heaptrace: Resolve some warnings found by clang-tidy

This patch fixes the following clang-tidy warnings.

  src/heaptrace.cc:117:8: warning: Value stored to 'old_libpath' during
    its initialization is never read
  src/libheaptrace.cc:71:8: warning: Value stored to 'tfs' during its
    initialization is never read
  src/libheaptrace.cc:171:24: warning: function previously declared with
    an explicit exception specification red eclared with an implicit
    exception specification
  src/libheaptrace.cc:189:24: warning: function previously declared with
    an explicit exception specification red eclared with an implicit
    exception specification
  src/stacktrace.cc:310:10: warning: Value stored to 'count' during its
    initialization is never read
  src/utils.cc:24:2: warning: Value stored to 'ret' is never read

Signed-off-by: Honggyu Kim <[email protected]>

src/heaptrace.cc

@@ -114,7 +114,6 @@ static void setup_child_environ(struct opts *opts, int argc, char *argv[])
 	std::stringstream ss;
 	char buf[4096];
 	char *old_preload = getenv("LD_PRELOAD");
-	char *old_libpath = getenv("LD_LIBRARY_PATH");
 
 	if (!access("libheaptrace.so", X_OK))
 		ss << "./";

src/libheaptrace.cc

@@ -68,7 +68,6 @@ FILE *outfp;
 
 __constructor static void heaptrace_init()
 {
-	auto *tfs = &thread_flags;
 	int pid = getpid();
 	std::stringstream ss;
 	std::string comm = utils::get_comm_name();
@@ -169,7 +168,7 @@ __visible_default void *operator new[](size_t size)
 	return p;
 }
 
-__visible_default void operator delete(void *ptr)
+__visible_default void operator delete(void *ptr) noexcept
 {
 	auto *tfs = &thread_flags;
 
@@ -187,7 +186,7 @@ __visible_default void operator delete(void *ptr)
 	tfs->hook_guard = false;
 }
 
-__visible_default void operator delete[](void *ptr)
+__visible_default void operator delete[](void *ptr) noexcept
 {
 	auto *tfs = &thread_flags;
 

src/stacktrace.cc

@@ -307,7 +307,6 @@ print_dump_stackmap_flamegraph(std::vector<std::pair<stack_trace_t, stack_info_t
 	size_t stack_size = sorted_stack.size();
 	for (int i = 0; i < stack_size; i++) {
 		const stack_info_t &info = sorted_stack[i].second;
-		size_t count = info.count;
 		uint64_t size = info.total_size;
 		const char *semicolon = "";
 

src/utils.cc

@@ -18,10 +18,12 @@ std::string asprintf(const char *fmt, ...)
 	va_list args;
 	std::string str;
 	char *ptr;
-	int ret;
 
 	va_start(args, fmt);
-	ret = vasprintf(&ptr, fmt, args);
+	if (vasprintf(&ptr, fmt, args) < 0) {
+		va_end(args);
+		return {};
+	}
 	str = ptr;
 	free(ptr);
 	va_end(args);