diff options
Diffstat (limited to 'gcc-4.2.1/gcc/c-pch.c')
| -rw-r--r-- | gcc-4.2.1/gcc/c-pch.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/gcc-4.2.1/gcc/c-pch.c b/gcc-4.2.1/gcc/c-pch.c new file mode 100644 index 000000000..76e40fb0a --- /dev/null +++ b/gcc-4.2.1/gcc/c-pch.c @@ -0,0 +1,481 @@ +/* Precompiled header implementation for the C languages. + Copyright (C) 2000, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GCC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING. If not, write to +the Free Software Foundation, 51 Franklin Street, Fifth Floor, +Boston, MA 02110-1301, USA. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "version.h" +#include "cpplib.h" +#include "tree.h" +#include "flags.h" +#include "c-common.h" +#include "output.h" +#include "toplev.h" +#include "debug.h" +#include "c-pragma.h" +#include "ggc.h" +#include "langhooks.h" +#include "hosthooks.h" +#include "target.h" + +/* This is a list of flag variables that must match exactly, and their + names for the error message. The possible values for *flag_var must + fit in a 'signed char'. */ + +static const struct c_pch_matching +{ + int *flag_var; + const char *flag_name; +} pch_matching[] = { + { &flag_exceptions, "-fexceptions" }, + { &flag_unit_at_a_time, "-funit-at-a-time" } +}; + +enum { + MATCH_SIZE = ARRAY_SIZE (pch_matching) +}; + +/* The value of the checksum in the dummy compiler that is actually + checksummed. That compiler should never be run. */ +static const char no_checksum[16] = { 0 }; + +/* Information about flags and suchlike that affect PCH validity. + + Before this structure is read, both an initial 8-character identification + string, and a 16-byte checksum, have been read and validated. */ + +struct c_pch_validity +{ + unsigned char debug_info_type; + signed char match[MATCH_SIZE]; + void (*pch_init) (void); + size_t target_data_length; +}; + +struct c_pch_header +{ + unsigned long asm_size; +}; + +#define IDENT_LENGTH 8 + +/* The file we'll be writing the PCH to. */ +static FILE *pch_outfile; + +/* The position in the assembler output file when pch_init was called. */ +static long asm_file_startpos; + +static const char *get_ident (void); + +/* Compute an appropriate 8-byte magic number for the PCH file, so that + utilities like file(1) can identify it, and so that GCC can quickly + ignore non-PCH files and PCH files that are of a completely different + format. */ + +static const char * +get_ident (void) +{ + static char result[IDENT_LENGTH]; + static const char template[IDENT_LENGTH] = "gpch.013"; + static const char c_language_chars[] = "Co+O"; + + memcpy (result, template, IDENT_LENGTH); + result[4] = c_language_chars[c_language]; + + return result; +} + +/* Prepare to write a PCH file, if one is being written. This is + called at the start of compilation. + + Also, print out the executable checksum if -fverbose-asm is in effect. */ + +void +pch_init (void) +{ + FILE *f; + struct c_pch_validity v; + void *target_validity; + static const char partial_pch[IDENT_LENGTH] = "gpcWrite"; + +#ifdef ASM_COMMENT_START + if (flag_verbose_asm) + { + fprintf (asm_out_file, "%s ", ASM_COMMENT_START); + c_common_print_pch_checksum (asm_out_file); + fputc ('\n', asm_out_file); + } +#endif + + if (!pch_file) + return; + + f = fopen (pch_file, "w+b"); + if (f == NULL) + fatal_error ("can%'t create precompiled header %s: %m", pch_file); + pch_outfile = f; + + gcc_assert (memcmp (executable_checksum, no_checksum, 16) != 0); + + v.debug_info_type = write_symbols; + { + size_t i; + for (i = 0; i < MATCH_SIZE; i++) + { + v.match[i] = *pch_matching[i].flag_var; + gcc_assert (v.match[i] == *pch_matching[i].flag_var); + } + } + v.pch_init = &pch_init; + target_validity = targetm.get_pch_validity (&v.target_data_length); + + if (fwrite (partial_pch, IDENT_LENGTH, 1, f) != 1 + || fwrite (executable_checksum, 16, 1, f) != 1 + || fwrite (&v, sizeof (v), 1, f) != 1 + || fwrite (target_validity, v.target_data_length, 1, f) != 1) + fatal_error ("can%'t write to %s: %m", pch_file); + + /* We need to be able to re-read the output. */ + /* The driver always provides a valid -o option. */ + if (asm_file_name == NULL + || strcmp (asm_file_name, "-") == 0) + fatal_error ("%qs is not a valid output file", asm_file_name); + + asm_file_startpos = ftell (asm_out_file); + + /* Let the debugging format deal with the PCHness. */ + (*debug_hooks->handle_pch) (0); + + cpp_save_state (parse_in, f); +} + +/* Write the PCH file. This is called at the end of a compilation which + will produce a PCH file. */ + +void +c_common_write_pch (void) +{ + char *buf; + long asm_file_end; + long written; + struct c_pch_header h; + + (*debug_hooks->handle_pch) (1); + + cpp_write_pch_deps (parse_in, pch_outfile); + + asm_file_end = ftell (asm_out_file); + h.asm_size = asm_file_end - asm_file_startpos; + + if (fwrite (&h, sizeof (h), 1, pch_outfile) != 1) + fatal_error ("can%'t write %s: %m", pch_file); + + buf = XNEWVEC (char, 16384); + + if (fseek (asm_out_file, asm_file_startpos, SEEK_SET) != 0) + fatal_error ("can%'t seek in %s: %m", asm_file_name); + + for (written = asm_file_startpos; written < asm_file_end; ) + { + long size = asm_file_end - written; + if (size > 16384) + size = 16384; + if (fread (buf, size, 1, asm_out_file) != 1) + fatal_error ("can%'t read %s: %m", asm_file_name); + if (fwrite (buf, size, 1, pch_outfile) != 1) + fatal_error ("can%'t write %s: %m", pch_file); + written += size; + } + free (buf); + /* asm_out_file can be written afterwards, so fseek to clear + _IOREAD flag. */ + if (fseek (asm_out_file, 0, SEEK_END) != 0) + fatal_error ("can%'t seek in %s: %m", asm_file_name); + + gt_pch_save (pch_outfile); + cpp_write_pch_state (parse_in, pch_outfile); + + if (fseek (pch_outfile, 0, SEEK_SET) != 0 + || fwrite (get_ident (), IDENT_LENGTH, 1, pch_outfile) != 1) + fatal_error ("can%'t write %s: %m", pch_file); + + fclose (pch_outfile); +} + +/* Check the PCH file called NAME, open on FD, to see if it can be + used in this compilation. Return 1 if valid, 0 if the file can't + be used now but might be if it's seen later in the compilation, and + 2 if this file could never be used in the compilation. */ + +int +c_common_valid_pch (cpp_reader *pfile, const char *name, int fd) +{ + int sizeread; + int result; + char ident[IDENT_LENGTH + 16]; + const char *pch_ident; + struct c_pch_validity v; + + /* Perform a quick test of whether this is a valid + precompiled header for the current language. */ + + gcc_assert (memcmp (executable_checksum, no_checksum, 16) != 0); + + sizeread = read (fd, ident, IDENT_LENGTH + 16); + if (sizeread == -1) + fatal_error ("can%'t read %s: %m", name); + else if (sizeread != IDENT_LENGTH + 16) + { + cpp_error (pfile, CPP_DL_WARNING, "%s: too short to be a PCH file", + name); + return 2; + } + + pch_ident = get_ident(); + if (memcmp (ident, pch_ident, IDENT_LENGTH) != 0) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + { + if (memcmp (ident, pch_ident, 5) == 0) + /* It's a PCH, for the right language, but has the wrong version. + */ + cpp_error (pfile, CPP_DL_WARNING, + "%s: not compatible with this GCC version", name); + else if (memcmp (ident, pch_ident, 4) == 0) + /* It's a PCH for the wrong language. */ + cpp_error (pfile, CPP_DL_WARNING, "%s: not for %s", name, + lang_hooks.name); + else + /* Not any kind of PCH. */ + cpp_error (pfile, CPP_DL_WARNING, "%s: not a PCH file", name); + } + return 2; + } + if (memcmp (ident + IDENT_LENGTH, executable_checksum, 16) != 0) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + cpp_error (pfile, CPP_DL_WARNING, + "%s: created by a different GCC executable", name); + return 2; + } + + /* At this point, we know it's a PCH file created by this + executable, so it ought to be long enough that we can read a + c_pch_validity structure. */ + if (read (fd, &v, sizeof (v)) != sizeof (v)) + fatal_error ("can%'t read %s: %m", name); + + /* The allowable debug info combinations are that either the PCH file + was built with the same as is being used now, or the PCH file was + built for some kind of debug info but now none is in use. */ + if (v.debug_info_type != write_symbols + && write_symbols != NO_DEBUG) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + cpp_error (pfile, CPP_DL_WARNING, + "%s: created with -g%s, but used with -g%s", name, + debug_type_names[v.debug_info_type], + debug_type_names[write_symbols]); + return 2; + } + + /* Check flags that must match exactly. */ + { + size_t i; + for (i = 0; i < MATCH_SIZE; i++) + if (*pch_matching[i].flag_var != v.match[i]) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + cpp_error (pfile, CPP_DL_WARNING, + "%s: settings for %s do not match", name, + pch_matching[i].flag_name); + return 2; + } + } + + /* If the text segment was not loaded at the same address as it was + when the PCH file was created, function pointers loaded from the + PCH will not be valid. We could in theory remap all the function + pointers, but no support for that exists at present. + Since we have the same executable, it should only be necessary to + check one function. */ + if (v.pch_init != &pch_init) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + cpp_error (pfile, CPP_DL_WARNING, + "%s: had text segment at different address", name); + return 2; + } + + /* Check the target-specific validity data. */ + { + void *this_file_data = xmalloc (v.target_data_length); + const char *msg; + + if ((size_t) read (fd, this_file_data, v.target_data_length) + != v.target_data_length) + fatal_error ("can%'t read %s: %m", name); + msg = targetm.pch_valid_p (this_file_data, v.target_data_length); + free (this_file_data); + if (msg != NULL) + { + if (cpp_get_options (pfile)->warn_invalid_pch) + cpp_error (pfile, CPP_DL_WARNING, "%s: %s", name, msg); + return 2; + } + } + + /* Check the preprocessor macros are the same as when the PCH was + generated. */ + + result = cpp_valid_state (pfile, name, fd); + if (result == -1) + return 2; + else + return result == 0; +} + +/* If non-NULL, this function is called after a precompile header file + is loaded. */ +void (*lang_post_pch_load) (void); + +/* Load in the PCH file NAME, open on FD. It was originally searched for + by ORIG_NAME. */ + +void +c_common_read_pch (cpp_reader *pfile, const char *name, + int fd, const char *orig_name ATTRIBUTE_UNUSED) +{ + FILE *f; + struct c_pch_header h; + struct save_macro_data *smd; + + f = fdopen (fd, "rb"); + if (f == NULL) + { + cpp_errno (pfile, CPP_DL_ERROR, "calling fdopen"); + return; + } + + cpp_get_callbacks (parse_in)->valid_pch = NULL; + + if (fread (&h, sizeof (h), 1, f) != 1) + { + cpp_errno (pfile, CPP_DL_ERROR, "reading"); + return; + } + + if (!flag_preprocess_only) + { + unsigned long written; + char * buf = XNEWVEC (char, 16384); + + for (written = 0; written < h.asm_size; ) + { + long size = h.asm_size - written; + if (size > 16384) + size = 16384; + if (fread (buf, size, 1, f) != 1 + || fwrite (buf, size, 1, asm_out_file) != 1) + cpp_errno (pfile, CPP_DL_ERROR, "reading"); + written += size; + } + free (buf); + } + else + { + /* If we're preprocessing, don't write to a NULL + asm_out_file. */ + if (fseek (f, h.asm_size, SEEK_CUR) != 0) + cpp_errno (pfile, CPP_DL_ERROR, "seeking"); + } + + cpp_prepare_state (pfile, &smd); + + gt_pch_restore (f); + + if (cpp_read_state (pfile, name, f, smd) != 0) + return; + + fclose (f); + + /* Give the front end a chance to take action after a PCH file has + been loaded. */ + if (lang_post_pch_load) + (*lang_post_pch_load) (); +} + +/* Indicate that no more PCH files should be read. */ + +void +c_common_no_more_pch (void) +{ + if (cpp_get_callbacks (parse_in)->valid_pch) + { + cpp_get_callbacks (parse_in)->valid_pch = NULL; + host_hooks.gt_pch_use_address (NULL, 0, -1, 0); + } +} + +/* Handle #pragma GCC pch_preprocess, to load in the PCH file. */ + +#ifndef O_BINARY +# define O_BINARY 0 +#endif + +void +c_common_pch_pragma (cpp_reader *pfile, const char *name) +{ + int fd; + + if (!cpp_get_options (pfile)->preprocessed) + { + error ("pch_preprocess pragma should only be used with -fpreprocessed"); + inform ("use #include instead"); + return; + } + + fd = open (name, O_RDONLY | O_BINARY, 0666); + if (fd == -1) + fatal_error ("%s: couldn%'t open PCH file: %m", name); + + if (c_common_valid_pch (pfile, name, fd) != 1) + { + if (!cpp_get_options (pfile)->warn_invalid_pch) + inform ("use -Winvalid-pch for more information"); + fatal_error ("%s: PCH file was invalid", name); + } + + c_common_read_pch (pfile, name, fd, name); + + close (fd); +} + +/* Print out executable_checksum[]. */ + +void +c_common_print_pch_checksum (FILE *f) +{ + int i; + fputs ("Compiler executable checksum: ", f); + for (i = 0; i < 16; i++) + fprintf (f, "%02x", executable_checksum[i]); + putc ('\n', f); +} |