commit bfec3a315000e9fcfc8e2d3fcef25e747e3d2053
author Elliott Hughes <enh@google.com> Thu May 24 19:03:07 2012 -0700
committer Brian Carlstrom <bdc@google.com> Tue May 14 19:49:22 2013 -0700
tree 8e8c717620381e8f480470cce4517b54d57ed729
parent 7382459eca9632168b9d393bc77fb62bc21bb67a

Add basic Darwin support to libcorkscrew.

This might not seem like much, but it's already better than Mac OS'
backtrace(3).

(cherry picked from commit 2a46f6293f19b9d6100187fbd53088088e671b88)

Change-Id: I197b06c4c19f728ad6f194b2f473bd9dcd99b8a6

libcorkscrew/arch-x86/backtrace-x86.c

diff --git a/libcorkscrew/arch-x86/backtrace-x86.c b/libcorkscrew/arch-x86/backtrace-x86.c
index 29159ed..e133ab6 100755
--- a/libcorkscrew/arch-x86/backtrace-x86.c
+++ b/libcorkscrew/arch-x86/backtrace-x86.c
@@ -75,13 +75,18 @@
 
 #endif /* __BIONIC_HAVE_UCONTEXT_T */
 
-#else /* __BIONIC__ */
+#elif defined(__APPLE__)
+
+#define _XOPEN_SOURCE
+#include <ucontext.h>
+
+#else
 
 // glibc has its own renaming of the Linux kernel's structures.
 #define __USE_GNU // For REG_EBP, REG_ESP, and REG_EIP.
 #include <ucontext.h>
 
-#endif /* __ BIONIC__ */
+#endif
 
 /* Unwind state. */
 typedef struct {
@@ -819,9 +824,15 @@
     const ucontext_t* uc = (const ucontext_t*)sigcontext;
 
     unwind_state_t state;
+#if defined(__APPLE__)
+    state.reg[DWARF_EBP] = uc->uc_mcontext->__ss.__ebp;
+    state.reg[DWARF_ESP] = uc->uc_mcontext->__ss.__esp;
+    state.reg[DWARF_EIP] = uc->uc_mcontext->__ss.__eip;
+#else
     state.reg[DWARF_EBP] = uc->uc_mcontext.gregs[REG_EBP];
     state.reg[DWARF_ESP] = uc->uc_mcontext.gregs[REG_ESP];
     state.reg[DWARF_EIP] = uc->uc_mcontext.gregs[REG_EIP];
+#endif
 
     memory_t memory;
     init_memory(&memory, map_info_list);
@@ -831,6 +842,9 @@
 
 ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
         backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+#if defined(__APPLE__)
+    return -1;
+#else
     pt_regs_x86_t regs;
     if (ptrace(PTRACE_GETREGS, tid, 0, &regs)) {
         return -1;
@@ -845,4 +859,5 @@
     init_memory_ptrace(&memory, tid);
     return unwind_backtrace_common(&memory, context->map_info_list,
             &state, backtrace, ignore_depth, max_depth);
+#endif
 }