!902 Optimize musl I/O function fread

Merge pull request !902 from Wang Yaofeng/master

musl_src.gni

@@ -2165,6 +2165,9 @@ musl_src_porting_file = [
   "src/ldso/riscv64/dlvsym.s",
   "src/ldso/x86_64/dlvsym.s",
   "src/stdio/__fdopen.c",
+  "src/stdio/__stdio_read.c",
+  "src/stdio/fread.c",
+  "src/internal/stdio_impl.h",
   "src/internal/vdso.c",
   "src/time/clock_gettime.c",
   "src/time/clock_getres.c",

porting/linux/user/src/internal/stdio_impl.h

+#ifndef _STDIO_IMPL_H
+#define _STDIO_IMPL_H
+
+#include <stdio.h>
+#include "syscall.h"
+
+#define UNGET 8
+
+#define FFINALLOCK(f) ((f)->lock>=0 ? __lockfile((f)) : 0)
+#define FLOCK(f) int __need_unlock = ((f)->lock>=0 ? __lockfile((f)) : 0)
+#define FUNLOCK(f) do { if (__need_unlock) __unlockfile((f)); } while (0)
+
+#define F_PERM 1
+#define F_NORD 4
+#define F_NOWR 8
+#define F_EOF 16
+#define F_ERR 32
+#define F_SVB 64
+#define F_APP 128
+
+struct _IO_FILE {
+	unsigned flags;
+	unsigned char *rpos, *rend;
+	int (*close)(FILE *);
+	unsigned char *wend, *wpos;
+	unsigned char *mustbezero_1;
+	unsigned char *wbase;
+	size_t (*read)(FILE *, unsigned char *, size_t);
+	size_t (*readx)(FILE *, unsigned char *, size_t);
+	size_t (*write)(FILE *, const unsigned char *, size_t);
+	off_t (*seek)(FILE *, off_t, int);
+	unsigned char *buf;
+	size_t buf_size;
+	FILE *prev, *next;
+	int fd;
+	int pipe_pid;
+	long lockcount;
+	int mode;
+	volatile int lock;
+	int lbf;
+	void *cookie;
+	off_t off;
+	char *getln_buf;
+	void *mustbezero_2;
+	unsigned char *shend;
+	off_t shlim, shcnt;
+	FILE *prev_locked, *next_locked;
+	struct __locale_struct *locale;
+};
+
+extern hidden FILE *volatile __stdin_used;
+extern hidden FILE *volatile __stdout_used;
+extern hidden FILE *volatile __stderr_used;
+
+hidden int __lockfile(FILE *);
+hidden void __unlockfile(FILE *);
+
+hidden size_t __stdio_read(FILE *, unsigned char *, size_t);
+hidden size_t __stdio_readx(FILE *, unsigned char *, size_t);
+hidden size_t __stdio_write(FILE *, const unsigned char *, size_t);
+hidden size_t __stdout_write(FILE *, const unsigned char *, size_t);
+hidden off_t __stdio_seek(FILE *, off_t, int);
+hidden int __stdio_close(FILE *);
+
+hidden int __fill_buffer(FILE *f);
+hidden int __toread(FILE *);
+hidden int __towrite(FILE *);
+
+hidden void __stdio_exit(void);
+hidden void __stdio_exit_needed(void);
+
+#if defined(__PIC__) && (100*__GNUC__+__GNUC_MINOR__ >= 303)
+__attribute__((visibility("protected")))
+#endif
+int __overflow(FILE *, int), __uflow(FILE *);
+
+hidden int __fseeko(FILE *, off_t, int);
+hidden int __fseeko_unlocked(FILE *, off_t, int);
+hidden off_t __ftello(FILE *);
+hidden off_t __ftello_unlocked(FILE *);
+hidden size_t __fwritex(const unsigned char *, size_t, FILE *);
+hidden int __putc_unlocked(int, FILE *);
+
+hidden FILE *__fdopen(int, const char *);
+hidden int __fmodeflags(const char *);
+
+hidden FILE *__ofl_add(FILE *f);
+hidden FILE **__ofl_lock(void);
+hidden void __ofl_unlock(void);
+
+struct __pthread;
+hidden void __register_locked_file(FILE *, struct __pthread *);
+hidden void __unlist_locked_file(FILE *);
+hidden void __do_orphaned_stdio_locks(void);
+
+#define MAYBE_WAITERS 0x40000000
+
+hidden void __getopt_msg(const char *, const char *, const char *, size_t);
+
+#define feof(f) ((f)->flags & F_EOF)
+#define ferror(f) ((f)->flags & F_ERR)
+
+#define getc_unlocked(f) \
+	( ((f)->rpos != (f)->rend) ? *(f)->rpos++ : __uflow((f)) )
+
+#define putc_unlocked(c, f) \
+	( (((unsigned char)(c)!=(f)->lbf && (f)->wpos!=(f)->wend)) \
+	  ? *(f)->wpos++ = (unsigned char)(c) \
+	  : __overflow((f),(unsigned char)(c)) )
+
+/* Caller-allocated FILE * operations */
+hidden FILE *__fopen_rb_ca(const char *, FILE *, unsigned char *, size_t);
+hidden int __fclose_ca(FILE *);
+
+#endif

porting/linux/user/src/stdio/__fdopen.c

@@ -93,6 +93,7 @@ FILE *__fdopen(int fd, const char *mode)
 	f->write = __stdio_write;
 	f->seek = __stdio_seek;
 	f->close = __stdio_close;
+	f->readx = __stdio_readx;
 
 	if (!libc.threaded) {
 		f->lock = -1;

porting/linux/user/src/stdio/__stdio_read.c

+#include "stdio_impl.h"
+#include <sys/uio.h>
+
+size_t __stdio_readx(FILE *f, unsigned char *buf, size_t len)
+{
+	return syscall(SYS_read, f->fd, buf, len);
+}
+
+size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
+{
+	struct iovec iov_buf[2] = {
+		{ .iov_base = buf, .iov_len = len - !!f->buf_size },
+		{ .iov_base = f->buf, .iov_len = f->buf_size }
+	};
+	ssize_t cnt;
+
+	cnt = iov_buf[0].iov_len ? syscall(SYS_readv, f->fd, iov_buf, 2)
+		: syscall(SYS_read, f->fd, iov_buf[1].iov_base, iov_buf[1].iov_len);
+	if (cnt <= 0) {
+		f->flags |= cnt ? F_ERR : F_EOF;
+		return 0;
+	}
+	if (cnt <= iov_buf[0].iov_len) {
+        return cnt;
+    }
+	cnt -= iov_buf[0].iov_len;
+	f->rpos = f->buf;
+	f->rend = f->buf + cnt;
+	if (f->buf_size) buf[len-1] = *f->rpos++;
+	return len;
+}

porting/linux/user/src/stdio/fread.c

+#include "stdio_impl.h"
+#include <string.h>
+
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+int __fill_buffer(FILE *f)
+{
+	int r = __toread(f);
+	if (r != 0) {
+		return r;
+	}
+	int k = f->readx(f, f->buf, f->buf_size);
+	if (k <= 0) {
+		f->flags |= (k == 0) ? F_EOF : F_ERR;
+		f->rpos = f->rend;
+		return k;
+	}
+
+	f->rpos = f->buf;
+	f->rend = f->rpos + k;
+
+	return 0;
+}
+
+size_t fread(void *restrict destv, size_t size, size_t nmemb, FILE *restrict f)
+{
+	unsigned char *dest = destv;
+	size_t len = size * nmemb, l = len, k;
+	if (!size) {
+		nmemb = 0;
+	}
+
+	FLOCK(f);
+
+	f->mode |= f->mode-1;
+
+	while (l > 0) {
+		if (f->rpos != f->rend) {
+			/* First exhaust the buffer. */
+			k = MIN(f->rend - f->rpos, l);
+			memcpy(dest, f->rpos, k);
+			f->rpos += k;
+			dest += k;
+			l -= k;
+		}
+		/* done */
+		if (l == 0) {
+			goto exit;
+		}
+		/* if user buffer is longer than file buffer, read directly */
+		if (l > f->buf_size) {
+			break;
+		}
+
+		if (__fill_buffer(f)) {
+			goto exit;
+		}
+	}
+
+	/* Read the remainder directly */
+	for (; l; l-=k, dest+=k) {
+		k = f->readx(f, dest, l);
+		if (k <= 0) {
+			f->flags |= (k == 0 ? F_EOF : F_ERR);
+			break;
+		}
+	}
+
+exit:
+	FUNLOCK(f);
+	return (len - l) / size;
+}
+
+weak_alias(fread, fread_unlocked);