Merge branch 'topic/free_usage_in_java' into 'master'

Correct the 'free' usage in the Java bindings to avoid errors on Windows

Closes AdaCore#648

See merge request eng/libadalang/langkit!832

Author: HugoGGuerrier

langkit/templates/java_api/jni_impl_c.mako

@@ -2161,7 +2161,7 @@ ${api.jni_func_sig("unit_filename", "jstring")}(
     jstring res = to_j_string(env, res_native);
 
     // Free the native allocated string
-    free((void *) res_native);
+    ${nat("free")}((void *) res_native);
 
     // Return the result
     return res;

langkit/templates/java_api/main_class.mako

@@ -2632,11 +2632,11 @@ public class ${ctx.lib_name.camel} {
             PointerWrapper reference;
 
             if(ImageInfo.inImageCode()) {
-                CCharPointer charsetNative =
+                final CCharPointer charsetNative =
                     charset == null ?
                     WordFactory.nullPointer() :
                     toCString(charset);
-                AnalysisContextNative resNative =
+                final AnalysisContextNative resNative =
                     NI_LIB.${nat("allocate_analysis_context")}();
 
                 NI_LIB.${nat("initialize_analysis_context")}(
@@ -3060,7 +3060,7 @@ public class ${ctx.lib_name.camel} {
                     this.reference.ni()
                 );
                 absoluteFile = toJString(resNative);
-                UnmanagedMemory.free(resNative);
+                NI_LIB.${nat("free")}(resNative);
             } else {
                 absoluteFile = JNI_LIB.${nat("unit_filename")}(this);
             }

langkit/templates/java_api/ni_lib.mako

@@ -309,6 +309,15 @@
 
         ${exts.include_extension(ctx.ext("java_api", "ni_funcs"))}
 
+        // ----- Util functions -----
+
+        /** Util function to free langkit side allocated memory */
+        @CompilerDirectives.TruffleBoundary
+        @CFunction
+        public static native void ${nat("free")}(
+            PointerBase pointer
+        );
+
         // ----- Exception functions -----
 
         /** Get the last exception raised by langkit */