Merge pull request #6076 from evsh/warn-if-no-function-names

Warn if no function names are present in the stacktrace

src/app/stacktrace.h

@@ -15,10 +15,10 @@ static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames
     fprintf(out, "stack trace:\n");
 
     // storage array for stack trace address data
-    void* addrlist[max_frames+1];
+    void *addrlist[max_frames + 1];
 
     // retrieve current stack addresses
-    int addrlen = backtrace(addrlist, sizeof(addrlist) / sizeof(void*));
+    int addrlen = backtrace(addrlist, sizeof(addrlist) / sizeof(void *));
 
     if (addrlen == 0) {
         fprintf(out, "  <empty, possibly corrupt>\n");
@@ -27,36 +27,36 @@ static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames
 
     // resolve addresses into strings containing "filename(function+address)",
     // this array must be free()-ed
-    char** symbollist = backtrace_symbols(addrlist, addrlen);
+    char * *symbollist = backtrace_symbols(addrlist, addrlen);
 
     // allocate string which will be filled with the demangled function name
     size_t funcnamesize = 256;
-    char* funcname = (char*)malloc(funcnamesize);
+    char *funcname = (char *)malloc(funcnamesize);
 
+    int functionNamesFound = 0;
     // iterate over the returned symbol lines. skip the first, it is the
     // address of this function.
-    for (int i = 2; i < addrlen; i++)
-    {
+    for (int i = 2; i < addrlen; i++) {
         char *begin_name = 0, *begin_offset = 0, *end_offset = 0;
 
         // find parentheses and +address offset surrounding the mangled name:
         // ./module(function+0x15c) [0x8048a6d]
-	//fprintf(out, "%s TT\n", symbollist[i]);
-	for (char *p = symbollist[i]; *p; ++p)
-	{
-	    if (*p == '(')
+        // fprintf(out, "%s TT\n", symbollist[i]);
+        for (char *p = symbollist[i]; *p; ++p) {
+            if (*p == '(') {
                 begin_name = p;
-	    else if (*p == '+')
+            }
+            else if (*p == '+') {
                 begin_offset = p;
-	    else if (*p == ')' && begin_offset) {
+            }
+            else if ((*p == ')') && begin_offset) {
                 end_offset = p;
                 break;
             }
         }
 
         if (begin_name && begin_offset && end_offset
-	    && begin_name < begin_offset)
-	{
+            && (begin_name < begin_offset)) {
             *begin_name++ = '\0';
             *begin_offset++ = '\0';
             *end_offset = '\0';
@@ -66,7 +66,7 @@ static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames
             // __cxa_demangle():
 
             int status;
-	    char* ret = abi::__cxa_demangle(begin_name,
+            char *ret = abi::__cxa_demangle(begin_name,
                                             funcname, &funcnamesize, &status);
             if (status == 0) {
                 funcname = ret; // use possibly realloc()-ed string
@@ -79,14 +79,22 @@ static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames
                 fprintf(out, "  %s : %s()+%s %s\n",
                         symbollist[i], begin_name, begin_offset, ++end_offset);
             }
+            ++functionNamesFound;
         }
-	else
-	{
+        else {
             // couldn't parse the line? print the whole line.
             fprintf(out, "  %s\n", symbollist[i]);
         }
     }
 
+    if (!functionNamesFound) {
+        fprintf(out, "There were no function names found in the stack trace\n."
+            "Seems like debug symbols are not installed, and the stack trace is useless.\n");
+    }
+    if (functionNamesFound < addrlen - 2) {
+        fprintf(out, "Consider installing debug symbols for packages containing files with empty"
+            " function names (i.e. empty braces \"()\") to make your stack trace more useful\n");
+    }
     free(funcname);
     free(symbollist);
 }