]> git.proxmox.com Git - wasi-libc.git/blobdiff - Makefile
feat: add support for accept and accept4
[wasi-libc.git] / Makefile
index 74482056ead8e6e90596941308ed3f464e000067..98aa995bc124269057925838a534e14f8d2e33e5 100644 (file)
--- a/Makefile
+++ b/Makefile
-# 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 are specifically meant to be overridable via the make
+# command-line.
+CC ?= clang
+NM ?= $(patsubst %clang,%llvm-nm,$(filter-out ccache sccache,$(CC)))
+AR ?= $(patsubst %clang,%llvm-ar,$(filter-out ccache sccache,$(CC)))
+EXTRA_CFLAGS ?= -O2 -DNDEBUG
+# The directory where we build the sysroot.
+SYSROOT ?= $(CURDIR)/sysroot
+# A directory to install to for "make install".
+INSTALL_DIR ?= /usr/local
+# single or posix
+THREAD_MODEL ?= single
+# dlmalloc or none
+MALLOC_IMPL ?= dlmalloc
+# yes or no
+BUILD_LIBC_TOP_HALF ?= yes
+# The directory where we're store intermediate artifacts.
+OBJDIR ?= $(CURDIR)/build
+
+# Variables from this point on are not meant to be overridable via the
+# make command-line.
+
+# Set the target variables. Multiarch triples notably omit the vendor field,
+# which happens to be what we do for the main target triple too.
+TARGET_TRIPLE = wasm32-wasi
+MULTIARCH_TRIPLE = wasm32-wasi
+
+# These variables describe the locations of various files and directories in
+# the source tree.
+DLMALLOC_DIR = $(CURDIR)/dlmalloc
+DLMALLOC_SRC_DIR = $(DLMALLOC_DIR)/src
+DLMALLOC_SOURCES = $(DLMALLOC_SRC_DIR)/dlmalloc.c
+DLMALLOC_INC = $(DLMALLOC_DIR)/include
+LIBC_BOTTOM_HALF_DIR = $(CURDIR)/libc-bottom-half
+LIBC_BOTTOM_HALF_CLOUDLIBC_SRC = $(LIBC_BOTTOM_HALF_DIR)/cloudlibc/src
+LIBC_BOTTOM_HALF_CLOUDLIBC_SRC_INC = $(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC)/include
+LIBC_BOTTOM_HALF_HEADERS_PUBLIC = $(LIBC_BOTTOM_HALF_DIR)/headers/public
+LIBC_BOTTOM_HALF_HEADERS_PRIVATE = $(LIBC_BOTTOM_HALF_DIR)/headers/private
+LIBC_BOTTOM_HALF_SOURCES = $(LIBC_BOTTOM_HALF_DIR)/sources
+LIBC_BOTTOM_HALF_ALL_SOURCES = \
+    $(shell find $(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC) -name \*.c) \
+    $(shell find $(LIBC_BOTTOM_HALF_SOURCES) -name \*.c)
+
+# 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
+# then we don't have to do this.
+LIBC_BOTTOM_HALF_ALL_SOURCES := $(filter-out $(LIBC_BOTTOM_HALF_SOURCES)/chdir.c,$(LIBC_BOTTOM_HALF_ALL_SOURCES))
+LIBC_BOTTOM_HALF_ALL_SOURCES := $(LIBC_BOTTOM_HALF_ALL_SOURCES) $(LIBC_BOTTOM_HALF_SOURCES)/chdir.c
+
+LIBWASI_EMULATED_MMAN_SOURCES = \
+    $(shell find $(LIBC_BOTTOM_HALF_DIR)/mman -name \*.c)
+LIBWASI_EMULATED_PROCESS_CLOCKS_SOURCES = \
+    $(shell find $(LIBC_BOTTOM_HALF_DIR)/clocks -name \*.c)
+LIBWASI_EMULATED_GETPID_SOURCES = \
+    $(shell find $(LIBC_BOTTOM_HALF_DIR)/getpid -name \*.c)
+LIBWASI_EMULATED_SIGNAL_SOURCES = \
+    $(shell find $(LIBC_BOTTOM_HALF_DIR)/signal -name \*.c)
+LIBWASI_EMULATED_SIGNAL_MUSL_SOURCES = \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/signal/psignal.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/string/strsignal.c
+LIBC_BOTTOM_HALF_CRT_SOURCES = $(wildcard $(LIBC_BOTTOM_HALF_DIR)/crt/*.c)
+LIBC_TOP_HALF_DIR = $(CURDIR)/libc-top-half
+LIBC_TOP_HALF_MUSL_DIR = $(LIBC_TOP_HALF_DIR)/musl
+LIBC_TOP_HALF_MUSL_SRC_DIR = $(LIBC_TOP_HALF_MUSL_DIR)/src
+LIBC_TOP_HALF_MUSL_INC = $(LIBC_TOP_HALF_MUSL_DIR)/include
+LIBC_TOP_HALF_MUSL_SOURCES = \
+    $(addprefix $(LIBC_TOP_HALF_MUSL_SRC_DIR)/, \
+        misc/a64l.c \
+        misc/basename.c \
+        misc/dirname.c \
+        misc/ffs.c \
+        misc/ffsl.c \
+        misc/ffsll.c \
+        misc/fmtmsg.c \
+        misc/getdomainname.c \
+        misc/gethostid.c \
+        misc/getopt.c \
+        misc/getopt_long.c \
+        misc/getsubopt.c \
+        misc/uname.c \
+        misc/nftw.c \
+        errno/strerror.c \
+        network/htonl.c \
+        network/htons.c \
+        network/ntohl.c \
+        network/ntohs.c \
+        network/inet_ntop.c \
+        network/inet_pton.c \
+        network/inet_aton.c \
+        network/in6addr_any.c \
+        network/in6addr_loopback.c \
+        fenv/fenv.c \
+        fenv/fesetround.c \
+        fenv/feupdateenv.c \
+        fenv/fesetexceptflag.c \
+        fenv/fegetexceptflag.c \
+        fenv/feholdexcept.c \
+        exit/exit.c \
+        exit/atexit.c \
+        exit/assert.c \
+        exit/quick_exit.c \
+        exit/at_quick_exit.c \
+        time/strftime.c \
+        time/asctime.c \
+        time/asctime_r.c \
+        time/ctime.c \
+        time/ctime_r.c \
+        time/wcsftime.c \
+        time/strptime.c \
+        time/difftime.c \
+        time/timegm.c \
+        time/ftime.c \
+        time/gmtime.c \
+        time/gmtime_r.c \
+        time/timespec_get.c \
+        time/getdate.c \
+        time/localtime.c \
+        time/localtime_r.c \
+        time/mktime.c \
+        time/__tm_to_secs.c \
+        time/__month_to_secs.c \
+        time/__secs_to_tm.c \
+        time/__year_to_secs.c \
+        time/__tz.c \
+        fcntl/creat.c \
+        dirent/alphasort.c \
+        dirent/versionsort.c \
+        env/clearenv.c \
+        env/getenv.c \
+        env/putenv.c \
+        env/setenv.c \
+        env/unsetenv.c \
+        unistd/posix_close.c \
+        stat/futimesat.c \
+    ) \
+    $(filter-out %/procfdname.c %/syscall.c %/syscall_ret.c %/vdso.c %/version.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/internal/*.c)) \
+    $(filter-out %/flockfile.c %/funlockfile.c %/__lockfile.c %/ftrylockfile.c \
+                 %/rename.c \
+                 %/tmpnam.c %/tmpfile.c %/tempnam.c \
+                 %/popen.c %/pclose.c \
+                 %/remove.c \
+                 %/gets.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdio/*.c)) \
+    $(filter-out %/strsignal.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/string/*.c)) \
+    $(filter-out %/dcngettext.c %/textdomain.c %/bind_textdomain_codeset.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/locale/*.c)) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdlib/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/search/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/multibyte/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/regex/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/prng/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/conf/*.c) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/ctype/*.c) \
+    $(filter-out %/__signbit.c %/__signbitf.c %/__signbitl.c \
+                 %/__fpclassify.c %/__fpclassifyf.c %/__fpclassifyl.c \
+                 %/ceilf.c %/ceil.c \
+                 %/floorf.c %/floor.c \
+                 %/truncf.c %/trunc.c \
+                 %/rintf.c %/rint.c \
+                 %/nearbyintf.c %/nearbyint.c \
+                 %/sqrtf.c %/sqrt.c \
+                 %/fabsf.c %/fabs.c \
+                 %/copysignf.c %/copysign.c \
+                 %/fminf.c %/fmaxf.c \
+                 %/fmin.c %/fmax.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/math/*.c)) \
+    $(filter-out %/crealf.c %/creal.c %creall.c \
+                 %/cimagf.c %/cimag.c %cimagl.c, \
+                 $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/complex/*.c)) \
+    $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/crypt/*.c)
+MUSL_PRINTSCAN_SOURCES = \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/internal/floatscan.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdio/vfprintf.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdio/vfwprintf.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdio/vfscanf.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdlib/strtod.c \
+    $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdlib/wcstod.c
+LIBC_TOP_HALF_HEADERS_PRIVATE = $(LIBC_TOP_HALF_DIR)/headers/private
+LIBC_TOP_HALF_SOURCES = $(LIBC_TOP_HALF_DIR)/sources
+LIBC_TOP_HALF_ALL_SOURCES = \
+    $(LIBC_TOP_HALF_MUSL_SOURCES) \
+    $(shell find $(LIBC_TOP_HALF_SOURCES) -name \*.c)
+
+# Add any extra flags
+CFLAGS = $(EXTRA_CFLAGS)
+# Set the target.
+CFLAGS += --target=$(TARGET_TRIPLE)
+# WebAssembly floating-point match doesn't trap.
+# TODO: Add -fno-signaling-nans when the compiler supports it.
+CFLAGS += -fno-trapping-math
+# Add all warnings, but disable a few which occur in third-party code.
+CFLAGS += -Wall -Wextra -Werror \
+  -Wno-null-pointer-arithmetic \
+  -Wno-unused-parameter \
+  -Wno-sign-compare \
+  -Wno-unused-variable \
+  -Wno-unused-function \
+  -Wno-ignored-attributes \
+  -Wno-missing-braces \
+  -Wno-ignored-pragmas \
+  -Wno-unused-but-set-variable \
+  -Wno-unknown-warning-option
+
+# Configure support for threads.
+ifeq ($(THREAD_MODEL), single)
+CFLAGS += -mthread-model single
+endif
+ifeq ($(THREAD_MODEL), posix)
+CFLAGS += -mthread-model posix -pthread
+endif
+
+# Expose the public headers to the implementation. We use `-isystem` for
+# purpose for two reasons:
+#
+# 1. It only does `<...>` not `"...."` lookup. We are making a libc,
+#    which is a system library, so all public headers should be
+#    accessible via `<...>` and never also need `"..."`. `-isystem` main
+#    purpose is to only effect `<...>` lookup.
+#
+# 2. The `-I` for private headers added for specific C files below
+#    should come earlier in the search path, so they can "override"
+#    and/or `#include_next` the public headers. `-isystem` (like
+#    `-idirafter`) comes later in the search path than `-I`.
+CFLAGS += -isystem "$(SYSROOT_INC)"
+
+# These variables describe the locations of various files and directories in
+# the build tree.
+objs = $(patsubst $(CURDIR)/%.c,$(OBJDIR)/%.o,$(1))
+DLMALLOC_OBJS = $(call objs,$(DLMALLOC_SOURCES))
+LIBC_BOTTOM_HALF_ALL_OBJS = $(call objs,$(LIBC_BOTTOM_HALF_ALL_SOURCES))
+LIBC_TOP_HALF_ALL_OBJS = $(call objs,$(LIBC_TOP_HALF_ALL_SOURCES))
+ifeq ($(MALLOC_IMPL),dlmalloc)
+LIBC_OBJS += $(DLMALLOC_OBJS)
+else ifeq ($(MALLOC_IMPL),none)
+# No object files to add.
+else
+$(error unknown malloc implementation $(MALLOC_IMPL))
+endif
+# Add libc-bottom-half's objects.
+LIBC_OBJS += $(LIBC_BOTTOM_HALF_ALL_OBJS)
+ifeq ($(BUILD_LIBC_TOP_HALF),yes)
+# libc-top-half is musl.
+LIBC_OBJS += $(LIBC_TOP_HALF_ALL_OBJS)
+endif
+MUSL_PRINTSCAN_OBJS = $(call objs,$(MUSL_PRINTSCAN_SOURCES))
+MUSL_PRINTSCAN_LONG_DOUBLE_OBJS = $(patsubst %.o,%.long-double.o,$(MUSL_PRINTSCAN_OBJS))
+MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS = $(patsubst %.o,%.no-floating-point.o,$(MUSL_PRINTSCAN_OBJS))
+LIBWASI_EMULATED_MMAN_OBJS = $(call objs,$(LIBWASI_EMULATED_MMAN_SOURCES))
+LIBWASI_EMULATED_PROCESS_CLOCKS_OBJS = $(call objs,$(LIBWASI_EMULATED_PROCESS_CLOCKS_SOURCES))
+LIBWASI_EMULATED_GETPID_OBJS = $(call objs,$(LIBWASI_EMULATED_GETPID_SOURCES))
+LIBWASI_EMULATED_SIGNAL_OBJS = $(call objs,$(LIBWASI_EMULATED_SIGNAL_SOURCES))
+LIBWASI_EMULATED_SIGNAL_MUSL_OBJS = $(call objs,$(LIBWASI_EMULATED_SIGNAL_MUSL_SOURCES))
 
 # 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"
+# directories in the generated sysroot tree.
+SYSROOT_LIB := $(SYSROOT)/lib/$(MULTIARCH_TRIPLE)
+SYSROOT_INC = $(SYSROOT)/include
+SYSROOT_SHARE = $(SYSROOT)/share/$(MULTIARCH_TRIPLE)
+
+# Files from musl's include directory that we don't want to install in the
+# sysroot's include directory.
+MUSL_OMIT_HEADERS :=
+
+# Remove files which aren't headers (we generate alltypes.h below).
+MUSL_OMIT_HEADERS += \
+    "bits/syscall.h.in" \
+    "bits/alltypes.h.in" \
+    "alltypes.h.in"
+
+# Use the compiler's version of these headers.
+MUSL_OMIT_HEADERS += \
+    "stdarg.h" \
+    "stddef.h"
+
+# Use the WASI errno definitions.
+MUSL_OMIT_HEADERS += \
+    "bits/errno.h"
+
+# Remove headers that aren't supported yet or that aren't relevant for WASI.
+MUSL_OMIT_HEADERS += \
+    "sys/procfs.h" \
+    "sys/user.h" \
+    "sys/kd.h" "sys/vt.h" "sys/soundcard.h" "sys/sem.h" \
+    "sys/shm.h" "sys/msg.h" "sys/ipc.h" "sys/ptrace.h" \
+    "sys/statfs.h" \
+    "bits/kd.h" "bits/vt.h" "bits/soundcard.h" "bits/sem.h" \
+    "bits/shm.h" "bits/msg.h" "bits/ipc.h" "bits/ptrace.h" \
+    "bits/statfs.h" \
+    "sys/vfs.h" \
+    "sys/statvfs.h" \
+    "syslog.h" "sys/syslog.h" \
+    "wait.h" "sys/wait.h" \
+    "ucontext.h" "sys/ucontext.h" \
+    "paths.h" \
+    "utmp.h" "utmpx.h" \
+    "lastlog.h" \
+    "sys/acct.h" \
+    "sys/cachectl.h" \
+    "sys/epoll.h" "sys/reboot.h" "sys/swap.h" \
+    "sys/sendfile.h" "sys/inotify.h" \
+    "sys/quota.h" \
+    "sys/klog.h" \
+    "sys/fsuid.h" \
+    "sys/io.h" \
+    "sys/prctl.h" \
+    "sys/mtio.h" \
+    "sys/mount.h" \
+    "sys/fanotify.h" \
+    "sys/personality.h" \
+    "elf.h" "link.h" "bits/link.h" \
+    "scsi/scsi.h" "scsi/scsi_ioctl.h" "scsi/sg.h" \
+    "sys/auxv.h" \
+    "pwd.h" "shadow.h" "grp.h" \
+    "mntent.h" \
+    "netdb.h" \
+    "resolv.h" \
+    "pty.h" \
+    "dlfcn.h" \
+    "setjmp.h" \
+    "ulimit.h" \
+    "sys/xattr.h" \
+    "wordexp.h" \
+    "spawn.h" \
+    "sys/membarrier.h" \
+    "sys/signalfd.h" \
+    "termios.h" \
+    "sys/termios.h" \
+    "bits/termios.h" \
+    "net/if.h" \
+    "net/if_arp.h" \
+    "net/ethernet.h" \
+    "net/route.h" \
+    "netinet/if_ether.h" \
+    "netinet/ether.h" \
+    "sys/timerfd.h" \
+    "libintl.h" \
+    "sys/sysmacros.h"
+
+ifeq ($(THREAD_MODEL), single)
+# Remove headers not supported in single-threaded mode.
+MUSL_OMIT_HEADERS += "aio.h" "pthread.h"
+endif
+
+default: finish
+
+$(SYSROOT_LIB)/libc.a: $(LIBC_OBJS)
+
+$(SYSROOT_LIB)/libc-printscan-long-double.a: $(MUSL_PRINTSCAN_LONG_DOUBLE_OBJS)
+
+$(SYSROOT_LIB)/libc-printscan-no-floating-point.a: $(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS)
+
+$(SYSROOT_LIB)/libwasi-emulated-mman.a: $(LIBWASI_EMULATED_MMAN_OBJS)
+
+$(SYSROOT_LIB)/libwasi-emulated-process-clocks.a: $(LIBWASI_EMULATED_PROCESS_CLOCKS_OBJS)
+
+$(SYSROOT_LIB)/libwasi-emulated-getpid.a: $(LIBWASI_EMULATED_GETPID_OBJS)
+
+$(SYSROOT_LIB)/libwasi-emulated-signal.a: $(LIBWASI_EMULATED_SIGNAL_OBJS) $(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS)
+
+%.a:
+       @mkdir -p "$(@D)"
+       # On Windows, the commandline for the ar invocation got too long, so it needs to be split up.
+       $(AR) crs $@ $(wordlist 1, 199, $^)
+       $(AR) crs $@ $(wordlist 200, 399, $^)
+       $(AR) crs $@ $(wordlist 400, 599, $^)
+       $(AR) crs $@ $(wordlist 600, 799, $^)
+       # This might eventually overflow again, but at least it'll do so in a loud way instead of
+       # silently dropping the tail.
+       $(AR) crs $@ $(wordlist 800, 100000, $^)
+
+$(MUSL_PRINTSCAN_OBJS): CFLAGS += \
+           -D__wasilibc_printscan_no_long_double \
+           -D__wasilibc_printscan_full_support_option="\"add -lc-printscan-long-double to the link command\""
+
+$(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS): CFLAGS += \
+           -D__wasilibc_printscan_no_floating_point \
+           -D__wasilibc_printscan_floating_point_support_option="\"remove -lc-printscan-no-floating-point from the link command\""
+
+$(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): CFLAGS += \
+           -D_WASI_EMULATED_SIGNAL
+
+$(OBJDIR)/%.long-double.o: $(CURDIR)/%.c include_dirs
+       @mkdir -p "$(@D)"
+       $(CC) $(CFLAGS) -MD -MP -o $@ -c $<
+
+$(OBJDIR)/%.no-floating-point.o: $(CURDIR)/%.c include_dirs
+       @mkdir -p "$(@D)"
+       $(CC) $(CFLAGS) -MD -MP -o $@ -c $<
+
+$(OBJDIR)/%.o: $(CURDIR)/%.c include_dirs
+       @mkdir -p "$(@D)"
+       $(CC) $(CFLAGS) -MD -MP -o $@ -c $<
+
+-include $(shell find $(OBJDIR) -name \*.d)
+
+$(DLMALLOC_OBJS): CFLAGS += \
+    -I$(DLMALLOC_INC)
 
+startup_files $(LIBC_BOTTOM_HALF_ALL_OBJS): CFLAGS += \
+    -I$(LIBC_BOTTOM_HALF_HEADERS_PRIVATE) \
+    -I$(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC_INC) \
+    -I$(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC)
+
+$(LIBC_TOP_HALF_ALL_OBJS) $(MUSL_PRINTSCAN_LONG_DOUBLE_OBJS) $(MUSL_PRINTSCAN_NO_FLOATING_POINT_OBJS) $(LIBWASI_EMULATED_SIGNAL_MUSL_OBJS): CFLAGS += \
+    -I$(LIBC_TOP_HALF_MUSL_SRC_DIR)/include \
+    -I$(LIBC_TOP_HALF_MUSL_SRC_DIR)/internal \
+    -I$(LIBC_TOP_HALF_MUSL_DIR)/arch/wasm32 \
+    -I$(LIBC_TOP_HALF_MUSL_DIR)/arch/generic \
+    -I$(LIBC_TOP_HALF_HEADERS_PRIVATE) \
+    -Wno-parentheses \
+    -Wno-shift-op-parentheses \
+    -Wno-bitwise-op-parentheses \
+    -Wno-logical-op-parentheses \
+    -Wno-string-plus-int \
+    -Wno-dangling-else \
+    -Wno-unknown-pragmas
+
+$(LIBWASI_EMULATED_PROCESS_CLOCKS_OBJS): CFLAGS += \
+    -I$(LIBC_BOTTOM_HALF_CLOUDLIBC_SRC)
+
+include_dirs:
        #
        # Install the include files.
        #
-       cp -r  "$(BASICS_INC)" "$(SYSROOT)/usr"
+       mkdir -p "$(SYSROOT_INC)"
+       cp -r "$(LIBC_BOTTOM_HALF_HEADERS_PUBLIC)"/* "$(SYSROOT_INC)"
+
+       # Generate musl's bits/alltypes.h header.
+       mkdir -p "$(SYSROOT_INC)/bits"
+       sed -f $(LIBC_TOP_HALF_MUSL_DIR)/tools/mkalltypes.sed \
+           $(LIBC_TOP_HALF_MUSL_DIR)/arch/wasm32/bits/alltypes.h.in \
+           $(LIBC_TOP_HALF_MUSL_DIR)/include/alltypes.h.in \
+           > "$(SYSROOT_INC)/bits/alltypes.h"
+
+       # Copy in the bulk of musl's public header files.
+       cp -r "$(LIBC_TOP_HALF_MUSL_INC)"/* "$(SYSROOT_INC)"
+       # Copy in the musl's "bits" header files.
+       cp -r "$(LIBC_TOP_HALF_MUSL_DIR)"/arch/generic/bits/* "$(SYSROOT_INC)/bits"
+       cp -r "$(LIBC_TOP_HALF_MUSL_DIR)"/arch/wasm32/bits/* "$(SYSROOT_INC)/bits"
+
+       # Remove selected header files.
+       $(RM) $(patsubst %,$(SYSROOT_INC)/%,$(MUSL_OMIT_HEADERS))
+
+startup_files: include_dirs
+       #
+       # Build the startup files.
+       #
+       @mkdir -p "$(OBJDIR)"
+       cd "$(OBJDIR)" && \
+       $(CC) $(CFLAGS) -c $(LIBC_BOTTOM_HALF_CRT_SOURCES) -MD -MP && \
+       mkdir -p "$(SYSROOT_LIB)" && \
+       mv *.o "$(SYSROOT_LIB)"
+
+libc: include_dirs \
+    $(SYSROOT_LIB)/libc.a \
+    $(SYSROOT_LIB)/libc-printscan-long-double.a \
+    $(SYSROOT_LIB)/libc-printscan-no-floating-point.a \
+    $(SYSROOT_LIB)/libwasi-emulated-mman.a \
+    $(SYSROOT_LIB)/libwasi-emulated-process-clocks.a \
+    $(SYSROOT_LIB)/libwasi-emulated-getpid.a \
+    $(SYSROOT_LIB)/libwasi-emulated-signal.a
+
+finish: startup_files libc
+       #
+       # Create empty placeholder libraries.
+       #
+       for name in m rt pthread crypt util xnet resolv dl; do \
+           $(AR) crs "$(SYSROOT_LIB)/lib$${name}.a"; \
+       done
+
+       #
+       # The build succeeded! The generated sysroot is in $(SYSROOT).
+       #
+
+# The check for defined and undefined symbols expects there to be a heap
+# alloctor (providing malloc, calloc, free, etc). Skip this step if the build
+# is done without a malloc implementation.
+ifneq ($(MALLOC_IMPL),none)
+finish: check-symbols
+endif
+
+DEFINED_SYMBOLS = $(SYSROOT_SHARE)/defined-symbols.txt
+UNDEFINED_SYMBOLS = $(SYSROOT_SHARE)/undefined-symbols.txt
+
+check-symbols: startup_files libc
+       #
+       # Collect metadata on the sysroot and perform sanity checks.
+       #
+       mkdir -p "$(SYSROOT_SHARE)"
+
+       #
+       # Collect symbol information.
+       #
+       @# TODO: Use llvm-nm --extern-only instead of grep. This is blocked on
+       @# LLVM PR40497, which is fixed in 9.0, but not in 8.0.
+       @# Ignore certain llvm builtin symbols such as those starting with __mul
+       @# since these dependencies can vary between llvm versions.
+       "$(NM)" --defined-only "$(SYSROOT_LIB)"/libc.a "$(SYSROOT_LIB)"/libwasi-emulated-*.a "$(SYSROOT_LIB)"/*.o \
+           |grep ' [[:upper:]] ' |sed 's/.* [[:upper:]] //' |LC_ALL=C sort > "$(DEFINED_SYMBOLS)"
+       for undef_sym in $$("$(NM)" --undefined-only "$(SYSROOT_LIB)"/libc.a "$(SYSROOT_LIB)"/libc-*.a "$(SYSROOT_LIB)"/*.o \
+           |grep ' U ' |sed 's/.* U //' |LC_ALL=C sort |uniq); do \
+           grep -q '\<'$$undef_sym'\>' "$(DEFINED_SYMBOLS)" || echo $$undef_sym; \
+       done | grep -v "^__mul" > "$(UNDEFINED_SYMBOLS)"
+       grep '^_*imported_wasi_' "$(UNDEFINED_SYMBOLS)" \
+           > "$(SYSROOT_LIB)/libc.imports"
 
        #
-       # Build the C startup files.
+       # Generate a test file that includes all public header files.
        #
-       $(RM) *.o
-       "$(WASM_CC)" $(WASM_CFLAGS) $(WASM_TARGET_FLAGS) --sysroot="$(SYSROOT)" -c $(BASICS_LIBC_DIR)/crt*.s
-       mkdir -p "$(SYSROOT)/lib"
-       mv *.o "$(SYSROOT)/lib"
+       cd "$(SYSROOT_INC)" && \
+         for header in $$(find . -type f -not -name mman.h -not -name signal.h -not -name times.h -not -name resource.h |grep -v /bits/); do \
+             echo '#include <'$$header'>' | sed 's/\.\///' ; \
+       done |LC_ALL=C sort >$(SYSROOT_SHARE)/include-all.c ; \
+       cd - >/dev/null
 
        #
-       # Compile and install the libc-subset source files.
+       # Test that it compiles.
        #
-       $(RM) *.o
-       "$(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
+       $(CC) $(CFLAGS) -fsyntax-only "$(SYSROOT_SHARE)/include-all.c" -Wno-\#warnings
+
+       #
+       # Collect all the predefined macros, except for compiler version macros
+       # which we don't need to track here.
+       #
+       @#
+       @# For the __*_ATOMIC_*_LOCK_FREE macros, squash individual compiler names
+       @# to attempt, toward keeping these files compiler-independent.
+       @#
+       @# We have to add `-isystem $(SYSROOT_INC)` because otherwise clang puts
+       @# its builtin include path first, which produces compiler-specific
+       @# output.
+       @#
+       @# TODO: Undefine __FLOAT128__ for now since it's not in clang 8.0.
+       @# TODO: Filter out __FLT16_* for now, as not all versions of clang have these.
+       @# TODO: Filter out __NO_MATH_ERRNO_ and a few __*WIDTH__ that are new to clang 14.
+       @# TODO: clang defined __FLT_EVAL_METHOD__ until clang 15, so we force-undefine it
+       @# for older versions.
+       $(CC) $(CFLAGS) "$(SYSROOT_SHARE)/include-all.c" \
+           -isystem $(SYSROOT_INC) \
+           -std=gnu17 \
+           -E -dM -Wno-\#warnings \
+           -D_ALL_SOURCE \
+           -U__llvm__ \
+           -U__clang__ \
+           -U__clang_major__ \
+           -U__clang_minor__ \
+           -U__clang_patchlevel__ \
+           -U__clang_version__ \
+           -U__clang_literal_encoding__ \
+           -U__clang_wide_literal_encoding__ \
+           -U__GNUC__ \
+           -U__GNUC_MINOR__ \
+           -U__GNUC_PATCHLEVEL__ \
+           -U__VERSION__ \
+           -U__FLOAT128__ \
+           -U__NO_MATH_ERRNO__ \
+           -U__BITINT_MAXWIDTH__ \
+           -U__FLT_EVAL_METHOD__ -Wno-builtin-macro-redefined \
+           | sed -e 's/__[[:upper:][:digit:]]*_ATOMIC_\([[:upper:][:digit:]_]*\)_LOCK_FREE/__compiler_ATOMIC_\1_LOCK_FREE/' \
+           | grep -v '^#define __FLT16_' \
+           | grep -v '^#define __\(BOOL\|INT_\(LEAST\|FAST\)\(8\|16\|32\|64\)\|INT\|LONG\|LLONG\|SHRT\)_WIDTH__' \
+           > "$(SYSROOT_SHARE)/predefined-macros.txt"
+
+       # Check that the computed metadata matches the expected metadata.
+       # This ignores whitespace because on Windows the output has CRLF line endings.
+       diff -wur "$(CURDIR)/expected/$(MULTIARCH_TRIPLE)" "$(SYSROOT_SHARE)"
+
+install: finish
+       mkdir -p "$(INSTALL_DIR)"
+       cp -r "$(SYSROOT)/lib" "$(SYSROOT)/share" "$(SYSROOT)/include" "$(INSTALL_DIR)"
+
+clean:
+       $(RM) -r "$(OBJDIR)"
+       $(RM) -r "$(SYSROOT)"
+
+.PHONY: default startup_files libc finish install include_dirs clean