1 files changed, 89 insertions, 38 deletions

diff --git a/src/interfaces/ecpg/preproc/pgc.l b/src/interfaces/ecpg/preproc/pgc.l
index 996718c..c06b2d6 100644
--- a/src/interfaces/ecpg/preproc/pgc.l
+++ b/src/interfaces/ecpg/preproc/pgc.l
@@ -69,7 +69,14 @@ char *token_start;
 static int state_before_str_start;
 static int state_before_str_stop;
 
-struct _yy_buffer
+/*
+ * State for handling include files and macro expansion.  We use a new
+ * flex input buffer for each level of include or macro, and create a
+ * struct _yy_buffer to remember the previous level.  There is not a struct
+ * for the currently active input source; that state is kept in the global
+ * variables YY_CURRENT_BUFFER, yylineno, and input_filename.
+ */
+static struct _yy_buffer
 {
 	YY_BUFFER_STATE		buffer;
 	long				lineno;
@@ -77,8 +84,6 @@ struct _yy_buffer
 	struct _yy_buffer  *next;
 } *yy_buffer = NULL;
 
-static char *old;
-
 /*
  * Vars for handling ifdef/elif/endif constructs.  preproc_tos is the current
  * nesting depth of such constructs, and stacked_if_value[preproc_tos] is the
@@ -432,6 +437,8 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 
 %{
 		/* code to execute during start of each call of yylex() */
+		char *newdefsymbol = NULL;
+
 		token_start = NULL;
 %}
 
@@ -979,6 +986,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 				}
 
 {identifier}	{
+					/* First check to see if it's a define symbol to expand */
 					if (!isdefine())
 					{
 						int		kwvalue;
@@ -1171,17 +1179,23 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 					yytext[i+1] = '\0';
 
 
-					for (ptr = defines; ptr != NULL; ptr2 = ptr, ptr = ptr->next)
+					/* Find and unset any matching define; should be only 1 */
+					for (ptr = defines; ptr; ptr2 = ptr, ptr = ptr->next)
 					{
-						if (strcmp(yytext, ptr->olddef) == 0)
+						if (strcmp(yytext, ptr->name) == 0)
 						{
-							if (ptr2 == NULL)
-								defines = ptr->next;
-							else
-								ptr2->next = ptr->next;
-							free(ptr->newdef);
-							free(ptr->olddef);
-							free(ptr);
+							free(ptr->value);
+							ptr->value = NULL;
+							/* We cannot forget it if there's a cmdvalue */
+							if (ptr->cmdvalue == NULL)
+							{
+								if (ptr2 == NULL)
+									defines = ptr->next;
+								else
+									ptr2->next = ptr->next;
+								free(ptr->name);
+								free(ptr);
+							}
 							break;
 						}
 					}
@@ -1386,11 +1400,17 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 							;
 						yytext[i+1] = '\0';
 
-						for (defptr = defines;
-							 defptr != NULL &&
-							 strcmp(yytext, defptr->olddef) != 0;
-							 defptr = defptr->next)
-							/* skip */ ;
+						/* Does a definition exist? */
+						for (defptr = defines; defptr; defptr = defptr->next)
+						{
+							if (strcmp(yytext, defptr->name) == 0)
+							{
+								/* Found it, but is it currently undefined? */
+								if (defptr->value == NULL)
+									defptr = NULL; /* pretend it's not found */
+								break;
+							}
+						}
 
 						this_active = (defptr ? ifcond : !ifcond);
 						stacked_if_value[preproc_tos].active =
@@ -1411,7 +1431,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 				yyterminate();
 			}
 <def_ident>{identifier} {
-				old = mm_strdup(yytext);
+				newdefsymbol = mm_strdup(yytext);
 				BEGIN(def);
 				startlit();
 			}
@@ -1420,26 +1440,31 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 				yyterminate();
 			}
 <def>{space}*";"	{
-						struct _defines *ptr, *this;
+						struct _defines *ptr;
 
+						/* Does it already exist? */
 						for (ptr = defines; ptr != NULL; ptr = ptr->next)
 						{
-							 if (strcmp(old, ptr->olddef) == 0)
-							 {
-								free(ptr->newdef);
-								ptr->newdef = mm_strdup(literalbuf);
-							 }
+							if (strcmp(newdefsymbol, ptr->name) == 0)
+							{
+								free(ptr->value);
+								ptr->value = mm_strdup(literalbuf);
+								/* Don't leak newdefsymbol */
+								free(newdefsymbol);
+								break;
+							}
 						}
 						if (ptr == NULL)
 						{
-							this = (struct _defines *) mm_alloc(sizeof(struct _defines));
-
-							/* initial definition */
-							this->olddef = old;
-							this->newdef = mm_strdup(literalbuf);
-							this->next = defines;
-							this->used = NULL;
-							defines = this;
+							/* Not present, make a new entry */
+							ptr = (struct _defines *) mm_alloc(sizeof(struct _defines));
+
+							ptr->name = newdefsymbol;
+							ptr->value = mm_strdup(literalbuf);
+							ptr->cmdvalue = NULL;
+							ptr->used = NULL;
+							ptr->next = defines;
+							defines = ptr;
 						}
 
 						BEGIN(C);
@@ -1456,6 +1481,7 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 <<EOF>>				{
 					if (yy_buffer == NULL)
 					{
+						/* No more input */
 						if (preproc_tos > 0)
 						{
 							preproc_tos = 0;
@@ -1465,16 +1491,20 @@ cppline			{space}*#([^i][A-Za-z]*|{if}|{ifdef}|{ifndef}|{import})((\/\*[^*/]*\*+
 					}
 					else
 					{
+						/* Revert to previous input source */
 						struct _yy_buffer *yb = yy_buffer;
 						int i;
 						struct _defines *ptr;
 
+						/* Check to see if we are exiting a macro value */
 						for (ptr = defines; ptr; ptr = ptr->next)
+						{
 							if (ptr->used == yy_buffer)
 							{
 								ptr->used = NULL;
-								break;
+								break; /* there can't be multiple matches */
 							}
+						}
 
 						if (yyin != NULL)
 							fclose(yyin);
@@ -1699,15 +1729,24 @@ ecpg_isspace(char ch)
 	return false;
 }
 
-static bool isdefine(void)
+/*
+ * If yytext matches a define symbol, begin scanning the symbol's value
+ * and return true
+ */
+static bool
+isdefine(void)
 {
 	struct _defines *ptr;
 
 	/* is it a define? */
 	for (ptr = defines; ptr; ptr = ptr->next)
 	{
-		if (strcmp(yytext, ptr->olddef) == 0 && ptr->used == NULL)
+		/* notice we do not match anything being actively expanded */
+		if (strcmp(yytext, ptr->name) == 0 &&
+			ptr->value != NULL &&
+			ptr->used == NULL)
 		{
+			/* Save state associated with the current buffer */
 			struct _yy_buffer *yb;
 
 			yb = mm_alloc(sizeof(struct _yy_buffer));
@@ -1716,10 +1755,17 @@ static bool isdefine(void)
 			yb->lineno = yylineno;
 			yb->filename = mm_strdup(input_filename);
 			yb->next = yy_buffer;
+			yy_buffer = yb;
 
-			ptr->used = yy_buffer = yb;
+			/* Mark symbol as being actively expanded */
+			ptr->used = yb;
 
-			yy_scan_string(ptr->newdef);
+			/*
+			 * We use yy_scan_string which will copy the value, so there's
+			 * no need to worry about a possible undef happening while we
+			 * are still scanning it.
+			 */
+			yy_scan_string(ptr->value);
 			return true;
 		}
 	}
@@ -1727,7 +1773,12 @@ static bool isdefine(void)
 	return false;
 }
 
-static bool isinformixdefine(void)
+/*
+ * Handle replacement of INFORMIX built-in defines.  This works just
+ * like isdefine() except for the source of the string to scan.
+ */
+static bool
+isinformixdefine(void)
 {
 	const char *new = NULL;