third_party/tcmalloc/chromium/src/stacktrace_arm-inl.h

   1 // Copyright (c) 2011, Google Inc.
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are
   6 // met:
   7 //
   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
  13 // distribution.
  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.
  17 //
  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.
  29
  30 // ---
  31 // Author: Doug Kwan
  32 // This is inspired by Craig Silverstein's PowerPC stacktrace code.
  33 //
  34
  35 #ifndef BASE_STACKTRACE_ARM_INL_H_
  36 #define BASE_STACKTRACE_ARM_INL_H_
  37 // Note: this file is included into stacktrace.cc more than once.
  38 // Anything that should only be defined once should be here:
  39
  40 #include <stdint.h>   // for uintptr_t
  41 #include "base/basictypes.h"  // for NULL
  42 #include <gperftools/stacktrace.h>
  43
  44 // WARNING:
  45 // This only works if all your code is in either ARM or THUMB mode.  With
  46 // interworking, the frame pointer of the caller can either be in r11 (ARM
  47 // mode) or r7 (THUMB mode).  A callee only saves the frame pointer of its
  48 // mode in a fixed location on its stack frame.  If the caller is a different
  49 // mode, there is no easy way to find the frame pointer.  It can either be
  50 // still in the designated register or saved on stack along with other callee
  51 // saved registers.
  52
  53 // Given a pointer to a stack frame, locate and return the calling
  54 // stackframe, or return NULL if no stackframe can be found. Perform sanity
  55 // checks (the strictness of which is controlled by the boolean parameter
  56 // "STRICT_UNWINDING") to reduce the chance that a bad pointer is returned.
  57 template<bool STRICT_UNWINDING>
  58 static void **NextStackFrame(void **old_sp) {
  59   void **new_sp = (void**) old_sp[-1];
  60
  61   // Check that the transition from frame pointer old_sp to frame
  62   // pointer new_sp isn't clearly bogus
  63   if (STRICT_UNWINDING) {
  64     // With the stack growing downwards, older stack frame must be
  65     // at a greater address that the current one.
  66     if (new_sp <= old_sp) return NULL;
  67     // Assume stack frames larger than 100,000 bytes are bogus.
  68     if ((uintptr_t)new_sp - (uintptr_t)old_sp > 100000) return NULL;
  69   } else {
  70     // In the non-strict mode, allow discontiguous stack frames.
  71     // (alternate-signal-stacks for example).
  72     if (new_sp == old_sp) return NULL;
  73     // And allow frames upto about 1MB.
  74     if ((new_sp > old_sp)
  75         && ((uintptr_t)new_sp - (uintptr_t)old_sp > 1000000)) return NULL;
  76   }
  77   if ((uintptr_t)new_sp & (sizeof(void *) - 1)) return NULL;
  78   return new_sp;
  79 }
  80
  81 // This ensures that GetStackTrace stes up the Link Register properly.
  82 #ifdef __GNUC__
  83 void StacktraceArmDummyFunction() __attribute__((noinline));
  84 void StacktraceArmDummyFunction() { __asm__ volatile(""); }
  85 #else
  86 # error StacktraceArmDummyFunction() needs to be ported to this platform.
  87 #endif
  88 #endif  // BASE_STACKTRACE_ARM_INL_H_
  89
  90 // Note: this part of the file is included several times.
  91 // Do not put globals below.
  92
  93 // The following 4 functions are generated from the code below:
  94 //   GetStack{Trace,Frames}()
  95 //   GetStack{Trace,Frames}WithContext()
  96 //
  97 // These functions take the following args:
  98 //   void** result: the stack-trace, as an array
  99 //   int* sizes: the size of each stack frame, as an array
 100 //               (GetStackFrames* only)
 101 //   int max_depth: the size of the result (and sizes) array(s)
 102 //   int skip_count: how many stack pointers to skip before storing in result
 103 //   void* ucp: a ucontext_t* (GetStack{Trace,Frames}WithContext only)
 104 int GET_STACK_TRACE_OR_FRAMES {
 105 #ifdef __GNUC__
 106   void **sp = reinterpret_cast<void**>(__builtin_frame_address(0));
 107 #else
 108 # error reading stack point not yet supported on this platform.
 109 #endif
 110
 111   // On ARM, the return address is stored in the link register (r14).
 112   // This is not saved on the stack frame of a leaf function.  To
 113   // simplify code that reads return addresses, we call a dummy
 114   // function so that the return address of this function is also
 115   // stored in the stack frame.  This works at least for gcc.
 116   StacktraceArmDummyFunction();
 117
 118   int n = 0;
 119   while (sp && n < max_depth) {
 120     // The GetStackFrames routine is called when we are in some
 121     // informational context (the failure signal handler for example).
 122     // Use the non-strict unwinding rules to produce a stack trace
 123     // that is as complete as possible (even if it contains a few bogus
 124     // entries in some rare cases).
 125     void **next_sp = NextStackFrame<IS_STACK_FRAMES == 0>(sp);
 126
 127     if (skip_count > 0) {
 128       skip_count--;
 129     } else {
 130       result[n] = *sp;
 131
 132 #if IS_STACK_FRAMES
 133       if (next_sp > sp) {
 134         sizes[n] = (uintptr_t)next_sp - (uintptr_t)sp;
 135       } else {
 136         // A frame-size of 0 is used to indicate unknown frame size.
 137         sizes[n] = 0;
 138       }
 139 #endif
 140       n++;
 141     }
 142     sp = next_sp;
 143   }
 144   return n;
 145 }