ref: 82469ac0fde1b2e73bfbfc58853a7ecb95e4a794
parent: 96cb5e10ed87e7f072f9f98440a4139a13ba013d
author: ISSOtm <eldredhabert0@gmail.com>
date: Mon Aug 31 10:27:24 EDT 2020
Shim around `mmap` on Windows
--- a/src/asm/lexer.c
+++ b/src/asm/lexer.c
@@ -6,7 +6,7 @@
* SPDX-License-Identifier: MIT
*/
-#include <sys/mman.h>
+#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <ctype.h>
@@ -22,6 +22,7 @@
#include <unistd.h>
#include "extern/utf8decoder.h"
+#include "platform.h" /* For `mmap` */
#include "asm/asm.h"
#include "asm/lexer.h"
@@ -312,6 +313,48 @@
state->expansionOfs = 0;
}
+/* Neither MSVC nor MinGW provide `mmap` */
+#if defined(_MSC_VER) || defined(__MINGW32__)
+# include <windows.h>
+# include <fileapi.h>
+# include <winbase.h>
+# define MAP_FAILED NULL
+# define mapFile(ptr, fd, path, size) do { \+ HANDLE file = CreateFileA(path, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, \
+ FILE_FLAG_POSIX_SEMANTICS | FILE_FLAG_RANDOM_ACCESS, NULL); \
+ HANDLE mappingObj; \
+ \
+ if (file == INVALID_HANDLE_VALUE) \
+ break; \
+ mappingObj = CreateFileMappingA(file, NULL, PAGE_READONLY, 0, 0, NULL); \
+ (ptr) = mappingObj == INVALID_HANDLE_VALUE \
+ ? NULL \
+ : MapViewOfFile(mappingObj, FILE_MAP_READ, 0, 0, 0); \
+ CloseHandle(mappingObj); \
+ CloseHandle(file); \
+} while (0)
+# define munmap(ptr, size) UnmapViewOfFile((ptr))
+
+#else /* defined(_MSC_VER) || defined(__MINGW32__) */
+
+# include <sys/mman.h>
+# define mapFile(ptr, fd, path, size) do { \+ (ptr) = mmap(NULL, (size), PROT_READ, MAP_PRIVATE, (fd), 0); \
+ \
+ if ((ptr) == MAP_FAILED && errno == ENOTSUP) { \+ /*
+ * The implementation may not support MAP_PRIVATE; try again with MAP_SHARED
+ * instead, offering, I believe, weaker guarantees about external
+ * modifications to the file while reading it. That's still better than not
+ * opening it at all, though.
+ */ \
+ if (verbose) \
+ printf("mmap(%s, MAP_PRIVATE) failed, retrying with MAP_SHARED\n", path); \+ (ptr) = mmap(NULL, (size), PROT_READ, MAP_SHARED, (fd), 0); \
+ } \
+} while (0)
+#endif /* !( defined(_MSC_VER) || defined(__MINGW32__) ) */
+
struct LexerState *lexer_OpenFile(char const *path)
{ dbgPrint("Opening file \"%s\"\n", path);@@ -318,6 +361,7 @@
bool isStdin = !strcmp(path, "-");
struct LexerState *state = malloc(sizeof(*state));
+ struct stat fileInfo;
/* Give stdin a nicer file name */
if (isStdin)
@@ -326,38 +370,27 @@
error("Failed to allocate memory for lexer state: %s\n", strerror(errno));return NULL;
}
- state->path = path;
-
- state->isFile = true;
- state->fd = isStdin ? STDIN_FILENO : open(path, O_RDONLY);
- if (state->fd == -1) {- error("Failed to open file \"%s\": %s\n", path, strerror(errno));+ if (!isStdin && stat(path, &fileInfo) != 0) {+ error("Failed to stat file \"%s\": %s\n", path, strerror(errno));free(state);
return NULL;
}
+ state->path = path;
+ state->isFile = true;
+ state->fd = isStdin ? STDIN_FILENO : open(path, O_RDONLY);
state->isMmapped = false; /* By default, assume it won't be mmap()ed */
- off_t size = lseek(state->fd, 0, SEEK_END);
+ if (!isStdin && fileInfo.st_size > 0) {+ /* Try using `mmap` for better performance */
- if (size != 1) {- /* The file is a regular file, so use `mmap` for better performance */
-
/*
* Important: do NOT assign to `state->ptr` directly, to avoid a cast that may
* alter an eventual `MAP_FAILED` value. It would also invalidate `state->fd`,
* being on the other side of the union.
*/
- void *pa = mmap(NULL, size, PROT_READ, MAP_PRIVATE, state->fd, 0);
+ void *mappingAddr;
- if (pa == MAP_FAILED && errno == ENOTSUP)
- /*
- * The implementation may not support MAP_PRIVATE; try again with MAP_SHARED
- * instead, offering, I believe, weaker guarantees about external
- * modifications to the file while reading it. That's still better than not
- * opening it at all, though.
- */
- pa = mmap(NULL, size, PROT_READ, MAP_SHARED, state->fd, 0);
-
- if (pa == MAP_FAILED) {+ mapFile(mappingAddr, state->fd, state->path, fileInfo.st_size);
+ if (mappingAddr == MAP_FAILED) {/* If mmap()ing failed, try again using another method (below) */
state->isMmapped = false;
} else {@@ -365,8 +398,8 @@
close(state->fd);
state->isMmapped = true;
- state->ptr = pa;
- state->size = size;
+ state->ptr = mappingAddr;
+ state->size = fileInfo.st_size;
state->offset = 0;
if (verbose)
@@ -378,7 +411,6 @@
if (verbose)
printf("File %s opened as regular, errno reports \"%s\"\n",path, strerror(errno));
- lseek(state->fd, 0, SEEK_SET);
state->index = 0;
state->nbChars = 0;
}