better stacktraces

print.cpp

@@ -119,11 +119,30 @@ void trace(String* string) {
 
         // the names as provided by 'backtrace_symbols' are mangled for some reason.
         // we have to demangle them, using this weird api
-        // example mangled name (wrapped in double quotes):
+        // example mangled names (wrapped in double quotes):
         // "2   shard_tracy                         0x00000001032d5618 _ZL17drawSettingsPanelv + 904"
+        // "2   shard                               0x000000010ed8be34 _ZN6ShaderC2EPKcS1_P5ArrayIS1_ES1_ + 1108"
+        // "12  shard                               0x000000010ed5edeb main + 43"
+        //
+        // the rule for finding the 'first' character is annoying, because it's usually but not always starting with an underscore,
+        // and when it is an underscore it's usually but not always the first underscore in the string.
         char buffer[1024];
-        const char* mangledNameBegin = String::lastCharOccurence(traces[i], '_');
         const char* mangledNameEnd = String::lastCharOccurence(traces[i], '+'); // it actually ends one char before.
+        const char* mangledNameBegin = null;
+
+        if (mangledNameEnd != null && ((mangledNameEnd - traces[i]) > 2)) {
+            const char* cursor = mangledNameEnd - 2;
+            while (cursor != traces[i]) {
+                if (*cursor == '_') {
+                    mangledNameBegin = cursor;
+
+                } else if (*cursor == ' ') {
+                    mangledNameBegin = cursor + 1;
+                    break;
+                }
+                cursor--;
+            }
+        }
 
         if (mangledNameBegin == null || mangledNameEnd == null) {
             // we can't demangle this name for some reason, just copy the mangled name to the buffer
@@ -132,7 +151,7 @@ void trace(String* string) {
             buffer[length] = '\0';
 
         } else {
-            size_t length = mangledNameEnd - 1 - mangledNameBegin;
+            size_t length = mangledNameEnd - mangledNameBegin - 1;
             String::memcpy(buffer, (void*)mangledNameBegin, length);
             buffer[length] = '\0';
         }
@@ -140,9 +159,20 @@ void trace(String* string) {
         s32 status = -1;
         char* trace = abi::__cxa_demangle(buffer, null, null, &status);
         if (trace == null) {
-            println("warning: failed to demangle name: %s, exit status of attempt: %d", traces[i], status);
-            // just write back the original trace, un-demangled.
-            trace = traces[i];
+            // @HACK, both 'main' and 'start' symbols will fail to be demangled, and we don't really care about printing them
+            // in most cases. your application (certainly true for us) will have its own endpoint which itself is of questionable
+            // usefulness to print, but 'main' and 'start' are even less useful.
+            if (String::memeq((const unsigned char*)(mangledNameBegin), (const unsigned char*)"main", sizeof("main") - 1)) {
+                continue;
+
+            } else if (String::memeq((const unsigned char*)(mangledNameBegin), (const unsigned char*)"start", sizeof("start") - 1)) {
+                continue;
+
+            } else {
+                println("warning: failed to demangle name: %s, exit status of attempt: %d", traces[i], status);
+                // just write back the original trace, un-demangled.
+                trace = traces[i];
+            }
         }
 
         if (string == null) {