Merge pull request twitter#126 from kevyang/kevyang/120

add debug oriented memory management

CMakeLists.txt

@@ -51,6 +51,7 @@ option(HAVE_ASSERT_LOG "assert_log enabled by default" ON)
 option(HAVE_ASSERT_PANIC "assert_panic disabled by default" OFF)
 option(HAVE_LOGGING "logging enabled by default" ON)
 option(HAVE_STATS "stats enabled by default" ON)
+option(HAVE_DEBUG_MM "debugging oriented memory management disabled by default" OFF)
 option(COVERAGE "code coverage" OFF)
 
 include(CheckIncludeFiles)

config.h.in

@@ -17,3 +17,5 @@
 #cmakedefine HAVE_LOGGING
 
 #cmakedefine HAVE_STATS
+
+#cmakedefine HAVE_DEBUG_MM

include/cc_define.h

@@ -54,10 +54,9 @@ extern "C" {
 # define CC_BACKTRACE 1
 #endif
 
-/* TODO: add compile time option to turn chaining on/off */
-/*#ifdef HAVE_CHAINED*/
-# define CC_HAVE_CHAINED 1
-/*#endif*/
+#ifdef HAVE_DEBUG_MM
+#define CC_DEBUG_MM 1
+#endif
 
 #define CC_OK        0
 #define CC_ERROR    -1

include/cc_mm.h

@@ -17,6 +17,8 @@
 
 #pragma once
 
+#include <cc_define.h>
+
 #include <stddef.h>
 
 /*
@@ -41,8 +43,13 @@
 #define cc_calloc(_n, _s)                                       \
     _cc_calloc((size_t)(_n), (size_t)(_s), __FILE__, __LINE__)
 
+#if defined CC_DEBUG_MM && CC_DEBUG_MM == 1
+#define cc_realloc(_p, _s)                                      \
+    _cc_realloc_move(_p, (size_t)(_s), __FILE__, __LINE__)
+#else
 #define cc_realloc(_p, _s)                                      \
     _cc_realloc(_p, (size_t)(_s), __FILE__, __LINE__)
+#endif
 
 #define cc_free(_p) do {                                        \
     _cc_free(_p, __FILE__, __LINE__);                           \
@@ -59,6 +66,7 @@ void * _cc_alloc(size_t size, const char *name, int line);
 void * _cc_zalloc(size_t size, const char *name, int line);
 void * _cc_calloc(size_t nmemb, size_t size, const char *name, int line);
 void * _cc_realloc(void *ptr, size_t size, const char *name, int line);
+void * _cc_realloc_move(void *ptr, size_t size, const char *name, int line);
 void _cc_free(void *ptr, const char *name, int line);
 void * _cc_mmap(size_t size, const char *name, int line);
 int _cc_munmap(void *p, size_t size, const char *name, int line);

src/cc_mm.c

@@ -34,7 +34,10 @@ _cc_alloc(size_t size, const char *name, int line)
 {
     void *p;
 
-    ASSERT(size != 0);
+    if (size == 0) {
+        log_debug("malloc(0) @ %s:%d", name, line);
+        return NULL;
+    }
 
     p = malloc(size);
     if (p == NULL) {
@@ -70,7 +73,11 @@ _cc_realloc(void *ptr, size_t size, const char *name, int line)
 {
     void *p;
 
-    ASSERT(size != 0);
+    if (size == 0) {
+        free(ptr);
+        log_debug("realloc(0) @ %s:%d", name, line);
+        return NULL;
+    }
 
     p = realloc(ptr, size);
     if (p == NULL) {
@@ -82,10 +89,37 @@ _cc_realloc(void *ptr, size_t size, const char *name, int line)
     return p;
 }
 
+void *
+_cc_realloc_move(void *ptr, size_t size, const char *name, int line)
+{
+    void *p = NULL, *pr;
+
+    if (size == 0) {
+        free(ptr);
+        log_debug("realloc(0) @ %s:%d", name, line);
+        return NULL;
+    }
+
+    /*
+     * Calling realloc then malloc allows us to force this function call to
+     * change the address of the allocated memory block. realloc ensures we can
+     * copy size bytes, and calling malloc before the realloc'd data is free'd
+     * gives us a new address for the memory object.
+     */
+    if (((pr = realloc(ptr, size)) == NULL || (p = malloc(size)) == NULL)) {
+        log_error("realloc(%zu) failed @ %s:%d", size, name, line);
+    } else {
+        log_vverb("realloc(%zu) at %p @ %s:%d", size, p, name, line);
+        memcpy(p, pr, size);
+    }
+
+    free(pr);
+    return p;
+}
+
 void
 _cc_free(void *ptr, const char *name, int line)
 {
-    ASSERT(ptr != NULL);
     log_vverb("free(%p) @ %s:%d", ptr, name, line);
     free(ptr);
 }
@@ -103,10 +137,10 @@ _cc_mmap(size_t size, const char *name, int line)
      * is set appropriately.
      */
     p = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS,
-             -1, 0);
+            -1, 0);
     if (p == ((void *) -1)) {
         log_error("mmap %zu bytes @ %s:%d failed: %s", size, name, line,
-                  strerror(errno));
+                strerror(errno));
         return NULL;
     }
 
@@ -128,7 +162,7 @@ _cc_munmap(void *p, size_t size, const char *name, int line)
     status = munmap(p, size);
     if (status < 0) {
         log_error("munmap %p @ %s:%d failed: %s", p, name, line,
-                  strerror(errno));
+                strerror(errno));
     }
 
     return status;