Recover from longjmp Error handling in profiling

Previously, profiling did not detect when Error caused one or more
functions to exit. This lead to incorrect and very deep stack
traces.

src/profile.c

@@ -14,6 +14,7 @@
 #include <src/bool.h>
 #include <src/calls.h>
 #include <src/code.h>
+#include <src/funcs.h>
 #include <src/error.h>
 #include <src/hookintrprtr.h>
 #include <src/io.h>
@@ -95,7 +96,6 @@
 **  never marked as executed.
 */
 
-
 /****************************************************************************
 **
 ** Store the current state of the profiler
@@ -146,11 +146,56 @@ struct ProfileState
   ** clear */
   UInt profiledPreviously;
 
+  Int LongJmpOccurred;
+
+  // We store the value of RecursionDepth each time we enter a function.
+  // This is the only way to detect if GAP has left a function by performing
+  // a longjmp.
+  // We need to store the actual values, as RecursionDepth can increase
+  // by more than one when a GAP function is called
+  Obj visitedDepths;
 } profileState;
 
 /* We keep this seperate as it is exported for use in other files */
 UInt profileState_Active;
 
+
+static void ProfileRegisterLongJmpOccurred(void)
+{
+    profileState.LongJmpOccurred = 1;
+}
+
+// This function is called when we detect a longjmp occurred, and
+// outputs a 'return' into the profile for any function which was
+// jumped over.
+// It is fine for this function to be called when a longjmp has not
+// occurred, or when no function was longjmped over.
+static void CheckLeaveFunctionsAfterLongjmp(void)
+{
+    if (!profileState.LongJmpOccurred)
+        return;
+
+#ifdef HPCGAP
+    if (profileState.profiledThread != TLS(threadID))
+        return;
+#endif
+
+    profileState.LongJmpOccurred = 0;
+
+    Int pos = LEN_PLIST(profileState.visitedDepths);
+    Int depth = GetRecursionDepth();
+
+    while (pos > 0 && INT_INTOBJ(ELM_PLIST(profileState.visitedDepths, pos)) > depth) {
+        // Give dummy values if we do not know
+        fprintf(profileState.Stream,
+                "{\"Type\":\"O\",\"Fun\":\"nameless\",\"Line\":-1,"
+                "\"EndLine\":-1,\"File\":\"<missing filename>\","
+                "\"FileId\":-1}\n");
+        PopPlist(profileState.visitedDepths);
+        pos--;
+    }
+}
+
 static inline void outputFilenameIdIfRequired(UInt id)
 {
     if (id == 0) {
@@ -213,10 +258,32 @@ void HookedLineOutput(Obj func, char type)
 }
 
 void enterFunction(Obj func)
-{ HookedLineOutput(func, 'I'); }
+{
+#ifdef HPCGAP
+    if (profileState.profiledThread != TLS(threadID)) 
+      return;
+#endif
+    CheckLeaveFunctionsAfterLongjmp();
+    PushPlist(profileState.visitedDepths, INTOBJ_INT(GetRecursionDepth()));
+    HookedLineOutput(func, 'I');
+}
 
 void leaveFunction(Obj func)
-{ HookedLineOutput(func, 'O'); }
+{
+#ifdef HPCGAP
+    if (profileState.profiledThread != TLS(threadID))
+      return;
+#endif
+    // Do not crash if we exit the function in which
+    // Profile was originally called. The profiling
+    // package can handle such profiles.
+    if (LEN_PLIST(profileState.visitedDepths) > 0) {
+        PopPlist(profileState.visitedDepths);
+    }
+    CheckLeaveFunctionsAfterLongjmp();
+
+    HookedLineOutput(func, 'O');
+}
 
 /****************************************************************************
 **
@@ -306,6 +373,8 @@ static inline void outputStat(Stat stat, int exec, int visited)
   UInt line;
   int nameid;
 
+  CheckLeaveFunctionsAfterLongjmp();
+
   Int8 ticks = 0, newticks = 0;
 
   // Explicitly skip these two cases, as they are often specially handled
@@ -459,6 +528,7 @@ void enableAtStartup(char * filename, Int repeats, TickMethod tickMethod)
     ActivateHooks(&profileHooks);
 
     profileState_Active = 1;
+    RegisterSyLongjmpObserver(ProfileRegisterLongJmpOccurred);
     profileState.profiledPreviously = 1;
 #ifdef HPCGAP
     profileState.profiledThread = TLS(threadID);
@@ -520,7 +590,10 @@ Obj FuncACTIVATE_PROFILING(Obj self,
         return Fail;
     }
 
+    memset(&profileState, 0, sizeof(profileState));
+
     OutputtedFilenameList = NEW_PLIST(T_PLIST, 0);
+    profileState.visitedDepths = NEW_PLIST(T_PLIST, 0);
 
     if ( ! IsStringConv( filename ) ) {
         ErrorMayQuit("<filename> must be a string",0,0);
@@ -588,6 +661,7 @@ Obj FuncACTIVATE_PROFILING(Obj self,
     }
 
     profileState_Active = 1;
+    RegisterSyLongjmpObserver(ProfileRegisterLongJmpOccurred);
     profileState.profiledPreviously = 1;
 #ifdef HPCGAP
     profileState.profiledThread = TLS(threadID);
@@ -786,6 +860,7 @@ static Int InitLibrary (
     /* init filters and functions                                          */
     InitGVarFuncsFromTable( GVarFuncs );
 
+    profileState.visitedDepths = NEW_PLIST(T_PLIST, 0);
     OutputtedFilenameList = NEW_PLIST(T_PLIST, 0);
     /* return success                                                      */
     return 0;
@@ -800,6 +875,7 @@ static Int InitKernel (
 {
     InitHdlrFuncsFromTable( GVarFuncs );
     InitGlobalBag(&OutputtedFilenameList, "src/profile.c:OutputtedFileList");
+    InitGlobalBag(&profileState.visitedDepths, "src/profile.c:visitedDepths");
     return 0;
 }