update sdk:

- move to wasi-sdk 10
 - use new log function

Dockerfile

@@ -1,13 +1,12 @@
-FROM ubuntu:19.04
+FROM ubuntu:18.04
 
 RUN apt-get update \
  && apt-get install -y ca-certificates \
                        curl \
                        git \
-                       make \
-                       libtinfo5
+                       make
 
-RUN curl -L https://github.com/CraneStation/wasi-sdk/releases/download/wasi-sdk-6/wasi-sdk-6.0-linux.tar.gz | tar xz --strip-components=1 -C /
+RUN curl -L https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-10/wasi-sdk-10.0-linux.tar.gz | tar xz --strip-components=1 -C /
 
 VOLUME /code
 WORKDIR /code

Makefile

@@ -1,11 +1,11 @@
 TARGET = hello_world
-CC = /opt/wasi-sdk/bin/clang
-SYSROOT = /opt/wasi-sdk/share/wasi-sysroot
+CC = /bin/clang
+SYSROOT = /share/wasi-sysroot
 TARGET_TRIPLE = wasm32-unknown-wasi
 CFLAGS = -nostartfiles -fvisibility=hidden
 LDFLAGS = -Wl,--no-entry,--demangle,--allow-undefined
 EXPORT_FUNCS = --export=allocate,--export=deallocate,--export=invoke
-SDK = sdk/allocator.c sdk/logger.c sdk/syscalls_stubs.c
+SDK = sdk/allocator.c sdk/syscalls_stubs.c
 SRC = src/main.c
 
 .PHONY: default all clean

sdk/logger.c

@@ -1,15 +0,0 @@
-#include "logger.h"
-
-#define __LOGGER_IMPORT(name) \
-    __attribute__((__import_module__("logger"), __import_name__(#name)))
-
-void __write(char ch) __LOGGER_IMPORT(write);
-void __flush() __LOGGER_IMPORT(flush);
-
-void wasm_log(const char *str, int len) {
-    for(int byteId = 0; byteId < len; ++byteId) {
-        __write(str[byteId]);
-    }
-
-    __flush();
-}

sdk/logger.h

@@ -1,12 +1,15 @@
 #ifndef FLUENCE_C_SDK_LOGGER_H
 #define FLUENCE_C_SDK_LOGGER_H
 
+#define __LOGGER_IMPORT(name) \
+    __attribute__((__import_module__("logger"), __import_name__(#name)))
+
 /**
- * Writes provided string to Wasm VM logger.
+ * Writes provided utf8 string to Wasm VM logger.
  *
- * @param str a pointer to a message that should be logged.
- * @param len a size of a message that should be logged.
+ * @param str a pointer to the string that should be logged.
+ * @param len a size of the string that should be logged.
  */
-void wasm_log(const char *str, int len);
+void log_utf8_string(const char *str, int len) __LOGGER_IMPORT(log_utf8_string);
 
 #endif //FLUENCE_C_SDK_LOGGER_H