[Mesa-dev] [PATCH] glsl: fixer lexer for unreachable defines

[Timothy Arceri]

If we have something like:

   #ifdef NOT_DEFINED
   #define A_MACRO(x) \
	if (x)
   #endif

The # on the #define is not skipped but the define itself is so
this then gets recognised as #if.

Until 28a3731e3f this didn't happen because we ended up in
<HASH>{NONSPACE} where BEGIN INITIAL was called stopping the
problem from happening.

This change makes sure we never call RETURN_TOKEN_NEVER_SKIP for
if/else/endif when processing a define.

Cc: Ian Romanick <idr at freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107772
---
 src/compiler/glsl/glcpp/glcpp-lex.l | 60 ++++++++++++++++++-----------
 src/compiler/glsl/glcpp/glcpp.h     |  1 +
 2 files changed, 38 insertions(+), 23 deletions(-)

diff --git a/src/compiler/glsl/glcpp/glcpp-lex.l b/src/compiler/glsl/glcpp/glcpp-lex.l
index fe5845acd4e..f7003da0cc8 100644
--- a/src/compiler/glsl/glcpp/glcpp-lex.l
+++ b/src/compiler/glsl/glcpp/glcpp-lex.l
@@ -289,6 +289,7 @@ HEXADECIMAL_INTEGER	0[xX][0-9a-fA-F]+[uU]?
          * token. */
 	if (parser->first_non_space_token_this_line) {
 		BEGIN HASH;
+		yyextra->in_define = false;
 	}
 
 	RETURN_TOKEN_NEVER_SKIP (HASH_TOKEN);
@@ -336,43 +337,55 @@ HEXADECIMAL_INTEGER	0[xX][0-9a-fA-F]+[uU]?
 	/* For the pre-processor directives, we return these tokens
 	 * even when we are otherwise skipping. */
 <HASH>ifdef {
-	BEGIN INITIAL;
-	yyextra->lexing_directive = 1;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (IFDEF);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->lexing_directive = 1;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (IFDEF);
+	}
 }
 
 <HASH>ifndef {
-	BEGIN INITIAL;
-	yyextra->lexing_directive = 1;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (IFNDEF);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->lexing_directive = 1;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (IFNDEF);
+	}
 }
 
 <HASH>if/[^_a-zA-Z0-9] {
-	BEGIN INITIAL;
-	yyextra->lexing_directive = 1;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (IF);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->lexing_directive = 1;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (IF);
+	}
 }
 
 <HASH>elif/[^_a-zA-Z0-9] {
-	BEGIN INITIAL;
-	yyextra->lexing_directive = 1;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (ELIF);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->lexing_directive = 1;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (ELIF);
+	}
 }
 
 <HASH>else {
-	BEGIN INITIAL;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (ELSE);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (ELSE);
+	}
 }
 
 <HASH>endif {
-	BEGIN INITIAL;
-	yyextra->space_tokens = 0;
-	RETURN_TOKEN_NEVER_SKIP (ENDIF);
+	if (!yyextra->in_define) {
+		BEGIN INITIAL;
+		yyextra->space_tokens = 0;
+		RETURN_TOKEN_NEVER_SKIP (ENDIF);
+	}
 }
 
 <HASH>error[^\r\n]* {
@@ -399,7 +412,8 @@ HEXADECIMAL_INTEGER	0[xX][0-9a-fA-F]+[uU]?
 	 *	  and not whitespace). This will generate an error.
 	 */
 <HASH>define{HSPACE}* {
-	if (! parser->skipping) {
+	yyextra->in_define = true;
+	if (!parser->skipping) {
 		BEGIN DEFINE;
 		yyextra->space_tokens = 0;
 		RETURN_TOKEN (DEFINE_TOKEN);
diff --git a/src/compiler/glsl/glcpp/glcpp.h b/src/compiler/glsl/glcpp/glcpp.h
index c7e382ed30c..e786b24b132 100644
--- a/src/compiler/glsl/glcpp/glcpp.h
+++ b/src/compiler/glsl/glcpp/glcpp.h
@@ -197,6 +197,7 @@ struct glcpp_parser {
 	int first_non_space_token_this_line;
 	int newline_as_space;
 	int in_control_line;
+	bool in_define;
 	int paren_count;
 	int commented_newlines;
 	skip_node_t *skip_stack;
-- 
2.17.1