Refine built-in libc files and inliner tool

Since lib/c.h was introduced in the previous commit, both c.c and c.h
contained duplicated definitions. This commit adjusts the files to
remove the duplicated definitions by making c.c include c.h and reuse
the necessary definitions, such as macros and forward declarations.

The inliner tool is also enhanced to generate two functions,
'libc_decl()' and 'libc_impl()'. The compiler will use these functions
to automatically generate the source of c.h and c.c for compiled
programs when needed.

Author: DrXiao

Makefile

@@ -43,15 +43,15 @@ HOST_ARCH = $(shell arch 2>/dev/null)
 SRCDIR := $(shell find src -type d)
 LIBDIR := $(shell find lib -type d)
 
-BUILTIN_LIBC ?= c.c
+BUILTIN_LIBC_SOURCE ?= c.c
+BUILTIN_LIBC_HEADER := c.h
 STAGE0_FLAGS ?= --dump-ir
 STAGE1_FLAGS ?=
 ifeq ($(DYNLINK),1)
     ifeq ($(ARCH),riscv)
         # TODO: implement dynamic linking for RISC-V.
         $(error "Dynamic linking mode is not implemented for RISC-V")
     endif
-    BUILTIN_LIBC := c.h
     STAGE0_FLAGS += --dynlink
     STAGE1_FLAGS += --dynlink
 endif
@@ -135,11 +135,12 @@ $(OUT)/norm-lf: tools/norm-lf.c
 	$(VECHO) "  CC+LD\t$@\n"
 	$(Q)$(CC) $(CFLAGS) -o $@ $^
 
-$(OUT)/libc.inc: $(OUT)/inliner $(OUT)/norm-lf $(LIBDIR)/$(BUILTIN_LIBC)
+$(OUT)/libc.inc: $(OUT)/inliner $(OUT)/norm-lf $(LIBDIR)/$(BUILTIN_LIBC_SOURCE) $(LIBDIR)/$(BUILTIN_LIBC_HEADER)
 	$(VECHO) "  GEN\t$@\n"
-	$(Q)$(OUT)/norm-lf $(LIBDIR)/$(BUILTIN_LIBC) $(OUT)/c.normalized.c
-	$(Q)$(OUT)/inliner $(OUT)/c.normalized.c $@
-	$(Q)$(RM) $(OUT)/c.normalized.c
+	$(Q)$(OUT)/norm-lf $(LIBDIR)/$(BUILTIN_LIBC_SOURCE) $(OUT)/c.normalized.c
+	$(Q)$(OUT)/norm-lf $(LIBDIR)/$(BUILTIN_LIBC_HEADER) $(OUT)/c.normalized.h
+	$(Q)$(OUT)/inliner $(OUT)/c.normalized.c $(OUT)/c.normalized.h $@
+	$(Q)$(RM) $(OUT)/c.normalized.c $(OUT)/c.normalized.h
 
 $(OUT)/inliner: tools/inliner.c
 	$(VECHO) "  CC+LD\t$@\n"

lib/c.c

@@ -6,50 +6,9 @@
  */
 
 /* minimal libc implementation */
-
-#define NULL 0
-
-#define bool _Bool
-#define true 1
-#define false 0
-
-#define INT_MAX 0x7fffffff
-#define INT_MIN 0x80000000
-
-#if defined(__arm__)
-#define __SIZEOF_POINTER__ 4
-#define __syscall_exit 1
-#define __syscall_read 3
-#define __syscall_write 4
-#define __syscall_close 6
-#define __syscall_open 5
-#define __syscall_mmap2 192
-#define __syscall_munmap 91
-
-#elif defined(__riscv)
-#define __SIZEOF_POINTER__ 4
-#define __syscall_exit 93
-#define __syscall_read 63
-#define __syscall_write 64
-#define __syscall_close 57
-#define __syscall_open 1024
-#define __syscall_openat 56
-#define __syscall_mmap2 222
-#define __syscall_munmap 215
-
-#else /* Only Arm32 and RV32 are supported */
-#error "Unsupported architecture"
-#endif
-
+#include "c.h"
 #define INT_BUF_LEN 16
 
-typedef int FILE;
-
-/* va_list support for variadic functions */
-typedef int *va_list;
-
-void abort(void);
-
 int strlen(char *str)
 {
     /* process the string by checking 4 characters (a 32-bit word) at a time */
@@ -584,18 +543,11 @@ int fputc(int c, FILE *stream)
     return c;
 }
 
-/* Non-portable: Assume page size is 4KiB */
-#define PAGESIZE 4096
-
 #define CHUNK_SIZE_FREED_MASK 1
 #define CHUNK_SIZE_SZ_MASK 0xFFFFFFFE
 #define CHUNK_GET_SIZE(size) (size & CHUNK_SIZE_SZ_MASK)
 #define IS_CHUNK_GET_FREED(size) (size & CHUNK_SIZE_FREED_MASK)
 
-/* Minimum alignment for all memory allocations. */
-#define MIN_ALIGNMENT 8
-#define ALIGN_UP(val, align) (((val) + (align) - 1) & ~((align) - 1))
-
 typedef struct chunk {
     struct chunk *next, *prev;
     int size;

lib/c.h

@@ -14,6 +14,41 @@
 #define true 1
 #define false 0
 
+#define INT_MAX 0x7fffffff
+#define INT_MIN 0x80000000
+
+#if defined(__arm__)
+#define __SIZEOF_POINTER__ 4
+#define __syscall_exit 1
+#define __syscall_read 3
+#define __syscall_write 4
+#define __syscall_close 6
+#define __syscall_open 5
+#define __syscall_mmap2 192
+#define __syscall_munmap 91
+
+#elif defined(__riscv)
+#define __SIZEOF_POINTER__ 4
+#define __syscall_exit 93
+#define __syscall_read 63
+#define __syscall_write 64
+#define __syscall_close 57
+#define __syscall_open 1024
+#define __syscall_openat 56
+#define __syscall_mmap2 222
+#define __syscall_munmap 215
+
+#else /* Only Arm32 and RV32 are supported */
+#error "Unsupported architecture"
+#endif
+
+/* Non-portable: Assume page size is 4KiB */
+#define PAGESIZE 4096
+
+/* Minimum alignment for all memory allocations. */
+#define MIN_ALIGNMENT 8
+#define ALIGN_UP(val, align) (((val) + (align) - 1) & ~((align) - 1))
+
 /* va_list support for variadic functions */
 typedef int *va_list;
 

src/main.c

@@ -86,8 +86,11 @@ int main(int argc, char *argv[])
     global_init();
 
     /* include libc */
-    if (libc)
-        libc_generate();
+    if (libc) {
+        libc_decl();
+        if (!dynlink)
+            libc_impl();
+    }
 
     /* load and parse source code into IR */
     parse(in);

tools/inliner.c

@@ -138,6 +138,12 @@ void load_from(char *file)
             fclose(f);
             return;
         }
+
+        if (!strncmp(buffer, "#pragma once", 12))
+            continue;
+        if (!strncmp(buffer, "#include \"c.h\"", 14))
+            continue;
+
         write_line(buffer);
     }
     fclose(f);
@@ -153,8 +159,8 @@ void save_to(char *file)
 
 int main(int argc, char *argv[])
 {
-    if (argc <= 2) {
-        printf("Usage: inliner <input.c> <output.inc>\n");
+    if (argc <= 3) {
+        printf("Usage: inliner <input.c> <input.h> <output.inc>\n");
         return -1;
     }
 
@@ -176,10 +182,15 @@ int main(int argc, char *argv[])
     write_str("    strbuf_puts(SOURCE, src);\n");
     write_str("}\n");
 
-    write_str("void libc_generate() {\n");
+    write_str("void libc_impl() {\n");
     load_from(argv[1]);
     write_str("}\n");
-    save_to(argv[2]);
+
+    write_str("void libc_decl() {\n");
+    load_from(argv[2]);
+    write_str("}\n");
+
+    save_to(argv[3]);
     strbuf_free(SOURCE);
 
     return 0;