Return C example and skip it by default

build.gradle

@@ -24,7 +24,7 @@ allprojects {
     version '0.4.1-fl'
 
     // skips building and running for the specified examples
-    ext.skipExamples = ['go-simple', 'rust-regex']
+    ext.skipExamples = ['c-simple', 'go-simple', 'rust-regex']
     // todo disabling Rust regex is temporary because some strings in wasm code exceed the size in 65353 bytes.
 
     repositories {
@@ -71,6 +71,38 @@ project(':examples') {
         dependencies {
             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
+            }
+        }
 
         // Go example helpers
 
@@ -146,10 +178,31 @@ project(':examples') {
     }
 }
 
+project(':examples:c-simple') {
+    if (project.name in skipExamples) {
+        println("[Note!] Building and runnig for ${project.name} was skipped")
+        test.onlyIf { false } // explicit skipping tests
+        compileJava.onlyIf { false } // explicit skipping compile
+        return
+    }
+
+    apply plugin: 'application'
+    ext.wasmCompiledClassName = 'asmble.generated.CSimple'
+    dependencies {
+        compile files('build/wasm-classes')
+    }
+
+    compileJava {
+        dependsOn compileCWasm
+    }
+    mainClassName = 'asmble.examples.csimple.Main'
+}
 
 project(':examples:go-simple') {
     if (project.name in skipExamples) {
         println("[Note!] Building and runnig for ${project.name} was skipped")
+        test.onlyIf { false } // explicit skipping tests
+        compileJava.onlyIf { false } // explicit skipping compile
         return
     }
     apply plugin: 'application'
@@ -164,6 +217,13 @@ project(':examples:go-simple') {
 }
 
  project(':examples:rust-regex') {
+     if (project.name in skipExamples) {
+         println("[Note!] Building and runnig for ${project.name} was skipped")
+         test.onlyIf { false } // explicit skipping tests
+         compileJava.onlyIf { false } // explicit skipping compile
+         compileTestJava.onlyIf { false } // explicit skipping compile
+         return
+     }
      apply plugin: 'application'
      apply plugin: 'me.champeau.gradle.jmh'
      ext.wasmCompiledClassName = 'asmble.generated.RustRegex'
@@ -176,13 +236,6 @@ project(':examples:go-simple') {
      }
      mainClassName = 'asmble.examples.rustregex.Main'
 
-     // the building will run but no test and benchmarks will run
-     if (project.name in skipExamples) {
-         println("[Note!] Building and runnig for ${project.name} was skipped")
-         test.onlyIf { false } // explicit skipping tests
-         return
-     }
-     
      test {
          testLogging.showStandardStreams = true
          testLogging.events 'PASSED', 'SKIPPED'
@@ -197,6 +250,8 @@ project(':examples:go-simple') {
 project(':examples:rust-simple') {
     if (project.name in skipExamples) {
         println("[Note!] Building and runnig for ${project.name} was skipped")
+        test.onlyIf { false } // explicit skipping tests
+        compileJava.onlyIf { false } // explicit skipping compile
         return
     }
     apply plugin: 'application'
@@ -213,6 +268,8 @@ project(':examples:rust-simple') {
 project(':examples:rust-string') {
     if (project.name in skipExamples) {
         println("[Note!] Building and runnig for ${project.name} was skipped")
+        test.onlyIf { false } // explicit skipping tests
+        compileJava.onlyIf { false } // explicit skipping compile
         return
     }
     apply plugin: 'application'

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

@@ -1,6 +1,7 @@
 rootProject.name = 'asmble'
 include 'annotations',
         'compiler',
+        'examples:c-simple',
         'examples:go-simple',
         'examples:rust-regex',
         'examples:rust-simple',