountCallerFrames to correctly return the same number of frames
michael@0: //    in both the caller and callee.  This is considered an unexpected
michael@0: //    condition in the test, which expects a callee to have one more
michael@0: //    caller frame in the stack than its caller.
michael@0: //  - frame pointer omission.  Even with a stackwalker that understands
michael@0: //    this optimization, the code to harness debug information currently
michael@0: //    only exists to retrieve it from minidumps, not the current process.
michael@0: //
michael@0: // This test can also serve as a developmental and debugging aid if
michael@0: // PRINT_STACKS is defined.
michael@0: //
michael@0: // Author: Mark Mentovai
michael@0: 
michael@0: #include "processor/logging.h"
michael@0: 
michael@0: #if defined(__i386) && !defined(__i386__)
michael@0: #define __i386__
michael@0: #endif
michael@0: #if defined(__sparc) && !defined(__sparc__)
michael@0: #define __sparc__
michael@0: #endif
michael@0:  
michael@0: #if (defined(__SUNPRO_CC) || defined(__GNUC__)) && \
michael@0:     (defined(__i386__) || defined(__ppc__) || defined(__sparc__))
michael@0: 
michael@0: 
michael@0: #include <stdio.h>
michael@0: 
michael@0: #include "common/scoped_ptr.h"
michael@0: #include "google_breakpad/common/breakpad_types.h"
michael@0: #include "google_breakpad/common/minidump_format.h"
michael@0: #include "google_breakpad/processor/basic_source_line_resolver.h"
michael@0: #include "google_breakpad/processor/call_stack.h"
michael@0: #include "google_breakpad/processor/code_module.h"
michael@0: #include "google_breakpad/processor/memory_region.h"
michael@0: #include "google_breakpad/processor/stack_frame.h"
michael@0: #include "google_breakpad/processor/stack_frame_cpu.h"
michael@0: 
michael@0: using google_breakpad::BasicSourceLineResolver;
michael@0: using google_breakpad::CallStack;
michael@0: using google_breakpad::CodeModule;
michael@0: using google_breakpad::MemoryRegion;
michael@0: using google_breakpad::scoped_ptr;
michael@0: using google_breakpad::StackFrame;
michael@0: using google_breakpad::StackFramePPC;
michael@0: using google_breakpad::StackFrameX86;
michael@0: using google_breakpad::StackFrameSPARC;
michael@0: 
michael@0: #if defined(__i386__)
michael@0: #include "processor/stackwalker_x86.h"
michael@0: using google_breakpad::StackwalkerX86;
michael@0: #elif defined(__ppc__)
michael@0: #include "processor/stackwalker_ppc.h"
michael@0: using google_breakpad::StackwalkerPPC;
michael@0: #elif defined(__sparc__)
michael@0: #include "processor/stackwalker_sparc.h"
michael@0: using google_breakpad::StackwalkerSPARC;
michael@0: #endif  // __i386__ || __ppc__ || __sparc__
michael@0: 
michael@0: #define RECURSION_DEPTH 100
michael@0: 
michael@0: 
michael@0: // A simple MemoryRegion subclass that provides direct access to this
michael@0: // process' memory space by pointer.
michael@0: class SelfMemoryRegion : public MemoryRegion {
michael@0:  public:
michael@0:   virtual uint64_t GetBase() { return 0; }
michael@0:   virtual uint32_t GetSize() { return 0xffffffff; }
michael@0: 
michael@0:   bool GetMemoryAtAddress(uint64_t address, uint8_t*  value) {
michael@0:       return GetMemoryAtAddressInternal(address, value); }
michael@0:   bool GetMemoryAtAddress(uint64_t address, uint16_t* value) {
michael@0:       return GetMemoryAtAddressInternal(address, value); }
michael@0:   bool GetMemoryAtAddress(uint64_t address, uint32_t* value) {
michael@0:       return GetMemoryAtAddressInternal(address, value); }
michael@0:   bool GetMemoryAtAddress(uint64_t address, uint64_t* value) {
michael@0:       return GetMemoryAtAddressInternal(address, value); }
michael@0: 
michael@0:  private:
michael@0:   template<typename T> bool GetMemoryAtAddressInternal(uint64_t address,
michael@0:                                                        T*        value) {
michael@0:     // Without knowing what addresses are actually mapped, just assume that
michael@0:     // everything low is not mapped.  This helps the stackwalker catch the
michael@0:     // end of a stack when it tries to dereference a null or low pointer
michael@0:     // in an attempt to find the caller frame.  Other unmapped accesses will
michael@0:     // cause the program to crash, but that would properly be a test failure.
michael@0:     if (address < 0x100)
michael@0:       return false;
michael@0: 
michael@0:     uint8_t* memory = 0;
michael@0:     *value = *reinterpret_cast<const T*>(&memory[address]);
michael@0:     return true;
michael@0:   }
michael@0: };
michael@0: 
michael@0: 
michael@0: #if defined(__GNUC__)
michael@0: 
michael@0: 
michael@0: #if defined(__i386__)
michael@0: 
michael@0: // GetEBP returns the current value of the %ebp register.  Because it's
michael@0: // implemented as a function, %ebp itself contains GetEBP's frame pointer
michael@0: // and not the caller's frame pointer.  Dereference %ebp to obtain the
michael@0: // caller's frame pointer, which the compiler-generated preamble stored
michael@0: // on the stack (provided frame pointers are not being omitted.)  Because
michael@0: // this function depends on the compiler-generated preamble, inlining is
michael@0: // disabled.
michael@0: static uint32_t GetEBP() __attribute__((noinline));
michael@0: static uint32_t GetEBP() {
michael@0:   uint32_t ebp;
michael@0:   __asm__ __volatile__(
michael@0:     "movl (%%ebp), %0"
michael@0:     : "=a" (ebp)
michael@0:   );
michael@0:   return ebp;
michael@0: }
michael@0: 
michael@0: 
michael@0: // The caller's %esp is 8 higher than the value of %ebp in this function,
michael@0: // assuming that it's not inlined and that the standard prolog is used.
michael@0: // The CALL instruction places a 4-byte return address on the stack above
michael@0: // the caller's %esp, and this function's prolog will save the caller's %ebp
michael@0: // on the stack as well, for another 4 bytes, before storing %esp in %ebp.
michael@0: static uint32_t GetESP() __attribute__((noinline));
michael@0: static uint32_t GetESP() {
michael@0:   uint32_t ebp;
michael@0:   __asm__ __volatile__(
michael@0:     "movl %%ebp, %0"
michael@0:     : "=a" (ebp)
michael@0:   );
michael@0:   return ebp + 8;
michael@0: }
michael@0: 
michael@0: 
michael@0: // GetEIP returns the instruction pointer identifying the next instruction
michael@0: // to execute after GetEIP returns.  It obtains this information from the
michael@0: // stack, where it was placed by the call instruction that called GetEIP.
michael@0: // This function depends on frame pointers not being omitted.  It is possible
michael@0: // to write a pure asm version of this routine that has no compiler-generated
michael@0: // preamble and uses %esp instead of %ebp; that would function in the
michael@0: // absence of frame pointers.  However, the simpler approach is used here
michael@0: // because GetEBP and stackwalking necessarily depends on access to frame
michael@0: // pointers.  Because this function depends on a call instruction and the
michael@0: // compiler-generated preamble, inlining is disabled.
michael@0: static uint32_t GetEIP() __attribute__((noinline));
michael@0: static uint32_t GetEIP() {
michael@0:   uint32_t eip;
michael@0:   __asm__ __volatile__(
michael@0:     "movl 4(%%ebp), %0"
michael@0:     : "=a" (eip)
michael@0:   );
michael@0:   return eip;
michael@0: }
michael@0: 
michael@0: 
michael@0: #elif defined(__ppc__)
michael@0: 
michael@0: 
michael@0: // GetSP returns the current value of the %r1 register, which by convention,
michael@0: // is the stack pointer on ppc.  Because it's implemented as a function,
michael@0: // %r1 itself contains GetSP's own stack pointer and not the caller's stack
michael@0: // pointer.  Dereference %r1 to obtain the caller's stack pointer, which the
michael@0: // compiler-generated prolog stored on the stack.  Because this function
michael@0: // depends on the compiler-generated prolog, inlining is disabled.
michael@0: static uint32_t GetSP() __attribute__((noinline));
michael@0: static uint32_t GetSP() {
michael@0:   uint32_t sp;
michael@0:   __asm__ __volatile__(
michael@0:     "lwz %0, 0(r1)"
michael@0:     : "=r" (sp)
michael@0:   );
michael@0:   return sp;
michael@0: }
michael@0: 
michael@0: 
michael@0: // GetPC returns the program counter identifying the next instruction to
michael@0: // execute after GetPC returns.  It obtains this information from the
michael@0: // link register, where it was placed by the branch instruction that called
michael@0: // GetPC.  Because this function depends on the caller's use of a branch
michael@0: // instruction, inlining is disabled.
michael@0: static uint32_t GetPC() __attribute__((noinline));
michael@0: static uint32_t GetPC() {
michael@0:   uint32_t lr;
michael@0:   __asm__ __volatile__(
michael@0:     "mflr %0"
michael@0:     : "=r" (lr)
michael@0:   );
michael@0:   return lr;
michael@0: }
michael@0: 
michael@0: 
michael@0: #elif defined(__sparc__)
michael@0: 
michael@0: 
michael@0: // GetSP returns the current value of the %sp/%o6/%g_r[14] register, which 
michael@0: // by convention, is the stack pointer on sparc.  Because it's implemented
michael@0: // as a function, %sp itself contains GetSP's own stack pointer and not 
michael@0: // the caller's stack pointer.  Dereference  to obtain the caller's stack 
michael@0: // pointer, which the compiler-generated prolog stored on the stack.
michael@0: // Because this function depends on the compiler-generated prolog, inlining
michael@0: // is disabled.
michael@0: static uint32_t GetSP() __attribute__((noinline));
michael@0: static uint32_t GetSP() {
michael@0:   uint32_t sp;
michael@0:   __asm__ __volatile__(
michael@0:     "mov %%fp, %0"
michael@0:     : "=r" (sp)
michael@0:   );
michael@0:   return sp;
michael@0: }
michael@0: 
michael@0: // GetFP returns the current value of the %fp register.  Because it's
michael@0: // implemented as a function, %fp itself contains GetFP's frame pointer
michael@0: // and not the caller's frame pointer.  Dereference %fp to obtain the
michael@0: // caller's frame pointer, which the compiler-generated preamble stored
michael@0: // on the stack (provided frame pointers are not being omitted.)  Because
michael@0: // this function depends on the compiler-generated preamble, inlining is
michael@0: // disabled.
michael@0: static uint32_t GetFP() __attribute__((noinline));
michael@0: static uint32_t GetFP() {
michael@0:   uint32_t fp;
michael@0:   __asm__ __volatile__(
michael@0:     "ld [%%fp+56], %0"
michael@0:     : "=r" (fp)
michael@0:   );
michael@0:   return fp;
michael@0: }
michael@0: 
michael@0: // GetPC returns the program counter identifying the next instruction to
michael@0: // execute after GetPC returns.  It obtains this information from the
michael@0: // link register, where it was placed by the branch instruction that called
michael@0: // GetPC.  Because this function depends on the caller's use of a branch
michael@0: // instruction, inlining is disabled.
michael@0: static uint32_t GetPC() __attribute__((noinline));
michael@0: static uint32_t GetPC() {
michael@0:   uint32_t pc;
michael@0:   __asm__ __volatile__(
michael@0:     "mov %%i7, %0"
michael@0:     : "=r" (pc)
michael@0:   );
michael@0:   return pc + 8;
michael@0: }
michael@0: 
michael@0: #endif  // __i386__ || __ppc__ || __sparc__
michael@0: 
michael@0: #elif defined(__SUNPRO_CC)
michael@0: 
michael@0: #if defined(__i386__)
michael@0: extern "C" {
michael@0: extern uint32_t GetEIP();
michael@0: extern uint32_t GetEBP();
michael@0: extern uint32_t GetESP();
michael@0: }
michael@0: #elif defined(__sparc__)
michael@0: extern "C" {
michael@0: extern uint32_t GetPC();
michael@0: extern uint32_t GetFP();
michael@0: extern uint32_t GetSP();
michael@0: }
michael@0: #endif // __i386__ || __sparc__
michael@0: 
michael@0: #endif // __GNUC__ || __SUNPRO_CC
michael@0: 
michael@0: // CountCallerFrames returns the number of stack frames beneath the function
michael@0: // that called CountCallerFrames.  Because this function's return value
michael@0: // is dependent on the size of the stack beneath it, inlining is disabled,
michael@0: // and any function that calls this should not be inlined either.
michael@0: #if defined(__GNUC__)
michael@0: static unsigned int CountCallerFrames() __attribute__((noinline));
michael@0: #elif defined(__SUNPRO_CC)
michael@0: static unsigned int CountCallerFrames();
michael@0: #endif
michael@0: static unsigned int CountCallerFrames() {
michael@0:   SelfMemoryRegion memory;
michael@0:   BasicSourceLineResolver resolver;
michael@0: 
michael@0: #if defined(__i386__)
michael@0:   MDRawContextX86 context = MDRawContextX86();
michael@0:   context.eip = GetEIP();
michael@0:   context.ebp = GetEBP();
michael@0:   context.esp = GetESP();
michael@0: 
michael@0:   StackwalkerX86 stackwalker = StackwalkerX86(NULL, &context, &memory, NULL,
michael@0:                                               NULL, &resolver);
michael@0: #elif defined(__ppc__)
michael@0:   MDRawContextPPC context = MDRawContextPPC();
michael@0:   context.srr0 = GetPC();
michael@0:   context.gpr[1] = GetSP();
michael@0: 
michael@0:   StackwalkerPPC stackwalker = StackwalkerPPC(NULL, &context, &memory, NULL,
michael@0:                                               NULL, &resolver);
michael@0: #elif defined(__sparc__)
michael@0:   MDRawContextSPARC context = MDRawContextSPARC();
michael@0:   context.pc = GetPC();
michael@0:   context.g_r[14] = GetSP();
michael@0:   context.g_r[30] = GetFP();
michael@0: 
michael@0:   StackwalkerSPARC stackwalker = StackwalkerSPARC(NULL, &context, &memory,
michael@0:                                                   NULL, NULL, &resolver);
michael@0: #endif  // __i386__ || __ppc__ || __sparc__
michael@0: 
michael@0:   CallStack stack;
michael@0:   vector<const CodeModule*> modules_without_symbols;
michael@0:   stackwalker.Walk(&stack, &modules_without_symbols);
michael@0: 
michael@0: #ifdef PRINT_STACKS
michael@0:   printf("\n");
michael@0:   for (unsigned int frame_index = 0;
michael@0:       frame_index < stack.frames()->size();
michael@0:       ++frame_index) {
michael@0:     StackFrame *frame = stack.frames()->at(frame_index);
michael@0:     printf("frame %-3d  instruction = 0x%08" PRIx64,
michael@0:            frame_index, frame->instruction);
michael@0: #if defined(__i386__)
michael@0:     StackFrameX86 *frame_x86 = reinterpret_cast<StackFrameX86*>(frame);
michael@0:     printf("  esp = 0x%08x  ebp = 0x%08x\n",
michael@0:            frame_x86->context.esp, frame_x86->context.ebp);
michael@0: #elif defined(__ppc__)
michael@0:     StackFramePPC *frame_ppc = reinterpret_cast<StackFramePPC*>(frame);
michael@0:     printf("  gpr[1] = 0x%08x\n", frame_ppc->context.gpr[1]);
michael@0: #elif defined(__sparc__)
michael@0:     StackFrameSPARC *frame_sparc = reinterpret_cast<StackFrameSPARC*>(frame);
michael@0:     printf("  sp = 0x%08x  fp = 0x%08x\n",
michael@0:            frame_sparc->context.g_r[14], frame_sparc->context.g_r[30]);
michael@0: #endif  // __i386__ || __ppc__ || __sparc__
michael@0:   }
michael@0: #endif  // PRINT_STACKS
michael@0: 
michael@0:   // Subtract 1 because the caller wants the number of frames beneath
michael@0:   // itself.  Because the caller called us, subract two for our frame and its
michael@0:   // frame, which are included in stack.size().
michael@0:   return stack.frames()->size() - 2;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Recursor verifies that the number stack frames beneath itself is one more
michael@0: // than the number of stack frames beneath its parent.  When depth frames
michael@0: // have been reached, Recursor stops checking and returns success.  If the
michael@0: // frame count check fails at any depth, Recursor will stop and return false.
michael@0: // Because this calls CountCallerFrames, inlining is disabled.
michael@0: #if defined(__GNUC__)
michael@0: static bool Recursor(unsigned int depth, unsigned int parent_callers)
michael@0:     __attribute__((noinline));
michael@0: #elif defined(__SUNPRO_CC)
michael@0: static bool Recursor(unsigned int depth, unsigned int parent_callers);
michael@0: #endif
michael@0: static bool Recursor(unsigned int depth, unsigned int parent_callers) {
michael@0:   unsigned int callers = CountCallerFrames();
michael@0:   if (callers != parent_callers + 1)
michael@0:     return false;
michael@0: 
michael@0:   if (depth)
michael@0:     return Recursor(depth - 1, callers);
michael@0: 
michael@0:   // depth == 0
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: 
michael@0: // Because this calls CountCallerFrames, inlining is disabled - but because
michael@0: // it's main (and nobody calls it other than the entry point), it wouldn't
michael@0: // be inlined anyway.
michael@0: #if defined(__GNUC__)
michael@0: int main(int argc, char** argv) __attribute__((noinline));
michael@0: #elif defined(__SUNPRO_CC)
michael@0: int main(int argc, char** argv);
michael@0: #endif
michael@0: int main(int argc, char** argv) {
michael@0:   BPLOG_INIT(&argc, &argv);
michael@0: 
michael@0:   return Recursor(RECURSION_DEPTH, CountCallerFrames()) ? 0 : 1;
michael@0: }
michael@0: 
michael@0: 
michael@0: #else
michael@0: // Not i386 or ppc or sparc?  We can only test stacks we know how to walk.
michael@0: 
michael@0: 
michael@0: int main(int argc, char **argv) {
michael@0:   BPLOG_INIT(&argc, &argv);
michael@0: 
michael@0:   // "make check" interprets an exit status of 77 to mean that the test is
michael@0:   // not supported.
michael@0:   BPLOG(ERROR) << "Selftest not supported here";
michael@0:   return 77;
michael@0: }
michael@0: 
michael@0: 
michael@0: #endif  // (__GNUC__ || __SUNPRO_CC) && (__i386__ || __ppc__ || __sparc__)