From b04f2a15a04f4af302b54577d9761d3be8e2f85b Mon Sep 17 00:00:00 2001
From: Jon C <me@jonc.dev>
Date: Fri, 6 Sep 2024 13:10:36 +0200
Subject: [PATCH] helloworld: Add C implementation

---
 .github/workflows/main.yml | 32 +++++++++++++++++++++++++
 README.md                  | 37 ++++++++++++++++++++++++++--
 helloworld/c/Makefile      | 49 ++++++++++++++++++++++++++++++++++++++
 helloworld/c/src/main.c    |  9 +++++++
 test-c.sh                  |  9 +++++++
 5 files changed, 134 insertions(+), 2 deletions(-)
 create mode 100644 helloworld/c/Makefile
 create mode 100644 helloworld/c/src/main.c
 create mode 100755 test-c.sh

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a32c2f6..c0689bc 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -70,3 +70,35 @@ jobs:
 
     - name: Build and test program
       run: cd ${{ matrix.program }} && cargo test-sbf
+
+  c-test:
+    name: Run tests against C implementations
+    strategy:
+      matrix:
+        program: [helloworld]
+      fail-fast: false
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/cache@v4
+      with:
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+        key: rust-${{ hashFiles('./Cargo.lock') }}
+
+    - name: Install Rust
+      uses: dtolnay/rust-toolchain@master
+      with:
+        toolchain: 1.78.0
+
+    - name: Install Rust build deps
+      run: ./install-rust-build-deps.sh
+
+    - name: Install Solana
+      run: |
+        ./install-solana.sh
+        echo "$HOME/.local/share/solana/install/active_release/bin" >> $GITHUB_PATH
+
+    - name: Build and test program
+      run: ./test-c.sh ${{ matrix.program }}
diff --git a/README.md b/README.md
index e2d71b8..1fa10ee 100644
--- a/README.md
+++ b/README.md
@@ -60,13 +60,46 @@ cd helloworld/zig
 
 ```console
 cd ..
-SBF_OUT_DIR="./zig/zig-out/lib" cargo test"
+SBF_OUT_DIR="./zig/zig-out/lib" cargo test
 ```
 
 * OR use the helper from the root of this repo to build and test
 
 ```console
-./test-zig helloworld
+./test-zig.sh helloworld
+```
+
+### C
+
+* Install Solana tools
+
+```console
+./install-solana.sh
+```
+
+* Go to a program directory
+
+```console
+cd helloworld/c
+```
+
+* Build a program
+
+```console
+make
+```
+
+* Test it
+
+```console
+cd ..
+SBF_OUT_DIR="./c/out" cargo test
+```
+
+* OR use the helper from the root of this repo to build and test
+
+```console
+./test-c.sh helloworld
 ```
 
 ## Current Programs
diff --git a/helloworld/c/Makefile b/helloworld/c/Makefile
new file mode 100644
index 0000000..5600985
--- /dev/null
+++ b/helloworld/c/Makefile
@@ -0,0 +1,49 @@
+LOCAL_PATH := /home/$(USER)/.local/share/solana/install/active_release/bin/sdk/sbf/c/
+
+.PHONY: all clean
+
+SRC_DIR ?= ./src
+OUT_DIR ?= ./out
+
+all: $(OUT_DIR)/solana_program_rosetta_helloworld.so
+
+clean:
+	rm -rf $(OUT_DIR)
+
+LLVM_DIR = $(LOCAL_PATH)../dependencies/platform-tools/llvm
+LLVM_SYSTEM_INC_DIRS := $(LLVM_DIR)/lib/clang/17/include
+STD_INC_DIRS := $(LLVM_DIR)/include
+STD_LIB_DIRS := $(LLVM_DIR)/lib
+
+CC := $(LLVM_DIR)/bin/clang
+LLD := $(LLVM_DIR)/bin/ld.lld
+
+SYSTEM_INC_DIRS := \
+  $(LOCAL_PATH)inc \
+  $(LLVM_SYSTEM_INC_DIRS) \
+
+C_FLAGS := \
+  -Werror \
+  -O2 \
+  -fno-builtin \
+  -std=c17 \
+  $(addprefix -isystem,$(SYSTEM_INC_DIRS)) \
+  $(addprefix -I,$(STD_INC_DIRS)) \
+  -target sbf \
+  -fPIC
+
+SBF_LLD_FLAGS := \
+  -z notext \
+  -shared \
+  --Bdynamic \
+  $(LOCAL_PATH)sbf.ld \
+  --entry entrypoint \
+  -L $(STD_LIB_DIRS) \
+  -lc \
+
+$(OUT_DIR)/main.o: $(SRC_DIR)/main.c
+	mkdir -p $(OUT_DIR)
+	$(CC) $(C_FLAGS) -o $(OUT_DIR)/main.o -c $(SRC_DIR)/main.c
+
+$(OUT_DIR)/solana_program_rosetta_helloworld.so: $(OUT_DIR)/main.o
+	$(LLD) $(SBF_LLD_FLAGS) -o $(OUT_DIR)/solana_program_rosetta_helloworld.so $(OUT_DIR)/main.o
diff --git a/helloworld/c/src/main.c b/helloworld/c/src/main.c
new file mode 100644
index 0000000..7584de9
--- /dev/null
+++ b/helloworld/c/src/main.c
@@ -0,0 +1,9 @@
+/**
+ * @brief C-based Helloworld BPF program
+ */
+#include <solana_sdk.h>
+
+extern uint64_t entrypoint(const uint8_t *input) {
+  sol_log("Hello world!");
+  return SUCCESS;
+}
diff --git a/test-c.sh b/test-c.sh
new file mode 100755
index 0000000..35b972d
--- /dev/null
+++ b/test-c.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+PROGRAM_NAME="$1"
+ROOT_DIR="$(cd "$(dirname "$0")"; pwd)"
+set -e
+PROGRAM_DIR=$ROOT_DIR/$PROGRAM_NAME
+cd $PROGRAM_DIR/c
+make
+SBF_OUT_DIR="$PROGRAM_DIR/c/out" cargo test --manifest-path "$PROGRAM_DIR/Cargo.toml"