1 // Copyright (c) 2006, Google Inc.
2 // All rights reserved.
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
14 // * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 // stackwalker_selftest.cc: Tests StackwalkerX86 or StackwalkerPPC using the
31 // running process' stack as test data, if running on an x86 or ppc and
32 // compiled with gcc. This test is not enabled in the "make check" suite
33 // by default, because certain optimizations interfere with its proper
34 // operation. To turn it on, configure with --enable-selftest.
36 // Optimizations that cause problems:
37 // - stack frame reuse. The Recursor function here calls itself with
38 // |return Recursor|. When the caller's frame is reused, it will cause
39 // CountCallerFrames to correctly return the same number of frames
40 // in both the caller and callee. This is considered an unexpected
41 // condition in the test, which expects a callee to have one more
42 // caller frame in the stack than its caller.
43 // - frame pointer omission. Even with a stackwalker that understands
44 // this optimization, the code to harness debug information currently
45 // only exists to retrieve it from minidumps, not the current process.
47 // This test can also serve as a developmental and debugging aid if
48 // PRINT_STACKS is defined.
50 // Author: Mark Mentovai
52 #include "processor/logging.h"
54 #if defined(__i386) && !defined(__i386__)
57 #if defined(__sparc) && !defined(__sparc__)
61 #if (defined(__SUNPRO_CC) || defined(__GNUC__)) && \
62 (defined(__i386__) || defined(__ppc__) || defined(__sparc__))
67 #include "common/scoped_ptr.h"
68 #include "google_breakpad/common/breakpad_types.h"
69 #include "google_breakpad/common/minidump_format.h"
70 #include "google_breakpad/processor/basic_source_line_resolver.h"
71 #include "google_breakpad/processor/call_stack.h"
72 #include "google_breakpad/processor/code_module.h"
73 #include "google_breakpad/processor/memory_region.h"
74 #include "google_breakpad/processor/stack_frame.h"
75 #include "google_breakpad/processor/stack_frame_cpu.h"
77 using google_breakpad::BasicSourceLineResolver;
78 using google_breakpad::CallStack;
79 using google_breakpad::CodeModule;
80 using google_breakpad::MemoryRegion;
81 using google_breakpad::scoped_ptr;
82 using google_breakpad::StackFrame;
83 using google_breakpad::StackFramePPC;
84 using google_breakpad::StackFrameX86;
85 using google_breakpad::StackFrameSPARC;
88 #include "processor/stackwalker_x86.h"
89 using google_breakpad::StackwalkerX86;
90 #elif defined(__ppc__)
91 #include "processor/stackwalker_ppc.h"
92 using google_breakpad::StackwalkerPPC;
93 #elif defined(__sparc__)
94 #include "processor/stackwalker_sparc.h"
95 using google_breakpad::StackwalkerSPARC;
96 #endif // __i386__ || __ppc__ || __sparc__
98 #define RECURSION_DEPTH 100
101 // A simple MemoryRegion subclass that provides direct access to this
102 // process' memory space by pointer.
103 class SelfMemoryRegion : public MemoryRegion {
105 virtual uint64_t GetBase() { return 0; }
106 virtual uint32_t GetSize() { return 0xffffffff; }
108 bool GetMemoryAtAddress(uint64_t address, uint8_t* value) {
109 return GetMemoryAtAddressInternal(address, value); }
110 bool GetMemoryAtAddress(uint64_t address, uint16_t* value) {
111 return GetMemoryAtAddressInternal(address, value); }
112 bool GetMemoryAtAddress(uint64_t address, uint32_t* value) {
113 return GetMemoryAtAddressInternal(address, value); }
114 bool GetMemoryAtAddress(uint64_t address, uint64_t* value) {
115 return GetMemoryAtAddressInternal(address, value); }
118 template<typename T> bool GetMemoryAtAddressInternal(uint64_t address,
120 // Without knowing what addresses are actually mapped, just assume that
121 // everything low is not mapped. This helps the stackwalker catch the
122 // end of a stack when it tries to dereference a null or low pointer
123 // in an attempt to find the caller frame. Other unmapped accesses will
124 // cause the program to crash, but that would properly be a test failure.
129 *value = *reinterpret_cast<const T*>(&memory[address]);
135 #if defined(__GNUC__)
138 #if defined(__i386__)
140 // GetEBP returns the current value of the %ebp register. Because it's
141 // implemented as a function, %ebp itself contains GetEBP's frame pointer
142 // and not the caller's frame pointer. Dereference %ebp to obtain the
143 // caller's frame pointer, which the compiler-generated preamble stored
144 // on the stack (provided frame pointers are not being omitted.) Because
145 // this function depends on the compiler-generated preamble, inlining is
147 static uint32_t GetEBP() __attribute__((noinline));
148 static uint32_t GetEBP() {
150 __asm__ __volatile__(
158 // The caller's %esp is 8 higher than the value of %ebp in this function,
159 // assuming that it's not inlined and that the standard prolog is used.
160 // The CALL instruction places a 4-byte return address on the stack above
161 // the caller's %esp, and this function's prolog will save the caller's %ebp
162 // on the stack as well, for another 4 bytes, before storing %esp in %ebp.
163 static uint32_t GetESP() __attribute__((noinline));
164 static uint32_t GetESP() {
166 __asm__ __volatile__(
174 // GetEIP returns the instruction pointer identifying the next instruction
175 // to execute after GetEIP returns. It obtains this information from the
176 // stack, where it was placed by the call instruction that called GetEIP.
177 // This function depends on frame pointers not being omitted. It is possible
178 // to write a pure asm version of this routine that has no compiler-generated
179 // preamble and uses %esp instead of %ebp; that would function in the
180 // absence of frame pointers. However, the simpler approach is used here
181 // because GetEBP and stackwalking necessarily depends on access to frame
182 // pointers. Because this function depends on a call instruction and the
183 // compiler-generated preamble, inlining is disabled.
184 static uint32_t GetEIP() __attribute__((noinline));
185 static uint32_t GetEIP() {
187 __asm__ __volatile__(
195 #elif defined(__ppc__)
198 // GetSP returns the current value of the %r1 register, which by convention,
199 // is the stack pointer on ppc. Because it's implemented as a function,
200 // %r1 itself contains GetSP's own stack pointer and not the caller's stack
201 // pointer. Dereference %r1 to obtain the caller's stack pointer, which the
202 // compiler-generated prolog stored on the stack. Because this function
203 // depends on the compiler-generated prolog, inlining is disabled.
204 static uint32_t GetSP() __attribute__((noinline));
205 static uint32_t GetSP() {
207 __asm__ __volatile__(
215 // GetPC returns the program counter identifying the next instruction to
216 // execute after GetPC returns. It obtains this information from the
217 // link register, where it was placed by the branch instruction that called
218 // GetPC. Because this function depends on the caller's use of a branch
219 // instruction, inlining is disabled.
220 static uint32_t GetPC() __attribute__((noinline));
221 static uint32_t GetPC() {
223 __asm__ __volatile__(
231 #elif defined(__sparc__)
234 // GetSP returns the current value of the %sp/%o6/%g_r[14] register, which
235 // by convention, is the stack pointer on sparc. Because it's implemented
236 // as a function, %sp itself contains GetSP's own stack pointer and not
237 // the caller's stack pointer. Dereference to obtain the caller's stack
238 // pointer, which the compiler-generated prolog stored on the stack.
239 // Because this function depends on the compiler-generated prolog, inlining
241 static uint32_t GetSP() __attribute__((noinline));
242 static uint32_t GetSP() {
244 __asm__ __volatile__(
251 // GetFP returns the current value of the %fp register. Because it's
252 // implemented as a function, %fp itself contains GetFP's frame pointer
253 // and not the caller's frame pointer. Dereference %fp to obtain the
254 // caller's frame pointer, which the compiler-generated preamble stored
255 // on the stack (provided frame pointers are not being omitted.) Because
256 // this function depends on the compiler-generated preamble, inlining is
258 static uint32_t GetFP() __attribute__((noinline));
259 static uint32_t GetFP() {
261 __asm__ __volatile__(
268 // GetPC returns the program counter identifying the next instruction to
269 // execute after GetPC returns. It obtains this information from the
270 // link register, where it was placed by the branch instruction that called
271 // GetPC. Because this function depends on the caller's use of a branch
272 // instruction, inlining is disabled.
273 static uint32_t GetPC() __attribute__((noinline));
274 static uint32_t GetPC() {
276 __asm__ __volatile__(
283 #endif // __i386__ || __ppc__ || __sparc__
285 #elif defined(__SUNPRO_CC)
287 #if defined(__i386__)
289 extern uint32_t GetEIP();
290 extern uint32_t GetEBP();
291 extern uint32_t GetESP();
293 #elif defined(__sparc__)
295 extern uint32_t GetPC();
296 extern uint32_t GetFP();
297 extern uint32_t GetSP();
299 #endif // __i386__ || __sparc__
301 #endif // __GNUC__ || __SUNPRO_CC
303 // CountCallerFrames returns the number of stack frames beneath the function
304 // that called CountCallerFrames. Because this function's return value
305 // is dependent on the size of the stack beneath it, inlining is disabled,
306 // and any function that calls this should not be inlined either.
307 #if defined(__GNUC__)
308 static unsigned int CountCallerFrames() __attribute__((noinline));
309 #elif defined(__SUNPRO_CC)
310 static unsigned int CountCallerFrames();
312 static unsigned int CountCallerFrames() {
313 SelfMemoryRegion memory;
314 BasicSourceLineResolver resolver;
316 #if defined(__i386__)
317 MDRawContextX86 context = MDRawContextX86();
318 context.eip = GetEIP();
319 context.ebp = GetEBP();
320 context.esp = GetESP();
322 StackwalkerX86 stackwalker = StackwalkerX86(NULL, &context, &memory, NULL,
324 #elif defined(__ppc__)
325 MDRawContextPPC context = MDRawContextPPC();
326 context.srr0 = GetPC();
327 context.gpr[1] = GetSP();
329 StackwalkerPPC stackwalker = StackwalkerPPC(NULL, &context, &memory, NULL,
331 #elif defined(__sparc__)
332 MDRawContextSPARC context = MDRawContextSPARC();
333 context.pc = GetPC();
334 context.g_r[14] = GetSP();
335 context.g_r[30] = GetFP();
337 StackwalkerSPARC stackwalker = StackwalkerSPARC(NULL, &context, &memory,
338 NULL, NULL, &resolver);
339 #endif // __i386__ || __ppc__ || __sparc__
342 vector<const CodeModule*> modules_without_symbols;
343 stackwalker.Walk(&stack, &modules_without_symbols);
347 for (unsigned int frame_index = 0;
348 frame_index < stack.frames()->size();
350 StackFrame *frame = stack.frames()->at(frame_index);
351 printf("frame %-3d instruction = 0x%08" PRIx64,
352 frame_index, frame->instruction);
353 #if defined(__i386__)
354 StackFrameX86 *frame_x86 = reinterpret_cast<StackFrameX86*>(frame);
355 printf(" esp = 0x%08x ebp = 0x%08x\n",
356 frame_x86->context.esp, frame_x86->context.ebp);
357 #elif defined(__ppc__)
358 StackFramePPC *frame_ppc = reinterpret_cast<StackFramePPC*>(frame);
359 printf(" gpr[1] = 0x%08x\n", frame_ppc->context.gpr[1]);
360 #elif defined(__sparc__)
361 StackFrameSPARC *frame_sparc = reinterpret_cast<StackFrameSPARC*>(frame);
362 printf(" sp = 0x%08x fp = 0x%08x\n",
363 frame_sparc->context.g_r[14], frame_sparc->context.g_r[30]);
364 #endif // __i386__ || __ppc__ || __sparc__
366 #endif // PRINT_STACKS
368 // Subtract 1 because the caller wants the number of frames beneath
369 // itself. Because the caller called us, subract two for our frame and its
370 // frame, which are included in stack.size().
371 return stack.frames()->size() - 2;
375 // Recursor verifies that the number stack frames beneath itself is one more
376 // than the number of stack frames beneath its parent. When depth frames
377 // have been reached, Recursor stops checking and returns success. If the
378 // frame count check fails at any depth, Recursor will stop and return false.
379 // Because this calls CountCallerFrames, inlining is disabled.
380 #if defined(__GNUC__)
381 static bool Recursor(unsigned int depth, unsigned int parent_callers)
382 __attribute__((noinline));
383 #elif defined(__SUNPRO_CC)
384 static bool Recursor(unsigned int depth, unsigned int parent_callers);
386 static bool Recursor(unsigned int depth, unsigned int parent_callers) {
387 unsigned int callers = CountCallerFrames();
388 if (callers != parent_callers + 1)
392 return Recursor(depth - 1, callers);
399 // Because this calls CountCallerFrames, inlining is disabled - but because
400 // it's main (and nobody calls it other than the entry point), it wouldn't
401 // be inlined anyway.
402 #if defined(__GNUC__)
403 int main(int argc, char** argv) __attribute__((noinline));
404 #elif defined(__SUNPRO_CC)
405 int main(int argc, char** argv);
407 int main(int argc, char** argv) {
408 BPLOG_INIT(&argc, &argv);
410 return Recursor(RECURSION_DEPTH, CountCallerFrames()) ? 0 : 1;
415 // Not i386 or ppc or sparc? We can only test stacks we know how to walk.
418 int main(int argc, char **argv) {
419 BPLOG_INIT(&argc, &argv);
421 // "make check" interprets an exit status of 77 to mean that the test is
423 BPLOG(ERROR) << "Selftest not supported here";
428 #endif // (__GNUC__ || __SUNPRO_CC) && (__i386__ || __ppc__ || __sparc__)