add WASI Preview 2 bindings

This adds C bindings generated from the `wasi:cli/[email protected]`
world, plus a makefile target to regenerate them from the WIT source files.

We'll use these bindings to call Preview 2 host functions when building for the
`wasm32-wasi-preview2` target.

Signed-off-by: Joel Dice <[email protected]>

Makefile

@@ -23,6 +23,12 @@ MALLOC_IMPL ?= dlmalloc
 BUILD_LIBC_TOP_HALF ?= yes
 # The directory where we will store intermediate artifacts.
 OBJDIR ?= build/$(TARGET_TRIPLE)
+# The directory where we store files and tools for generating WASI Preview 2 bindings
+BINDING_WORK_DIR ?= build/bindings
+# URL from which to retrieve the WIT files used to generate the WASI Preview 2 bindings
+WASI_CLI_URL ?= https://github.com/WebAssembly/wasi-cli/archive/refs/tags/v0.2.0-rc-2023-12-05.tar.gz
+# URL from which to retrieve the `wit-bindgen` command used to generate the WASI Preview 2 bindings
+WIT_BINDGEN_URL ?= https://github.com/bytecodealliance/wit-bindgen/releases/download/wit-bindgen-cli-0.16.0/wit-bindgen-v0.16.0-x86_64-linux.tar.gz
 
 # When the length is no larger than this threshold, we consider the
 # overhead of bulk memory opcodes to outweigh the performance benefit,
@@ -68,6 +74,19 @@ LIBC_BOTTOM_HALF_ALL_SOURCES = \
     $(shell find $(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC) -name \*.c) \
     $(shell find $(LIBC_BOTTOM_HALF_SOURCES) -name \*.c))
 
+ifeq ($(WASI_SNAPSHOT), preview1)
+# Omit source files not relevant to WASI Preview 1.  As we introduce files
+# supporting `wasi-sockets` for `wasm32-wasi-preview2`, we'll add those files to
+# this list.
+LIBC_BOTTOM_HALF_OMIT_SOURCES := \
+    $(addprefix $(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC)/libc/sys/, \
+        wasi/preview2.c \
+    )
+LIBC_BOTTOM_HALF_ALL_SOURCES := $(filter-out $(LIBC_BOTTOM_HALF_OMIT_SOURCES),$(LIBC_BOTTOM_HALF_ALL_SOURCES))
+# Omit preview2.h from include-all.c test.
+INCLUDE_ALL_CLAUSES := -not -name preview2.h
+endif
+
 # FIXME(https://reviews.llvm.org/D85567) - due to a bug in LLD the weak
 # references to a function defined in `chdir.c` only work if `chdir.c` is at the
 # end of the archive, but once that LLD review lands and propagates into LLVM
@@ -741,7 +760,7 @@ check-symbols: startup_files libc
 	# Generate a test file that includes all public C header files.
 	#
 	cd "$(SYSROOT_INC)" && \
-	  for header in $$(find . -type f -not -name mman.h -not -name signal.h -not -name times.h -not -name resource.h |grep -v /bits/ |grep -v /c++/); do \
+	  for header in $$(find . -type f -not -name mman.h -not -name signal.h -not -name times.h -not -name resource.h $(INCLUDE_ALL_CLAUSES) |grep -v /bits/ |grep -v /c++/); do \
 	      echo '#include <'$$header'>' | sed 's/\.\///' ; \
 	done |LC_ALL=C sort >$(SYSROOT_SHARE)/include-all.c ; \
 	cd - >/dev/null
@@ -816,8 +835,62 @@ install: finish
 	mkdir -p "$(INSTALL_DIR)"
 	cp -r "$(SYSROOT)/lib" "$(SYSROOT)/share" "$(SYSROOT)/include" "$(INSTALL_DIR)"
 
+$(BINDING_WORK_DIR)/wasi-cli:
+	mkdir -p "$(BINDING_WORK_DIR)"
+	cd "$(BINDING_WORK_DIR)" && \
+		curl -L "$(WASI_CLI_URL)" -o wasi-cli.tar.gz && \
+		tar xf wasi-cli.tar.gz && \
+		mv wasi-cli-* wasi-cli
+
+$(BINDING_WORK_DIR)/wit-bindgen:
+	mkdir -p "$(BINDING_WORK_DIR)"
+	cd "$(BINDING_WORK_DIR)" && \
+		curl -L "$(WIT_BINDGEN_URL)" -o wit-bindgen.tar.gz && \
+		tar xf wit-bindgen.tar.gz && \
+		mv wit-bindgen-* wit-bindgen
+
+bindings: $(BINDING_WORK_DIR)/wasi-cli $(BINDING_WORK_DIR)/wit-bindgen
+	cd "$(BINDING_WORK_DIR)" && \
+		./wit-bindgen/wit-bindgen c --world wasi:cli/[email protected] \
+			--rename wasi:clocks/[email protected]=monotonic_clock \
+			--rename wasi:clocks/[email protected]=wall_clock \
+			--rename wasi:filesystem/[email protected]=filesystem_preopens \
+			--rename wasi:filesystem/[email protected]=filesystem \
+			--rename wasi:io/[email protected]=io_error \
+			--rename wasi:io/[email protected]=poll \
+			--rename wasi:io/[email protected]=streams \
+			--rename wasi:random/[email protected]=random_insecure_seed \
+			--rename wasi:random/[email protected]=random_insecure \
+			--rename wasi:random/[email protected]=random \
+			--rename wasi:sockets/[email protected]=instance_network \
+			--rename wasi:sockets/[email protected]=ip_name_lookup \
+			--rename wasi:sockets/[email protected]=network \
+			--rename wasi:sockets/[email protected]=tcp_create_socket \
+			--rename wasi:sockets/[email protected]=tcp \
+			--rename wasi:sockets/[email protected]=udp_create_socket \
+			--rename wasi:sockets/[email protected]=udp \
+			--rename wasi:cli/[email protected]=environment \
+			--rename wasi:cli/[email protected]=exit \
+			--rename wasi:cli/[email protected]=stdin \
+			--rename wasi:cli/[email protected]=stdout \
+			--rename wasi:cli/[email protected]=stderr \
+			--rename wasi:cli/[email protected]=terminal_input \
+			--rename wasi:cli/[email protected]=terminal_output \
+			--rename wasi:cli/[email protected]=terminal_stdin \
+			--rename wasi:cli/[email protected]=terminal_stdout \
+			--rename wasi:cli/[email protected]=terminal_stderr \
+			./wasi-cli/wit && \
+		mv imports.h ../../libc-bottom-half/headers/public/wasi/preview2.h && \
+		sed 's_#include "imports.h"_#include "wasi/preview2.h"_' \
+			< imports.c \
+			> ../../libc-bottom-half/cloudlibc/src/libc/sys/wasi/preview2.c && \
+		rm imports.c && \
+		mv imports_component_type.o \
+			../../libc-bottom-half/cloudlibc/src/libc/sys/wasi/preview2_component_type.o
+
 clean:
+	$(RM) -r "$(BINDING_WORK_DIR)"
 	$(RM) -r "$(OBJDIR)"
 	$(RM) -r "$(SYSROOT)"
 
-.PHONY: default startup_files libc libc_so finish install include_dirs clean check-symbols
+.PHONY: default startup_files libc libc_so finish install include_dirs clean check-symbols bindings