Add initial files.

This populates the repo with a very minimal set of files. This is just
enough to set out a basic outline. Hopefully as we move forward we'll
be replacing many of these parts, but this is just something basic to
get things started.

This tree isn't really usable yet, as it doesn't yet have an easy way
to obtain a compiler-rt/libgcc build.

Author: sunfishcode

.gitignore

@@ -0,0 +1 @@
+sysroot

LICENSE

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+Please see the LICENSE file in each top-level directory for the terms applicable to that directory and its relative sub-directories.
+
+The relevant directories and licenses are:
+
+basics/      - CC0 1.0 Universal (CC0 1.0) Public Domain Dedication

Makefile

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+# These variables are specifically meant to be overridable via
+# the make command-line.
+WASM_CC = clang
+WASM_CFLAGS = -O2
+WASM_TARGET_FLAGS = --target=wasm32
+SYSROOT = sysroot
+
+# These variables describe the locations of various files and
+# directories in the source tree.
+BASICS_DIR = basics
+BASICS_INC = basics/include
+BASICS_LIBC_DIR = $(BASICS_DIR)/libc
+BASICS_LIBC_SOURCES = $(BASICS_LIBC_DIR)/string.c
+
+.PHONY: $(SYSROOT)
+$(SYSROOT):
+	$(RM) -r "$(SYSROOT)"
+	mkdir -p "$(SYSROOT)/usr"
+
+	#
+	# Install the include files.
+	#
+	cp -r  "$(BASICS_INC)" "$(SYSROOT)/usr"
+
+	#
+	# Build the C startup files.
+	#
+	$(RM) *.o
+	"$(WASM_CC)" $(WASM_CFLAGS) $(WASM_TARGET_FLAGS) --sysroot="$(SYSROOT)" -c $(BASICS_LIBC_DIR)/crt*.s
+	mkdir -p "$(SYSROOT)/lib"
+	mv *.o "$(SYSROOT)/lib"
+
+	#
+	# Compile and install the libc-subset source files.
+	#
+	$(RM) *.o
+	"$(WASM_CC)" $(WASM_CFLAGS) $(WASM_TARGET_FLAGS) --sysroot="$(SYSROOT)" -c $(BASICS_LIBC_SOURCES)
+	mkdir -p "$(SYSROOT)/lib"
+	ar crs "$(SYSROOT)/lib/libc.a" *.o
+	$(RM) *.o

README.md

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+# WebAssembly Reference Sysroot
+
+Caution: This is currently quite experimental and not generally usable yet!
+
+## What is this?
+
+This is a "reference sysroot", which is meant to be part of a common C ABI
+that can be shared across C libraries and compilers. While it's intened to
+(eventually) be usable in its own right, we fully expect other
+implementations to be used in practice by many different systems, though
+we do hope that in those cases, this library defines a useful ABI that can
+be followed.
+
+## Usage
+
+Obtain a WebAssembly-supporting C compiler, and then run:
+
+```
+make WASM_CC=/path/to/wasm/supporting/c/compiler
+```
+
+This makes a directory called "sysroot", by default. See the top of the Makfile
+for customization options.
+
+To use the sysroot, use the `--sysroot=` option:
+
+```
+/path/to/wasm/supporting/c/compiler --sysroot=/path/to/the/newly/built/sysroot ...
+``
+
+to run the compiler using the newly built sysroot.

basics/LICENSE

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+Creative Commons Legal Code
+
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+
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+Rights in the Work or (ii) assert any associated claims and causes of
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+4. Limitations and Disclaimers.
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+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
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basics/include/__typedef_clock_t.h

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+/* Define this as a 64-bit signed integer to avoid wraparounds. */
+typedef long long clock_t;

basics/include/__typedef_time_t.h

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+/* Define this as a 64-bit signed integer to avoid the 2038 bug. */
+typedef long long time_t;

basics/include/stdlib.h

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+#ifndef __wasm_sysroot_stdlib_h
+#define __wasm_sysroot_stdlib_h
+
+#define __need_size_t
+#define __need_wchar_t
+#define __need_NULL
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void *malloc(size_t size);
+void free(void *ptr);
+void *calloc(size_t nmemb, size_t size);
+void *realloc(void *ptr, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

basics/include/string.h

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+#ifndef __wasm_sysroot_string_h
+#define __wasm_sysroot_string_h
+
+#define __need_size_t
+#define __need_NULL
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void *memcpy(void *dst, const void *src, size_t n);
+void *memmove(void *dst, const void *src, size_t n);
+void *memset(void *dst, int c, size_t n);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

basics/include/sys/types.h

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+#ifndef __wasm_sysroot_sys_types_h
+#define __wasm_sysroot_sys_types_h
+
+#define __need_size_t
+#include <stddef.h>
+
+#include <__typedef_clock_t.h>
+#include <__typedef_time_t.h>
+
+/* Define these as 64-bit signed integers to support files larger than 2 GiB. */
+typedef long long blksize_t;
+typedef long long off_t;
+
+/* This is defined to be the same size as size_t. */
+typedef long ssize_t;
+
+#endif