First C example for issue #11

Author: cretz

.gitignore

@@ -1,21 +1,32 @@
+.classpath
+.project
+.settings
 /gradlew
 /gradlew.bat
 /.gradle
 /.idea
 /build
 /gradle
+/compiler/bin
 /compiler/build
 /compiler/out
+/emscripten-runtime/bin
 /emscripten-runtime/build
 /emscripten-runtime/out
+/annotations/bin
 /annotations/build
 /annotations/out
+/examples/c-simple/bin
+/examples/c-simple/build
 /examples/rust-simple/Cargo.lock
+/examples/rust-simple/bin
 /examples/rust-simple/build
 /examples/rust-simple/target
 /examples/rust-string/Cargo.lock
+/examples/rust-string/bin
 /examples/rust-string/build
 /examples/rust-string/target
 /examples/rust-regex/Cargo.lock
+/examples/rust-regex/bin
 /examples/rust-regex/build
 /examples/rust-regex/target

build.gradle

@@ -60,6 +60,40 @@ project(':examples') {
             compileOnly project(':compiler')
         }
 
+        // C/C++ example helpers
+
+        task cToWasm {
+            doFirst {
+                mkdir 'build'
+                exec {
+                    def cFileName = fileTree(dir: 'src', includes: ['*.c']).files.iterator().next()
+                    commandLine 'clang', '--target=wasm32-unknown-unknown-wasm', '-O3', cFileName, '-c', '-o', 'build/lib.wasm'
+                }
+            }   
+        }
+
+        task showCWast(type: JavaExec) {
+            dependsOn cToWasm
+            classpath configurations.compileClasspath
+            main = 'asmble.cli.MainKt'
+            doFirst {
+                args 'translate', 'build/lib.wasm'
+            }
+        }
+
+        task compileCWasm(type: JavaExec) {
+            dependsOn cToWasm
+            classpath configurations.compileClasspath
+            main = 'asmble.cli.MainKt'
+            doFirst {
+                def outFile = 'build/wasm-classes/' + wasmCompiledClassName.replace('.', '/') + '.class'
+                file(outFile).parentFile.mkdirs()
+                args 'compile', 'build/lib.wasm', wasmCompiledClassName, '-out', outFile
+            }
+        }
+
+        // Rust example helpers
+
         ext.rustBuildRelease = true
 
         task rustToWasm(type: Exec) {
@@ -107,6 +141,18 @@ project(':examples') {
     }
 }
 
+project(':examples:c-simple') {
+    apply plugin: 'application'
+    ext.wasmCompiledClassName = 'asmble.generated.CSimple'
+    dependencies {
+        compile files('build/wasm-classes')
+    }
+    compileJava {
+        dependsOn compileCWasm
+    }
+    mainClassName = 'asmble.examples.csimple.Main'
+}
+
 project(':examples:rust-regex') {
     apply plugin: 'application'
     apply plugin: 'me.champeau.gradle.jmh'

examples/README.md

@@ -8,4 +8,10 @@ Compile Rust to WASM and then to the JVM. In order of complexity:
 
 * [rust-simple](rust-simple)
 * [rust-string](rust-string)
-* [rust-regex](rust-regex)
+* [rust-regex](rust-regex)
+
+### C/C++
+
+Compile C to WASM and then to the JVM. In order of complexity:
+
+* [c-simple](c-simple)

examples/c-simple/README.md

@@ -0,0 +1,14 @@
+### Example: C Simple
+
+This shows a simple example of compiling C to WASM and then to the JVM. This is the C version of
+[rust-simple](../rust-simple).
+
+In order to run the C or C++ examples, the latest LLVM binaries must be on the `PATH`, built with the experimental
+WebAssembly target. This can be built by passing `-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=WebAssembly` to `cmake` when
+building WebAssembly. Or it can be downloaded from a nightly build site
+([this one](http://gsdview.appspot.com/wasm-llvm/builds/) was used for these examples at the time of writing).
+
+Everything else is basically the same as [rust-simple](../rust-simple) except with C code and using `clang`. To run
+execute the following from the root `asmble` dir:
+
+    gradlew --no-daemon :examples:c-simple:run

examples/c-simple/src/lib.c

@@ -0,0 +1,3 @@
+int addOne(int x) {
+  return x + 1;
+}

examples/c-simple/src/main/java/asmble/examples/csimple/Main.java

@@ -0,0 +1,13 @@
+package asmble.examples.csimple;
+
+import java.lang.invoke.MethodHandle;
+
+import asmble.generated.CSimple;
+
+class Main {
+    public static void main(String[] args) {
+        // Doesn't need memory or method table
+        CSimple simple = new CSimple(0, new MethodHandle[0]);
+        System.out.println("25 + 1 = " + simple.addOne(25));
+    }
+}

settings.gradle

@@ -2,6 +2,7 @@ rootProject.name = 'asmble'
 include 'annotations',
         'compiler',
         'emscripten-runtime',
+        'examples:c-simple',
         'examples:rust-regex',
         'examples:rust-simple',
         'examples:rust-string'