refactor(post processing): Use r8 CLI to both generate stack map frames and optimise - reduces build time by 1-2s.

Also no longer includes the ENTIRE kotlin stdlib in every produced jar file, reducing size by 98%-99%, and removes optimise2 and stackmapadder as both tasks are now handled by the r8 cli. Adds needed vendoring steps to Makefile. Needed refactor of java-linker to support this.

Author: IntegralPilot

.gitignore

@@ -18,4 +18,7 @@
 
 # Generated by GenerateFiles.py
 /config.toml
-jvm-unknown-unknown.json
+jvm-unknown-unknown.json
+
+# Vendored files
+**/vendor/*

Makefile

@@ -1,7 +1,7 @@
 # === Phony Targets ===
 .PHONY: all help clean rust-components rust clean-rust java-linker clean-java-linker \
-        shim-metadata-gen clean-shim-metadata-gen stackmapadder clean-stackmapadder \
-        library clean-library gen-files clean-gen-files ci optimise2 clean-optimise2
+        shim-metadata-gen clean-shim-metadata-gen vendor-r8 clean-vendor-r8 \
+        library clean-library gen-files clean-gen-files ci
 
 # === Terminal Colors ===
 GREEN  := \033[1;32m
@@ -11,18 +11,16 @@ RESET  := \033[0m
 # === Directory Variables ===
 JAVA_LINKER_DIR := java-linker
 SHIM_METADATA_GEN_DIR := shim-metadata-gen
-STACKMAPADDER_DIR := stackmapadder
-OPTIMISE2_DIR := optimise2
 LIBRARY_DIR := library
 LIBRARY_JAR := $(LIBRARY_DIR)/build/libs/library-0.1.0.jar
 RUST_SOURCES := $(shell find $(SHIM_METADATA_GEN_DIR)/src -type f -name '*.rs')
 
 # === Default Target ===
 ifeq ($(IS_CI),1)
-all: rust java-linker stackmapadder optimise2
+all: rust java-linker vendor-r8
 	@echo "$(GREEN)✨ Build complete in CI mode! ✨$(RESET)"
 else
-all: rust gen-files java-linker stackmapadder optimise2
+all: rust gen-files java-linker vendor-r8
 	@echo "$(GREEN)✨ Build complete! ✨$(RESET)"
 endif
 
@@ -41,7 +39,6 @@ help:
 	@echo "  make rust-components      - Install needed Rust components"
 	@echo "  make rust                 - Build the Rust root project"
 	@echo "  make java-linker          - Build the Java Linker subproject"
-	@echo "  make stackmapadder        - Build the ASM processor"
 	@echo "  make library              - Build the standard library shim"
 	@echo "  make gen-files            - Generate necessary files from templates"
 	@echo "  make clean-*              - Clean individual components"
@@ -96,39 +93,6 @@ clean-shim-metadata-gen-json-files:
 	    rm -f $(SHIM_METADATA_GEN_DIR)/*.json; \
 	fi
 
-# === ASM Processors (Gradle) ===
-stackmapadder:
-	@echo "$(CYAN)⚙️  Building Stack map adder...$(RESET)"
-ifeq ($(IS_CI),1)
-	cd $(STACKMAPADDER_DIR) && gradle --no-daemon shadowJar
-else
-	cd $(STACKMAPADDER_DIR) && gradle shadowJar
-endif
-
-clean-stackmapadder:
-	@echo "$(CYAN)🧹 Cleaning ASM processor...$(RESET)"
-ifeq ($(IS_CI),1)
-	cd $(STACKMAPADDER_DIR) && gradle --no-daemon clean
-else
-	cd $(STACKMAPADDER_DIR) && gradle clean
-endif
-
-optimise2:
-	@echo "$(CYAN)⚙️  Building optimise2...$(RESET)"
-ifeq ($(IS_CI),1)
-	cd $(OPTIMISE2_DIR) && gradle --no-daemon shadowJar
-else
-	cd $(OPTIMISE2_DIR) && gradle shadowJar
-endif
-
-clean-optimise2:
-	@echo "$(CYAN)🧹 Cleaning optimise2...$(RESET)
-ifeq ($(IS_CI),1)
-	cd $(OPTIMISE2_DIR) && gradle --no-daemon clean
-else
-	cd $(OPTIMISE2_DIR) && gradle clean
-endif
-
 # === Standard Library Shim (Gradle) ===
 library: $(LIBRARY_JAR)
 
@@ -158,6 +122,16 @@ clean-gen-files:
 	@echo "$(CYAN)🧹 Cleaning template generated files...$(RESET)"
 	rm -f jvm-unknown-unknown.json config.toml
 
+# === Vendoring of R8 ===
+vendor-r8:
+	@echo "$(CYAN)📦 Vendoring R8...$(RESET)"
+	mkdir -p ./vendor && curl -L -o ./vendor/r8.jar https://maven.google.com/com/android/tools/r8/8.9.35/r8-8.9.35.jar
+	@echo "$(CYAN)📦 R8 vendored!$(RESET)"
+
+clean-vendor-r8:
+	@echo "$(CYAN)🧹 Cleaning vendored R8...$(RESET)"
+	rm -rf ./vendor/r8.jar
+
 # === Clean All ===
-clean: clean-rust clean-java-linker clean-stackmapadder clean-library clean-shim-metadata-gen clean-gen-files
+clean: clean-rust clean-java-linker clean-library clean-shim-metadata-gen clean-gen-files clean-vendor-r8
 	@echo "$(GREEN)🧼 All clean!$(RESET)"

Readme.md

@@ -73,10 +73,8 @@ All examples live in `tests/binary` and are compiled to JVM bytecode & run/teste
 4. **OOMIR → JVM Classfile**  
    Translate to `.class` files using `ristretto_classfile`.  
    _(see `src/lower2.rs`)_  
-5. **Post‑Process Stack Map Frames**  
-   Kotlin `stackmapadder` (built with ASM library) adds verification frames and applys some further optimisations to the class files.
-6. **JAR Optimisation**
-   `optimise2` (based on `r8`) optimises the final jar file.
+5. **R8 pass**  
+   `r8` adds stack map frames (neeeded to run on JVM 8+) and applies some further optimisations.
 6. **Link & Package**  
    `java-linker` bundles `.class` files into a runnable `.jar` with `META-INF/MANIFEST.MF`.
 
@@ -85,8 +83,7 @@ All examples live in `tests/binary` and are compiled to JVM bytecode & run/teste
 ## 🛠 Prerequisites
 
 - **Rust Nightly** (`rustup default nightly`)  
-- **JDK 8+** (`java` in PATH)  
-- **Gradle** (`gradle` in PATH)  
+- **JDK 8+** (`java` in PATH, and the `JAVA_HOME` environment variable set)
 - **Python 3** (`python3` in PATH)
 
 ---
@@ -106,8 +103,6 @@ This will compile:
 
 - `rustc_codegen_jvm` backend library  
 - `java-linker`  
-- `stackmapadder` 
-- `optimise2`
 - Kotlin shim for `core` (once core support is reached, this will no longer be needed)  
 - Generate `config.toml` & `jvm-unknown-unknown.json`  
 
@@ -167,11 +162,10 @@ Look for `✅ All tests passed!` or inspect `.generated` files on failure.
 │   ├── lower2.rs          # OOMIR → JVM bytecode
 │   └── oomir.rs           # OOMIR definitions
 ├── java-linker/           # Bundles .class files into .jar
-├── stackmapadder/         # Kotlin StackMapFrame generator
-├── optimise2/             # Jar optimiser
 ├── tests/binary/          # Integration tests
 ├── library/               # Kotlin shim for Rust core library
 ├── shim-metadata-gen/     # Generates core.json metadata
+├── proguard/              # .pro rules used for r8
 ├── Makefile               # build & gen-files
 ├── config.toml.template
 ├── jvm-unknown-unknown.json.template

Tester.py

@@ -64,7 +64,7 @@ def process_test(test_dir: str, release_mode: bool):
                   os.path.join(test_dir, "target", "jvm-unknown-unknown", target_dir, f"{test_name}.jar"))
 
     jar_path = os.path.join(test_dir, "target", "jvm-unknown-unknown", target_dir, f"{test_name}.jar")
-    proc = run_command(["java", "-jar", jar_path]) 
+    proc = run_command(["java", "-cp", f"library/build/distributions/library-0.1.0/lib/library-0.1.0.jar:library/build/distributions/library-0.1.0/lib/kotlin-stdlib-2.1.20.jar:{jar_path}", test_name]) 
 
     expected_returncode_file = os.path.join(test_dir, "java-returncode.expected")
     if os.path.exists(expected_returncode_file):

config.toml.template

@@ -2,7 +2,7 @@
 rustflags = [
   "-Z", "codegen-backend=../../../target/debug/librustc_codegen_jvm.dylib",
   "-C", "linker=../../../java-linker/target/debug/java-linker",
-  "-C", "link-args=../../../library/build/distributions/library-0.1.0/lib/library-0.1.0.jar ../../../library/build/distributions/library-0.1.0/lib/kotlin-stdlib-2.1.20.jar --stackmapadder ../../../stackmapadder/build/libs/stackmapadder-1.0-SNAPSHOT-all.jar --known-good kotlin-stdlib --optimizer ../../../optimise2/build/libs/optimise2-1.0-SNAPSHOT-all.jar --proguard-config ../../../proguard/default.pro"
+  "-C", "link-args=../../../library/build/distributions/library-0.1.0/lib/library-0.1.0.jar ../../../library/build/distributions/library-0.1.0/lib/kotlin-stdlib-2.1.20.jar ../../../library/build/distributions/library-0.1.0/lib/annotations-13.0.jar --r8-jar ../../../vendor/r8.jar --proguard-config ../../../proguard/default.pro"
 ]
 
 # Throwing a JVM exception will unwind and give a stack trace, no need for rust to handle unwinding.