From d3df641f0aba99b0b65ecd4d9b06798bca090a29 Mon Sep 17 00:00:00 2001 From: Carl Worth Date: Mon, 23 Aug 2010 11:38:45 -0700 Subject: [PATCH] glcpp: Demote "macro redefined" from an error to a warning The GLSL specification is vague here, (just says "as is standard for C++"), though the C specifications seem quite clear that this should be an error. However, an existing piglit test (CorrectPreprocess11.frag) expects this to be a warning, not an error, so we change this, and document in README the deviation from the specification. --- src/glsl/glcpp/README | 25 ++++++++++++++++++- src/glsl/glcpp/glcpp-parse.c | 8 +++--- src/glsl/glcpp/glcpp-parse.y | 8 +++--- .../tests/089-redefine-macro-error.c.expected | 12 ++++----- 4 files changed, 38 insertions(+), 15 deletions(-) diff --git a/src/glsl/glcpp/README b/src/glsl/glcpp/README index 0b5ef508ce9..9cc00e92750 100644 --- a/src/glsl/glcpp/README +++ b/src/glsl/glcpp/README @@ -29,4 +29,27 @@ The __LINE__ and __FILE__ macros are not yet supported. A file that ends with a function-like macro name as the last non-whitespace token will result in a parse error, (where it should be -passed through as is). \ No newline at end of file +passed through as is). + +Known deviations from the specification +--------------------------------------- +As mentoned above, the GLSL specification (as of 1.30.10) is fairly +vague on some aspects of the preprocessor, and we've been using C99 to +fill in details. Here is a list of cases where we have deviated from +the behavior specified in C99 to obtain better compatibility with +other GLSL implementations: + + * Redefining a macro with a different value + + C89 says that a macro "may be redefined ... provided that the + second definition [is equivalent]" (Section 3.8.3 Macro + Replacement/constraints) + + C99 is even more explicit, saying tthat a macro "shall not be + redefined by another #define preprocessing directive unless the + second definition [is equivalent]" (Section 6.10.3 Macro + Replacement/Constraints) + + In spite of this, glcpp emits a warning rather than an error for + non-equivalent redefinition of macros since this matches the + behavior of other, widely-used implementations. diff --git a/src/glsl/glcpp/glcpp-parse.c b/src/glsl/glcpp/glcpp-parse.c index 8567bda1e5d..2bf96e035e1 100644 --- a/src/glsl/glcpp/glcpp-parse.c +++ b/src/glsl/glcpp/glcpp-parse.c @@ -4012,8 +4012,8 @@ _define_object_macro (glcpp_parser_t *parser, talloc_free (macro); return; } - glcpp_error (loc, parser, "Redefinition of macro %s\n", - identifier); + glcpp_warning (loc, parser, "Redefinition of macro %s\n", + identifier); } hash_table_insert (parser->defines, macro, identifier); @@ -4043,8 +4043,8 @@ _define_function_macro (glcpp_parser_t *parser, talloc_free (macro); return; } - glcpp_error (loc, parser, "Redefinition of macro %s\n", - identifier); + glcpp_warning (loc, parser, "Redefinition of macro %s\n", + identifier); } hash_table_insert (parser->defines, macro, identifier); diff --git a/src/glsl/glcpp/glcpp-parse.y b/src/glsl/glcpp/glcpp-parse.y index b449eb288b8..797e614280b 100644 --- a/src/glsl/glcpp/glcpp-parse.y +++ b/src/glsl/glcpp/glcpp-parse.y @@ -1687,8 +1687,8 @@ _define_object_macro (glcpp_parser_t *parser, talloc_free (macro); return; } - glcpp_error (loc, parser, "Redefinition of macro %s\n", - identifier); + glcpp_warning (loc, parser, "Redefinition of macro %s\n", + identifier); } hash_table_insert (parser->defines, macro, identifier); @@ -1718,8 +1718,8 @@ _define_function_macro (glcpp_parser_t *parser, talloc_free (macro); return; } - glcpp_error (loc, parser, "Redefinition of macro %s\n", - identifier); + glcpp_warning (loc, parser, "Redefinition of macro %s\n", + identifier); } hash_table_insert (parser->defines, macro, identifier); diff --git a/src/glsl/glcpp/tests/089-redefine-macro-error.c.expected b/src/glsl/glcpp/tests/089-redefine-macro-error.c.expected index 6209ead559e..4c92e1dd4a6 100644 --- a/src/glsl/glcpp/tests/089-redefine-macro-error.c.expected +++ b/src/glsl/glcpp/tests/089-redefine-macro-error.c.expected @@ -1,14 +1,14 @@ -0:2(9): preprocessor error: Redefinition of macro x +0:2(9): preprocessor warning: Redefinition of macro x -0:5(9): preprocessor error: Redefinition of macro abc +0:5(9): preprocessor warning: Redefinition of macro abc -0:8(9): preprocessor error: Redefinition of macro foo +0:8(9): preprocessor warning: Redefinition of macro foo -0:11(9): preprocessor error: Redefinition of macro bar +0:11(9): preprocessor warning: Redefinition of macro bar -0:14(9): preprocessor error: Redefinition of macro biff +0:14(9): preprocessor warning: Redefinition of macro biff -0:17(9): preprocessor error: Redefinition of macro oper +0:17(9): preprocessor warning: Redefinition of macro oper -- 2.30.2