From db8aedc745faea10b10f96b2dca9e29543192e68 Mon Sep 17 00:00:00 2001
From: Zou Nan hai <nanhai.zou@intel.com>
Date: Wed, 21 Apr 2010 11:02:21 +0800
Subject: [PATCH] use left recursion instead of right recursion to avoid memory
 exhausted issue when compiling large source files

---
 assembler/src/gen4asm.h |  1 +
 assembler/src/gram.y    | 37 +++++++++++++++++++++++++------------
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/assembler/src/gen4asm.h b/assembler/src/gen4asm.h
index a965d112..c67d94ed 100644
--- a/assembler/src/gen4asm.h
+++ b/assembler/src/gen4asm.h
@@ -122,6 +122,7 @@ struct brw_program_instruction {
  */
 struct brw_program {
 	struct brw_program_instruction *first;
+	struct brw_program_instruction *last;
 };
 
 extern struct brw_program compiled_program;
diff --git a/assembler/src/gram.y b/assembler/src/gram.y
index 4d061f30..438559a2 100644
--- a/assembler/src/gram.y
+++ b/assembler/src/gram.y
@@ -174,16 +174,15 @@ ROOT:		instrseq
 label:          STRING COLON
 ;
 
-instrseq:	instruction SEMICOLON instrseq
+instrseq:	instrseq instruction SEMICOLON 
 		{
 		  struct brw_program_instruction *list_entry =
 		    calloc(sizeof(struct brw_program_instruction), 1);
-		  list_entry->instruction = $1;
-
-		  list_entry->next = $3.first;
-		  $3.first = list_entry;
-
-		  $$ = $3;
+		  list_entry->instruction = $2;
+		  list_entry->next = NULL;
+		  $1.last->next = list_entry;
+		  $1.last = list_entry;
+		  $$ = $1;
 		}
 		| instruction SEMICOLON
 		{
@@ -194,17 +193,31 @@ instrseq:	instruction SEMICOLON instrseq
 		  list_entry->next = NULL;
 
 		  $$.first = list_entry;
+		  $$.last = list_entry;
 		}
-                | label instrseq
+                | instrseq label
                 {
                   struct brw_program_instruction *list_entry =
                     calloc(sizeof(struct brw_program_instruction), 1);
+                  list_entry->string = strdup($2);
+                  list_entry->islabel = 1;
+		  list_entry->next = NULL;
+		  $1.last->next = list_entry;
+		  $1.last = list_entry;
+		  $$ = $1;
+                }
+		| label
+		{
+		  struct brw_program_instruction *list_entry =
+		    calloc(sizeof(struct brw_program_instruction), 1);
                   list_entry->string = strdup($1);
                   list_entry->islabel = 1;
-                  list_entry->next = $2.first;
-                      $2.first = list_entry;
-                      $$ = $2;
-                }
+
+		  list_entry->next = NULL;
+
+		  $$.first = list_entry;
+		  $$.last = list_entry;
+		}
 		| error SEMICOLON instrseq
 		{
 		  $$ = $3;