From: Carl Worth Date: Fri, 20 Dec 2013 00:06:31 +0000 (-0800) Subject: glcpp: Replace multi-line comment with a space (even as part of macro definition) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6005e9cb283214cd57038c7c5e7758ba72ec6ac2;p=mesa.git glcpp: Replace multi-line comment with a space (even as part of macro definition) The preprocessor has always replaced multi-line comments with a single space character, (as required by the specification), but as of commit bd55ba568b301d0f764cd1ca015e84e1ae932c8b the lexer also emitted a NEWLINE token for each newline within the comment, (in order to preserve line numbers). The emitting of NEWLINE tokens within the comment broke the rule of "replace a multi-line comment with a single space" as could be exposed by code like the following: #define FOO a/* */b FOO Prior to commit bd55ba568b301d0f764cd1ca015e84e1ae932c8b, this code defined the macro FOO as "a b" as desired. Since that commit, this code instead defines FOO as "a" and leaves a stray "b" in the output. In this commit, we fix this by not emitting the NEWLINE tokens while lexing the comment, but instead merely counting them in the commented_newlines variable. Then, when the lexer next encounters a non-commented newline it switches to a NEWLINE_CATCHUP state to emit as many NEWLINE tokens as necessary (so that subsequent parsing stages still generate correct line numbers). Of course, it would have been more clear if we could have written a loop to emit all the newlines, but flex conventions prevent that, (we must use "return" for each token we emit). It similarly would have been clear to have a new rule restricted to the state with an action much like the body of this if condition. The problem with that is that this rule must not consume any characters. It might be possible to write a rule that matches a single lookahead of any character, but then we would also need an additional rule to ensure for the case where there are no additional characters available for the lookahead to match. Given those considerations, and given that the SKIP-state manipulation already involves a code block at the top of the lexer function, before any rules, it seems best to me to go with the implementation here which adds a similar pre-rule code block for the NEWLINE_CATCHUP. Finally, this commit also changes the expected output of a few, existing glcpp tests. The change here is that the space character resulting from the multi-line comment is now emitted before the newlines corresponding to that comment. (Previously, the newlines were emitted first, and the space character afterward.) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72686 Reviewed-by: Kenneth Graunke Reviewed-by: Ian Romanick --- diff --git a/src/glsl/glcpp/glcpp-lex.l b/src/glsl/glcpp/glcpp-lex.l index f1db165d199..f1fa192c5f4 100644 --- a/src/glsl/glcpp/glcpp-lex.l +++ b/src/glsl/glcpp/glcpp-lex.l @@ -67,7 +67,7 @@ void glcpp_set_column (int column_no , yyscan_t yyscanner); %option stack %option never-interactive -%x DONE COMMENT UNREACHABLE SKIP DEFINE +%x DONE COMMENT UNREACHABLE SKIP DEFINE NEWLINE_CATCHUP SPACE [[:space:]] NONSPACE [^[:space:]] @@ -93,6 +93,25 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? %% + glcpp_parser_t *parser = yyextra; + + /* When we lex a multi-line comment, we replace it (as + * specified) with a single space. But if the comment spanned + * multiple lines, then subsequent parsing stages will not + * count correct line numbers. To avoid this problem we keep + * track of all newlines that were commented out by a + * multi-line comment, and we emit a NEWLINE token for each at + * the next legal opportunity, (which is when the lexer would + * be emitting a NEWLINE token anyway). + */ + if (YY_START == NEWLINE_CATCHUP) { + if (parser->commented_newlines) + parser->commented_newlines--; + if (parser->commented_newlines == 0) + BEGIN INITIAL; + return NEWLINE; + } + /* The handling of the SKIP vs INITIAL start states requires * some special handling. Typically, a lexer would change * start states with statements like "BEGIN SKIP" within the @@ -123,7 +142,6 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? * expression so the parser can correctly update the * skip_stack state. */ - glcpp_parser_t *parser = yyextra; if (YY_START == INITIAL || YY_START == SKIP) { if (parser->lexing_if || parser->skip_stack == NULL || @@ -137,14 +155,16 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? /* Single-line comments */ "//"[^\n]* { + if (parser->commented_newlines) + BEGIN NEWLINE_CATCHUP; } /* Multi-line comments */ "/*" { yy_push_state(COMMENT, yyscanner); } [^*\n]* -[^*\n]*\n { yylineno++; yycolumn = 0; return NEWLINE; } +[^*\n]*\n { yylineno++; yycolumn = 0; parser->commented_newlines++; } "*"+[^*/\n]* -"*"+[^*/\n]*\n { yylineno++; yycolumn = 0; return NEWLINE; } +"*"+[^*/\n]*\n { yylineno++; yycolumn = 0; parser->commented_newlines++; } "*"+"/" { yy_pop_state(yyscanner); if (yyextra->space_tokens) @@ -160,6 +180,8 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? /* glcpp doesn't handle #extension, #version, or #pragma directives. * Simply pass them through to the main compiler's lexer/parser. */ {HASH}(extension|pragma)[^\n]+ { + if (parser->commented_newlines) + BEGIN NEWLINE_CATCHUP; yylval->str = ralloc_strdup (yyextra, yytext); yylineno++; yycolumn = 0; @@ -206,7 +228,10 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? } } -[^\n] ; +[^\n] { + if (parser->commented_newlines) + BEGIN NEWLINE_CATCHUP; +} {HASH}error.* { char *p; @@ -321,6 +346,9 @@ HEXADECIMAL_INTEGER 0[xX][0-9a-fA-F]+[uU]? } \n { + if (parser->commented_newlines) { + BEGIN NEWLINE_CATCHUP; + } yyextra->lexing_if = 0; yylineno++; yycolumn = 0; diff --git a/src/glsl/glcpp/glcpp-parse.y b/src/glsl/glcpp/glcpp-parse.y index 7edc27488a0..5474577ebe4 100644 --- a/src/glsl/glcpp/glcpp-parse.y +++ b/src/glsl/glcpp/glcpp-parse.y @@ -1164,6 +1164,7 @@ glcpp_parser_create (const struct gl_extensions *extensions, int api) parser->newline_as_space = 0; parser->in_control_line = 0; parser->paren_count = 0; + parser->commented_newlines = 0; parser->skip_stack = NULL; diff --git a/src/glsl/glcpp/glcpp.h b/src/glsl/glcpp/glcpp.h index 8aaa551d128..e95ab8497d8 100644 --- a/src/glsl/glcpp/glcpp.h +++ b/src/glsl/glcpp/glcpp.h @@ -172,6 +172,7 @@ struct glcpp_parser { int newline_as_space; int in_control_line; int paren_count; + int commented_newlines; skip_node_t *skip_stack; token_list_t *lex_from_list; token_node_t *lex_from_node; diff --git a/src/glsl/glcpp/tests/063-comments.c.expected b/src/glsl/glcpp/tests/063-comments.c.expected index 73ca7071faa..1965c9be02d 100644 --- a/src/glsl/glcpp/tests/063-comments.c.expected +++ b/src/glsl/glcpp/tests/063-comments.c.expected @@ -5,16 +5,16 @@ f = g /h; l(); m = n + p; + - more code here - + are not treated like comments. diff --git a/src/glsl/glcpp/tests/094-divide-by-zero-short-circuit.c.expected b/src/glsl/glcpp/tests/094-divide-by-zero-short-circuit.c.expected index 84fdc50c920..be20b7c8909 100644 --- a/src/glsl/glcpp/tests/094-divide-by-zero-short-circuit.c.expected +++ b/src/glsl/glcpp/tests/094-divide-by-zero-short-circuit.c.expected @@ -1,4 +1,5 @@ 0:12(17): preprocessor error: division by 0 in preprocessor directive + @@ -9,7 +10,6 @@ - diff --git a/src/glsl/glcpp/tests/117-line-continuation-and-non-continuation-backslash.c.expected b/src/glsl/glcpp/tests/117-line-continuation-and-non-continuation-backslash.c.expected index 9b3eb676f08..292d6516fe0 100644 --- a/src/glsl/glcpp/tests/117-line-continuation-and-non-continuation-backslash.c.expected +++ b/src/glsl/glcpp/tests/117-line-continuation-and-non-continuation-backslash.c.expected @@ -1,3 +1,4 @@ + @@ -6,7 +7,6 @@ - diff --git a/src/glsl/glcpp/tests/118-comment-becomes-space.c b/src/glsl/glcpp/tests/118-comment-becomes-space.c new file mode 100644 index 00000000000..53e80394ab6 --- /dev/null +++ b/src/glsl/glcpp/tests/118-comment-becomes-space.c @@ -0,0 +1,4 @@ +#define FOO first/* +*/second + +FOO diff --git a/src/glsl/glcpp/tests/118-comment-becomes-space.c.expected b/src/glsl/glcpp/tests/118-comment-becomes-space.c.expected new file mode 100644 index 00000000000..2adf5d1ba90 --- /dev/null +++ b/src/glsl/glcpp/tests/118-comment-becomes-space.c.expected @@ -0,0 +1,5 @@ + + + +first second +