Compiler: Improve/fix recursion detection.

Imported from Pawn 3.2.3664 and 3.3.3875.

compiler/libpc300/sc1.c

@@ -105,7 +105,7 @@ static void doarg(char *name,int ident,int offset,int tags[],int numtags,
                   int fpublic,int fconst,arginfo *arg);
 static void make_report(symbol *root,FILE *log,char *sourcefile);
 static void reduce_referrers(symbol *root);
-static long max_stacksize(symbol *root);
+static long max_stacksize(symbol *root, int *recursion);
 static int testsymbols(symbol *root,int level,int testlabs,int testconst);
 static void destructsymbols(symbol *root,int level);
 static constvalue *find_constval_byval(constvalue *table,cell val);
@@ -718,7 +718,8 @@ cleanup:
 
   #if !defined SC_LIGHT
     if (errnum==0 && strlen(errfname)==0) {
-      long stacksize=max_stacksize(&glbtab);
+      int recursion;
+      long stacksize=max_stacksize(&glbtab,&recursion);
       int flag_exceed=0;
       if (sc_amxlimit > 0 && (long)(hdrsize+code_idx+glb_declared*sizeof(cell)+sc_stksize*sizeof(cell)) >= sc_amxlimit)
         flag_exceed=1;
@@ -4247,29 +4248,47 @@ static void reduce_referrers(symbol *root)
 }
 
 #if !defined SC_LIGHT
-static long max_stacksize_recurse(symbol *sourcesym, symbol *sym, long basesize, int *pubfuncparams)
+static long max_stacksize_recurse(symbol **sourcesym,symbol *sym,long basesize,int *pubfuncparams,int *recursion)
 {
   long size,maxsize;
-  int i;
+  int i,stkpos;
 
+  assert(sourcesym!=NULL);
   assert(sym!=NULL);
   assert(sym->ident==iFUNCTN);
   assert((sym->usage & uNATIVE)==0);
+  assert(recursion!=NULL);
 
   maxsize=sym->x.stacksize;
   for (i=0; i<sym->numrefers; i++) {
     if (sym->refer[i]!=NULL) {
       assert(sym->refer[i]->ident==iFUNCTN);
       assert((sym->refer[i]->usage & uNATIVE)==0); /* a native function cannot refer to a user-function */
-      if (sym->refer[i] == sourcesym)
-        return -1;      /* recursion detection */
-      size = max_stacksize_recurse(sourcesym, sym->refer[i], sym->x.stacksize, pubfuncparams);
-      if (size<0)
-        return size;    /* recursion was detected, quit */
+      for (stkpos=0; sourcesym[stkpos]!=NULL; stkpos++) {
+        if (sym->refer[i]==sourcesym[stkpos]) {   /* recursion detection */
+          if ((sc_debug & sSYMBOLIC)!=0 || verbosity>=2) {
+            char symname[2*sNAMEMAX+16];/* allow space for user defined operators */
+            funcdisplayname(symname,sym->name);
+            errorset(sSETFILE,sym->fnumber);
+            errorset(sSETLINE,sym->lnumber);
+            error(237,symname);         /* recursive function */
+          } /* if */
+          *recursion=1;
+          goto break_recursion;         /* recursion was detected, quit loop */
+        } /* if */
+      } /* for */
+      /* add this symbol to the stack */
+      sourcesym[stkpos]=sym;
+      sourcesym[stkpos+1]=NULL;
+      /* check size of callee */
+      size=max_stacksize_recurse(sourcesym,sym->refer[i],sym->x.stacksize,pubfuncparams,recursion);
       if (maxsize<size)
         maxsize=size;
+      /* remove this symbol from the stack */
+      sourcesym[stkpos]=NULL;
     } /* if */
   } /* for */
+  break_recursion:
 
   if ((sym->usage & uPUBLIC)!=0) {
     /* Find out how many parameters a public function has, then see if this
@@ -4287,10 +4306,13 @@ static long max_stacksize_recurse(symbol *sourcesym, symbol *sym, long basesize,
       *pubfuncparams=count;
   } /* if */
 
+  errorset(sEXPRRELEASE,0); /* clear error data */
+  errorset(sRESET,0);
+
   return maxsize+basesize;
 }
 
-static long max_stacksize(symbol *root)
+static long max_stacksize(symbol *root,int *recursion)
 {
   /* Loop over all non-native functions. For each function, loop
    * over all of its referrers, accumulating the stack requirements.
@@ -4303,29 +4325,44 @@ static long max_stacksize(symbol *root)
    * stack requirements are thus only an estimate.
    */
   long size,maxsize;
-  int maxparams;
+  int maxparams,numfunctions;
   symbol *sym;
+  symbol **symstack;
 
-  #if !defined NDEBUG
-    for (sym=root->next; sym!=NULL; sym=sym->next)
-      if (sym->ident==iFUNCTN)
-        assert(sym->compound==0);
-  #endif
+  assert(root!=NULL);
+  assert(recursion!=NULL);
+  /* count number of functions (for allocating the stack for recursion detection) */
+  numfunctions=0;
+  for (sym=root->next; sym!=NULL; sym=sym->next) {
+    if (sym->ident==iFUNCTN) {
+      assert(sym->compound==0);
+      if ((sym->usage & uNATIVE)==0)
+        numfunctions++;
+    } /* if */
+  } /* if */
+  /* allocate function symbol stack */
+  symstack=(symbol **)malloc((numfunctions+1)*sizeof(symbol*));
+  if (symstack==NULL)
+    error(103);         /* insufficient memory (fatal error) */
+  memset(symstack,0,(numfunctions+1)*sizeof(symbol*));
 
   maxsize=0;
   maxparams=0;
+  *recursion=0;         /* assume no recursion */
   for (sym=root->next; sym!=NULL; sym=sym->next) {
     /* drop out if this is not a user-implemented function */
     if (sym->ident!=iFUNCTN || (sym->usage & uNATIVE)!=0)
       continue;
     /* accumulate stack size for this symbol */
-    size=max_stacksize_recurse(sym,sym,0L,&maxparams);
-    if (size<0)
-      return size;      /* recursion was detected */
+    symstack[0]=sym;
+    assert(symstack[1]==NULL);
+    size=max_stacksize_recurse(symstack,sym,0L,&maxparams,recursion);
+    assert(size>=0);
     if (maxsize<size)
       maxsize=size;
   } /* for */
 
+  free((void*)symstack);
   maxsize++;                  /* +1 because a zero cell is always pushed on top
                                * of the stack to catch stack overwrites */
   return maxsize+(maxparams+1);/* +1 because # of parameters is always pushed on entry */