Misused posix_memalign results in memory leak and returning wrong lib index (#296)

(cherry picked from commit dcfc396)

Author: zhengyu123

ddprof-lib/src/main/cpp/codeCache.cpp

@@ -6,13 +6,15 @@
 #include "codeCache.h"
 #include "dwarf_dd.h"
 #include "os_dd.h"
+
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
 
 char *NativeFunc::create(const char *name, short lib_index) {
-  NativeFunc *f = (NativeFunc *)malloc(sizeof(NativeFunc) + 1 + strlen(name));
+  size_t size = align_up(sizeof(NativeFunc) + 1 + strlen(name), sizeof(NativeFunc*));
+  NativeFunc *f = (NativeFunc *)aligned_alloc(sizeof(NativeFunc*), size);
   f->_lib_index = lib_index;
   f->_mark = 0;
   // cppcheck-suppress memleak

ddprof-lib/src/main/cpp/codeCache.h

@@ -6,6 +6,8 @@
 #ifndef _CODECACHE_H
 #define _CODECACHE_H
 
+#include "utils.h"
+
 #include <jvmti.h>
 #include <stdlib.h>
 #include <string.h>
@@ -62,7 +64,7 @@ class NativeFunc {
 
   static short libIndex(const char *name) {
     NativeFunc* func = from(name);
-    if (posix_memalign((void**)(&func), sizeof(NativeFunc*), sizeof(NativeFunc)) != 0) {
+    if (!is_aligned(func, sizeof(func))) {
       return -1;
     }
     return func->_lib_index;

ddprof-lib/src/main/cpp/utils.h

@@ -0,0 +1,35 @@
+#ifndef _UTILS_H
+#define _UTILS_H
+
+#include <cassert>
+#include <cstdint>
+#include <cstddef>
+
+inline bool is_power_of_2(size_t size) {
+    return size > 0 && (size & (size - 1)) == 0;
+}
+
+template <typename T>
+inline bool is_aligned(const T* ptr, size_t alignment) noexcept {
+    assert(is_power_of_2(alignment));
+    // Convert the pointer to an integer type
+    auto iptr = reinterpret_cast<uintptr_t>(ptr);
+
+    // Check if the integer value is a multiple of the alignment
+    return (iptr & ~(alignment - 1) == 0);
+}
+
+inline size_t align_down(size_t size, size_t alignment) noexcept {
+    assert(is_power_of_2(alignment));
+    return size & ~(alignment - 1);
+}
+
+inline size_t align_up(size_t size, size_t alignment) noexcept {
+    assert(is_power_of_2(alignment));
+    return align_down(size + alignment - 1, alignment);
+}
+
+
+
+
+#endif // _UTILS_H