Experiment Remove musl/libc dependency from RTS (#4577)

* Remove MUSL/LIBC dependency from RTS
* Update benchmark result

rts/Makefile

@@ -21,16 +21,7 @@ TOMMATHFILES = \
    s_mp_mul_digs_fast s_mp_mul_digs mp_init_multi mp_clear_multi mp_mul_2 mp_div_2 mp_div_3 mp_lshd mp_incr \
    mp_decr mp_add_d mp_sub_d
 
-MUSLFILES = \
-   pow_data exp_data log_data \
-   floor scalbn frexp strlen strnlen memcpy memset memchr memcmp \
-   __math_oflow __math_uflow __math_xflow __math_divzero __math_invalid \
-   __rem_pio2 __rem_pio2_large __sin __cos __tan \
-   stubs
-
 TOMMATHSRC ?= $(CURDIR)/../../libtommath
-MUSLSRC ?= $(CURDIR)/../../wasi-libc/libc-top-half/musl
-MUSL_WASI_SYSROOT ?= $(MUSLSRC)/../../sysroot
 
 #
 # Various libtommath flags, in particular telling it to use our own memory
@@ -52,49 +43,6 @@ TOMMATH_FLAGS = \
 # Note: the above __STDC_IEC_559__ define is somewhat of a misnomer
 #       as only IEEE 754 features are used.
 
-#
-# Various musl flags, in particular telling it to not have long doubles
-# and exclude <errno.h>, which pulls in too many dependencies
-#
-# Note: we use a bit of magic to get rid of invocations to __fwritex (and similar)
-#       - the headers contain a declaration, we rename it to (__fwritex ## __COUNTER__)
-#       - similarly the invocation becomes __fwritex_2(...) which we inline immediately
-#       Be aware that upon bumps of the musl sources the number of occurrences may jump a bit
-#       and will need tweaks/additions below.
-#       Similarly we define include guards (to suppress certain headers), but those should be
-#       pretty stable.
-#       TODO: run `wasm2wat --enable-memory64 mo-rts.wasm | grep -F '(import' | grep __fwritex_` expecting empty.
-#
-#       See also https://stackoverflow.com/questions/1597007/creating-c-macro-with-and-line-token-concatenation-with-positioning-macr
-
-# libc does not yet have a 64-bit port, using 32-bit version instead.
-MUSL_FLAGS = \
-  -isystem $(MUSLSRC)/arch/wasm32 \
-  -isystem $(MUSLSRC)/src/include \
-  -isystem $(MUSLSRC)/src/internal \
-  -isystem $(MUSL_WASI_SYSROOT)/include \
-  -I $(MUSLSRC)/../headers/private \
-  -I $(MUSLSRC)/src/include \
-  -D_ERRNO_H -DEOVERFLOW=75 -DEINVAL=22 \
-  -Derrno='(*({ static int bla = 0; &bla; }))' \
-  -DNL_ARGMAX=9 \
-  -D'TOKENPASTE0(x, y)=x \#\# y' \
-  -D'TOKENPASTE(x, y)=TOKENPASTE0(x, y)' \
-  -D'__fwritex=TOKENPASTE(__fwritex_,__COUNTER__)' \
-  -D'__fwritex_2(s, l, f)=(f->write((f), (s), (l)))' \
-  -D'__towrite=TOKENPASTE(__towrite_,__COUNTER__)' \
-  -D'__towrite_3(f)=(0)' \
-  -D__wasilibc_printscan_no_long_double \
-  -D__wasilibc_printscan_full_support_option='""' \
-  -D__wasi__ \
-  -D__NEED_va_list \
-  -D__NEED_off_t \
-  -D__NEED_locale_t \
-  -Dsqrt=__builtin_sqrt \
-  -Dfabs=__builtin_fabs \
-  -mbulk-memory \
-  -DBULK_MEMORY_THRESHOLD=32
-
 #
 # clang flags
 #
@@ -132,10 +80,10 @@ RTS_EMSCRIPTEN_DEBUG=$(RTS_EMSCRIPTEN)
 RTS_EMSCRIPTEN_RELEASE=$(RTS_EMSCRIPTEN) -O2
 
 #
-# Let make automatically search these directorys (tommath and musl) for .c files
+# Let make automatically search this directorys (tommath) for .c files
 #
 
-vpath %.c $(MUSLSRC)/src/math $(MUSLSRC)/src/stdio $(MUSLSRC)/src/string $(MUSLSRC)/src/ctype $(TOMMATHSRC)
+vpath %.c $(TOMMATHSRC)
 
 #
 # Building the libtommath files
@@ -151,23 +99,6 @@ $(TOMMATH_WASM_A): $(TOMMATH_WASM_O)
 	llvm-ar rcs $@ $^
 	llvm-ranlib $@
 
-#
-# Building the musl files
-#
-
-MUSL_WASM_O=$(MUSLFILES:%=_build/wasm/musl_%.o)
-MUSL_WASM_A=_build/libmusl.a
-
-_build/wasm/musl_%.bc: %.c | _build/wasm
-	$(WASM_CLANG) $(CLANG_FLAGS) $(MUSL_FLAGS) -emit-llvm $< --output $@
-
-_build/wasm/musl_%.o: _build/wasm/musl_%.bc
-	$(RTS_EMSCRIPTEN_RELEASE) -o $@ $< 
-
-$(MUSL_WASM_A): $(MUSL_WASM_O)
-	llvm-ar rcs $@ $^
-	llvm-ranlib $@
-
 #
 # The rust code code of the RTS
 #
@@ -323,9 +254,10 @@ test: $(TEST_DEPENDENCIES)
 # Putting it all together
 #
 
-# These symbols from musl are used by the code generator directly
+# These symbols are used by the code generator directly
 EXPORTED_SYMBOLS=\
    __wasm_call_ctors \
+   memcpy \
    memcmp \
    tan \
    asin \
@@ -339,7 +271,7 @@ EXPORTED_SYMBOLS=\
    fmod \
    log \
 
-WASM_A_DEPENDENCIES=$(TOMMATH_WASM_A) $(MUSL_WASM_A)
+WASM_A_DEPENDENCIES=$(TOMMATH_WASM_A)
 LINKER_OPTIONS=\
   -mwasm64 --import-memory --shared --no-entry --gc-sections \
   $(EXPORTED_SYMBOLS:%=--export=%) \

rts/motoko-rts/Cargo.toml

@@ -26,7 +26,6 @@ ic = []
 memory_check = []
 
 [dependencies]
-# libc = { version = "0.2.139", default_features = false }
 motoko-rts-macros = { path = "../motoko-rts-macros" }
 
 [profile.dev]

src/codegen/compile.ml

@@ -1140,6 +1140,7 @@ module RTS = struct
     E.add_func_import env "rts" "set_static_variable" [I64Type; I64Type] [];
     E.add_func_import env "rts" "set_upgrade_instructions" [I64Type] [];
     E.add_func_import env "rts" "get_upgrade_instructions" [] [I64Type];
+    E.add_func_import env "rts" "memcpy" [I64Type; I64Type; I64Type] [I64Type]; (* standard libc memcpy *)
     E.add_func_import env "rts" "memcmp" [I64Type; I64Type; I64Type] [I32Type];
     E.add_func_import env "rts" "version" [] [I64Type];
     E.add_func_import env "rts" "parse_idl_header" [I32Type; I64Type; I64Type; I64Type; I64Type] [];
@@ -1367,7 +1368,7 @@ module Heap = struct
 
   (* Convenience functions related to memory *)
   (* Copying bytes (works on unskewed memory addresses) *)
-  let memcpy env = G.i MemoryCopy
+  let memcpy env = E.call_import env "rts" "memcpy" ^^ G.i Drop
   (* Comparing bytes (works on unskewed memory addresses) *)
   let memcmp env = E.call_import env "rts" "memcmp" ^^ G.i (Convert (Wasm_exts.Values.I64 I64Op.ExtendUI32))
 

test/bench/ok/bignum.drun-run.ok

@@ -2,5 +2,5 @@ ingress Completed: Reply: 0x4449444c016c01b3c4b1f204680100010a000000000000000001
 ingress Completed: Reply: 0x4449444c0000
 debug.print: {cycles = 3_093_961; size = +25_528}
 ingress Completed: Reply: 0x4449444c0000
-debug.print: {cycles = 51_910_521; size = +830_464}
+debug.print: {cycles = 51_915_248; size = +830_464}
 ingress Completed: Reply: 0x4449444c0000

test/bench/ok/candid-subtype-cost.drun-run.ok

@@ -1,4 +1,4 @@
 ingress Completed: Reply: 0x4449444c016c01b3c4b1f204680100010a00000000000000000101
 ingress Completed: Reply: 0x4449444c0000
-debug.print: {cycles = 1_102_518; heap_bytes = +33_872}
+debug.print: {cycles = 1_030_461; heap_bytes = +33_872}
 ingress Completed: Reply: 0x4449444c0000