Merge changes I5578fe06,I197b06c4

* changes:
  Add flush_my_map_info_list() and fix a bug in the Mac load_map_info_list().
  Add basic Darwin support to libcorkscrew.
diff --git a/include/corkscrew/map_info.h b/include/corkscrew/map_info.h
index c9b241d..14bfad6 100644
--- a/include/corkscrew/map_info.h
+++ b/include/corkscrew/map_info.h
@@ -63,6 +63,10 @@
  * previous acquired using acquire_my_map_info_list(). */
 void release_my_map_info_list(map_info_t* milist);
 
+/* Flushes the cached memory map so the next call to
+ * acquire_my_map_info_list() gets fresh data. */
+void flush_my_map_info_list();
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/libcorkscrew/Android.mk b/libcorkscrew/Android.mk
index 2786d8f..20c48c3 100644
--- a/libcorkscrew/Android.mk
+++ b/libcorkscrew/Android.mk
@@ -59,23 +59,26 @@
 
 # Build test.
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := test.c
-LOCAL_CFLAGS += -std=gnu99 -Werror -fno-inline-small-functions
+LOCAL_SRC_FILES := test.cpp
+LOCAL_CFLAGS += -Werror -fno-inline-small-functions
 LOCAL_SHARED_LIBRARIES := libcorkscrew
 LOCAL_MODULE := libcorkscrew_test
 LOCAL_MODULE_TAGS := optional
 include $(BUILD_EXECUTABLE)
 
 
-ifeq ($(HOST_OS)-$(HOST_ARCH),linux-x86)
+ifeq ($(HOST_ARCH),x86)
 
 # Build libcorkscrew.
 include $(CLEAR_VARS)
 LOCAL_SRC_FILES += $(generic_src_files) $(x86_src_files)
 LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
-LOCAL_SHARED_LIBRARIES += libgccdemangle
 LOCAL_STATIC_LIBRARIES += libcutils
-LOCAL_LDLIBS += -ldl -lrt
+LOCAL_LDLIBS += -ldl
+ifeq ($(HOST_OS),linux)
+  LOCAL_SHARED_LIBRARIES += libgccdemangle # TODO: is this even needed on Linux?
+  LOCAL_LDLIBS += -lrt
+endif
 LOCAL_CFLAGS += -std=gnu99 -Werror
 LOCAL_MODULE := libcorkscrew
 LOCAL_MODULE_TAGS := optional
@@ -83,11 +86,11 @@
 
 # Build test.
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := test.c
-LOCAL_CFLAGS += -std=gnu99 -Werror -fno-inline-small-functions
+LOCAL_SRC_FILES := test.cpp
+LOCAL_CFLAGS += -Werror
 LOCAL_SHARED_LIBRARIES := libcorkscrew
 LOCAL_MODULE := libcorkscrew_test
 LOCAL_MODULE_TAGS := optional
 include $(BUILD_HOST_EXECUTABLE)
 
-endif # linux-x86
+endif # HOST_ARCH == x86
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
 }
diff --git a/libcorkscrew/backtrace.c b/libcorkscrew/backtrace.c
index 03dbd53..b365e5b 100644
--- a/libcorkscrew/backtrace.c
+++ b/libcorkscrew/backtrace.c
@@ -33,7 +33,6 @@
 #include <unwind.h>
 #include <cutils/log.h>
 #include <cutils/atomic.h>
-#include <elf.h>
 
 #define __USE_GNU // For dladdr(3) in glibc.
 #include <dlfcn.h>
@@ -43,6 +42,15 @@
 // Bionic implements and exports gettid but only implements tgkill.
 extern int tgkill(int tgid, int tid, int sig);
 
+#elif defined(__APPLE__)
+
+#include <sys/syscall.h>
+
+// Mac OS >= 10.6 has a system call equivalent to Linux's gettid().
+static pid_t gettid() {
+  return syscall(SYS_thread_selfid);
+}
+
 #else
 
 // glibc doesn't implement or export either gettid or tgkill.
@@ -97,7 +105,7 @@
     state.returned_frames = 0;
     init_memory(&state.memory, milist);
 
-    _Unwind_Reason_Code rc =_Unwind_Backtrace(unwind_backtrace_callback, &state);
+    _Unwind_Reason_Code rc = _Unwind_Backtrace(unwind_backtrace_callback, &state);
 
     release_my_map_info_list(milist);
 
@@ -146,7 +154,9 @@
 
     ALOGV("Unwinding thread %d from thread %d.", tid, gettid());
 
-#ifdef CORKSCREW_HAVE_ARCH
+    // TODO: there's no tgkill(2) on Mac OS, so we'd either need the
+    // mach_port_t or the pthread_t rather than the tid.
+#if defined(CORKSCREW_HAVE_ARCH) && !defined(__APPLE__)
     struct sigaction act;
     struct sigaction oact;
     memset(&act, 0, sizeof(act));
@@ -305,20 +315,20 @@
         const backtrace_symbol_t* symbol, char* buffer, size_t bufferSize) {
     const char* mapName = symbol->map_name ? symbol->map_name : "<unknown>";
     const char* symbolName = symbol->demangled_name ? symbol->demangled_name : symbol->symbol_name;
-    size_t fieldWidth = (bufferSize - 80) / 2;
+    int fieldWidth = (bufferSize - 80) / 2;
     if (symbolName) {
         uint32_t pc_offset = symbol->relative_pc - symbol->relative_symbol_addr;
         if (pc_offset) {
-            snprintf(buffer, bufferSize, "#%02d  pc %08x  %.*s (%.*s+%u)",
-                    frameNumber, symbol->relative_pc, fieldWidth, mapName,
+            snprintf(buffer, bufferSize, "#%02u  pc %p  %.*s (%.*s+%u)",
+                    frameNumber, (void*) symbol->relative_pc, fieldWidth, mapName,
                     fieldWidth, symbolName, pc_offset);
         } else {
-            snprintf(buffer, bufferSize, "#%02d  pc %08x  %.*s (%.*s)",
-                    frameNumber, symbol->relative_pc, fieldWidth, mapName,
+            snprintf(buffer, bufferSize, "#%02u  pc %p  %.*s (%.*s)",
+                    frameNumber, (void*) symbol->relative_pc, fieldWidth, mapName,
                     fieldWidth, symbolName);
         }
     } else {
-        snprintf(buffer, bufferSize, "#%02d  pc %08x  %.*s",
-                frameNumber, symbol->relative_pc, fieldWidth, mapName);
+        snprintf(buffer, bufferSize, "#%02u  pc %p  %.*s",
+                frameNumber, (void*) symbol->relative_pc, fieldWidth, mapName);
     }
 }
diff --git a/libcorkscrew/demangle.c b/libcorkscrew/demangle.c
index 54247cb..30ab1b0 100644
--- a/libcorkscrew/demangle.c
+++ b/libcorkscrew/demangle.c
@@ -25,6 +25,12 @@
                              int *status);
 
 char* demangle_symbol_name(const char* name) {
+#if defined(__APPLE__)
+    // Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7.
+    if (name != NULL && name[0] != '_') {
+        return NULL;
+    }
+#endif
     // __cxa_demangle handles NULL by returning NULL
     return __cxa_demangle(name, 0, 0, 0);
 }
diff --git a/libcorkscrew/map_info.c b/libcorkscrew/map_info.c
index 6a27664..93dffbf 100644
--- a/libcorkscrew/map_info.c
+++ b/libcorkscrew/map_info.c
@@ -29,6 +29,67 @@
 #include <cutils/log.h>
 #include <sys/time.h>
 
+#if defined(__APPLE__)
+
+// Mac OS vmmap(1) output:
+// __TEXT                 0009f000-000a1000 [    8K     8K] r-x/rwx SM=COW  /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
+// 012345678901234567890123456789012345678901234567890123456789
+// 0         1         2         3         4         5
+static map_info_t* parse_vmmap_line(const char* line) {
+    unsigned long int start;
+    unsigned long int end;
+    char permissions[4];
+    int name_pos;
+    if (sscanf(line, "%*21c %lx-%lx [%*13c] %3c/%*3c SM=%*3c  %n",
+               &start, &end, permissions, &name_pos) != 3) {
+        return NULL;
+    }
+
+    const char* name = line + name_pos;
+    size_t name_len = strlen(name);
+
+    map_info_t* mi = calloc(1, sizeof(map_info_t) + name_len);
+    if (mi != NULL) {
+        mi->start = start;
+        mi->end = end;
+        mi->is_readable = permissions[0] == 'r';
+        mi->is_writable = permissions[1] == 'w';
+        mi->is_executable = permissions[2] == 'x';
+        mi->data = NULL;
+        memcpy(mi->name, name, name_len);
+        mi->name[name_len - 1] = '\0';
+        ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
+              "is_readable=%d, is_writable=%d is_executable=%d, name=%s",
+              mi->start, mi->end,
+              mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
+    }
+    return mi;
+}
+
+map_info_t* load_map_info_list(pid_t pid) {
+    char cmd[1024];
+    snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid);
+    FILE* fp = popen(cmd, "r");
+    if (fp == NULL) {
+        return NULL;
+    }
+
+    char line[1024];
+    map_info_t* milist = NULL;
+    while (fgets(line, sizeof(line), fp) != NULL) {
+        map_info_t* mi = parse_vmmap_line(line);
+        if (mi != NULL) {
+            mi->next = milist;
+            milist = mi;
+        }
+    }
+    pclose(fp);
+    return milist;
+}
+
+#else
+
+// Linux /proc/<pid>/maps lines:
 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so\n
 // 012345678901234567890123456789012345678901234567890123456789
 // 0         1         2         3         4         5
@@ -63,9 +124,9 @@
         memcpy(mi->name, name, name_len);
         mi->name[name_len] = '\0';
         ALOGV("Parsed map: start=0x%08x, end=0x%08x, "
-                "is_readable=%d, is_writable=%d, is_executable=%d, name=%s",
-                mi->start, mi->end,
-                mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
+              "is_readable=%d, is_writable=%d, is_executable=%d, name=%s",
+              mi->start, mi->end,
+              mi->is_readable, mi->is_writable, mi->is_executable, mi->name);
     }
     return mi;
 }
@@ -91,6 +152,8 @@
     return milist;
 }
 
+#endif
+
 void free_map_info_list(map_info_t* milist) {
     while (milist) {
         map_info_t* next = milist->next;
@@ -132,11 +195,17 @@
     int64_t timestamp;
 } my_map_info_data_t;
 
-static int64_t now() {
+static int64_t now_ns() {
+#if defined(HAVE_POSIX_CLOCKS)
     struct timespec t;
     t.tv_sec = t.tv_nsec = 0;
     clock_gettime(CLOCK_MONOTONIC, &t);
     return t.tv_sec * 1000000000LL + t.tv_nsec;
+#else
+    struct timeval t;
+    gettimeofday(&t, NULL);
+    return t.tv_sec * 1000000000LL + t.tv_usec * 1000LL;
+#endif
 }
 
 static void dec_ref(map_info_t* milist, my_map_info_data_t* data) {
@@ -150,8 +219,8 @@
 map_info_t* acquire_my_map_info_list() {
     pthread_mutex_lock(&g_my_map_info_list_mutex);
 
-    int64_t time = now();
-    if (g_my_map_info_list) {
+    int64_t time = now_ns();
+    if (g_my_map_info_list != NULL) {
         my_map_info_data_t* data = (my_map_info_data_t*)g_my_map_info_list->data;
         int64_t age = time - data->timestamp;
         if (age >= MAX_CACHE_AGE) {
@@ -163,10 +232,10 @@
         }
     }
 
-    if (!g_my_map_info_list) {
+    if (g_my_map_info_list == NULL) {
         my_map_info_data_t* data = (my_map_info_data_t*)malloc(sizeof(my_map_info_data_t));
         g_my_map_info_list = load_map_info_list(getpid());
-        if (g_my_map_info_list) {
+        if (g_my_map_info_list != NULL) {
             ALOGV("Loaded my_map_info_list %p.", g_my_map_info_list);
             g_my_map_info_list->data = data;
             data->refs = 1;
@@ -196,3 +265,15 @@
         pthread_mutex_unlock(&g_my_map_info_list_mutex);
     }
 }
+
+void flush_my_map_info_list() {
+    pthread_mutex_lock(&g_my_map_info_list_mutex);
+
+    if (g_my_map_info_list != NULL) {
+        my_map_info_data_t* data = (my_map_info_data_t*) g_my_map_info_list->data;
+        dec_ref(g_my_map_info_list, data);
+        g_my_map_info_list = NULL;
+    }
+
+    pthread_mutex_unlock(&g_my_map_info_list_mutex);
+}
diff --git a/libcorkscrew/ptrace.c b/libcorkscrew/ptrace.c
index 776ef69..be58f7f 100644
--- a/libcorkscrew/ptrace.c
+++ b/libcorkscrew/ptrace.c
@@ -46,21 +46,25 @@
 }
 
 bool try_get_word(const memory_t* memory, uintptr_t ptr, uint32_t* out_value) {
-    ALOGV("try_get_word: reading word at 0x%08x", ptr);
+    ALOGV("try_get_word: reading word at %p", (void*) ptr);
     if (ptr & 3) {
-        ALOGV("try_get_word: invalid pointer 0x%08x", ptr);
+        ALOGV("try_get_word: invalid pointer %p", (void*) ptr);
         *out_value = 0xffffffffL;
         return false;
     }
     if (memory->tid < 0) {
         if (!is_readable_map(memory->map_info_list, ptr)) {
-            ALOGV("try_get_word: pointer 0x%08x not in a readable map", ptr);
+            ALOGV("try_get_word: pointer %p not in a readable map", (void*) ptr);
             *out_value = 0xffffffffL;
             return false;
         }
         *out_value = *(uint32_t*)ptr;
         return true;
     } else {
+#if defined(__APPLE__)
+        ALOGV("no ptrace on Mac OS");
+        return false;
+#else
         // ptrace() returns -1 and sets errno when the operation fails.
         // To disambiguate -1 from a valid result, we clear errno beforehand.
         errno = 0;
@@ -71,6 +75,7 @@
             return false;
         }
         return true;
+#endif
     }
 }
 
diff --git a/libcorkscrew/symbol_table.c b/libcorkscrew/symbol_table.c
index 29e4a79..982ccc8 100644
--- a/libcorkscrew/symbol_table.c
+++ b/libcorkscrew/symbol_table.c
@@ -21,13 +21,17 @@
 
 #include <stdbool.h>
 #include <stdlib.h>
-#include <elf.h>
 #include <fcntl.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
 #include <cutils/log.h>
 
+#if defined(__APPLE__)
+#else
+
+#include <elf.h>
+
 static bool is_elf(Elf32_Ehdr* e) {
     return (e->e_ident[EI_MAG0] == ELFMAG0 &&
             e->e_ident[EI_MAG1] == ELFMAG1 &&
@@ -35,6 +39,8 @@
             e->e_ident[EI_MAG3] == ELFMAG3);
 }
 
+#endif
+
 // Compare function for qsort
 static int qcompar(const void *a, const void *b) {
     const symbol_t* asym = (const symbol_t*)a;
@@ -55,6 +61,7 @@
 
 symbol_table_t* load_symbol_table(const char *filename) {
     symbol_table_t* table = NULL;
+#if !defined(__APPLE__)
     ALOGV("Loading symbol table from '%s'.", filename);
 
     int fd = open(filename, O_RDONLY);
@@ -197,6 +204,7 @@
 
 out_close:
     close(fd);
+#endif
 
 out:
     return table;
diff --git a/libcorkscrew/test.c b/libcorkscrew/test.cpp
similarity index 77%
rename from libcorkscrew/test.c
rename to libcorkscrew/test.cpp
index af34c03..22dfa7d 100644
--- a/libcorkscrew/test.c
+++ b/libcorkscrew/test.cpp
@@ -3,11 +3,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void do_backtrace() {
+int do_backtrace(float /* just to test demangling */) {
   const size_t MAX_DEPTH = 32;
   backtrace_frame_t* frames = (backtrace_frame_t*) malloc(sizeof(backtrace_frame_t) * MAX_DEPTH);
   ssize_t frame_count = unwind_backtrace(frames, 0, MAX_DEPTH);
   fprintf(stderr, "frame_count=%d\n", (int) frame_count);
+  if (frame_count <= 0) {
+    return frame_count;
+  }
 
   backtrace_symbol_t* backtrace_symbols = (backtrace_symbol_t*) malloc(sizeof(backtrace_symbol_t) * frame_count);
   get_backtrace_symbols(frames, frame_count, backtrace_symbols);
@@ -31,7 +34,7 @@
         symbol = find_symbol(symbols, frames[i].absolute_pc);
       }
       if (symbol != NULL) {
-        uintptr_t offset = frames[i].absolute_pc - symbol->start;
+        int offset = frames[i].absolute_pc - symbol->start;
         fprintf(stderr, "  %s (%s%+d)\n", line, symbol->name, offset);
       } else {
         fprintf(stderr, "  %s (\?\?\?)\n", line);
@@ -43,22 +46,31 @@
   free_backtrace_symbols(backtrace_symbols, frame_count);
   free(backtrace_symbols);
   free(frames);
+  return frame_count;
 }
 
-__attribute__ ((noinline)) void g() {
-  fprintf(stderr, "g()\n");
-  do_backtrace();
-}
+struct C {
+  int g(int i);
+};
 
-__attribute__ ((noinline)) int f(int i) {
-  fprintf(stderr, "f(%i)\n", i);
+__attribute__ ((noinline)) int C::g(int i) {
   if (i == 0) {
-    g();
-    return 0;
+    return do_backtrace(0.1);
   }
-  return f(i - 1);
+  return g(i - 1);
+}
+
+extern "C" __attribute__ ((noinline)) int f() {
+  C c;
+  return c.g(5);
 }
 
 int main() {
-  return f(5);
+  flush_my_map_info_list();
+  f();
+
+  flush_my_map_info_list();
+  f();
+
+  return 0;
 }