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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__)