From 63a8b62d790b7c84165d391cba83e135fc464181 Mon Sep 17 00:00:00 2001
From: Jake Hillion <jakehillion@meta.com>
Date: Fri, 16 Aug 2024 18:40:03 +0100
Subject: [PATCH] build and test LLVM version 16

Add LLVM-16 to the Nix builds and CI matrix. Also add the option to explicitly
select an LLVM version so the CircleCI build can still work as before.

We should support at least LLVM-17 currently, but there appears to be a
significant performance regression in compiling the generated code for large
variants that I'm going to debug separately. The long term goal is to support
and test all versions 15 and up.

Test plan:
- CI
---
 .circleci/config.yml              | 2 +-
 .github/workflows/ci.yml          | 2 +-
 .github/workflows/test-report.yml | 2 +-
 CMakeLists.txt                    | 9 +++++++--
 flake.nix                         | 3 ++-
 5 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index dba98d7..fc4572a 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -101,7 +101,7 @@ jobs:
       - run:
           name: Build
           command: |
-            /tmp/cmake/build/bin/cmake -G Ninja -B build/ -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
+            /tmp/cmake/build/bin/cmake -G Ninja -B build/ -DLLVM_REQUESTED_VERSION=15 -DWITH_FLAKY_TESTS=Off -DCODE_COVERAGE=On -DWARNINGS_AS_ERRORS=<< parameters.warnings_as_errors >>
             ninja -C build/
             # Testing rubbish:
             cp test/ci.oid.toml build/testing.oid.toml
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 071a433..254b1a9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: 16-core-ubuntu
     strategy:
       matrix:
-        llvm_version: [15]
+        llvm_version: [15, 16]
     steps:
     - uses: actions/checkout@v4.1.7
     - uses: cachix/install-nix-action@v27
diff --git a/.github/workflows/test-report.yml b/.github/workflows/test-report.yml
index 91524b1..300808b 100644
--- a/.github/workflows/test-report.yml
+++ b/.github/workflows/test-report.yml
@@ -14,7 +14,7 @@ jobs:
     steps:
     - uses: dorny/test-reporter@v1
       with:
-        artifact: test-results-15
+        artifact: test-results-16
         name: CTest Tests
         path: results.xml
         reporter: jest-junit
diff --git a/CMakeLists.txt b/CMakeLists.txt
index de8f86f..65161e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -218,11 +218,16 @@ find_package(Boost REQUIRED COMPONENTS
 )
 message(STATUS "Linking Boost libraries: ${Boost_LIBRARIES}")
 
-### LLVM and Clang - Preferring Clang 15
-find_package(LLVM 15 REQUIRED CONFIG)
+### LLVM and Clang
+find_package(LLVM ${LLVM_REQUESTED_VERSION} REQUIRED CONFIG)
+
 message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
 message(STATUS "Using LLVMConfig.cmake in: ${LLVM_DIR}")
 
+if((${LLVM_VERSION_MAJOR} VERSION_LESS 15) OR (${LLVM_VERSION_MAJOR} VERSION_GREATER 16))
+  message(SEND_ERROR "Object Introspection currently requires an LLVM version between 15 and 16!")
+endif()
+
 find_package(Clang REQUIRED CONFIG)
 message(STATUS "Found Clang ${LLVM_PACKAGE_VERSION}")
 message(STATUS "Using ClangConfig.cmake in: ${Clang_DIR}")
diff --git a/flake.nix b/flake.nix
index f925621..39fdec3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -99,9 +99,10 @@
       in
       {
         packages = rec {
-          default = oid-llvm15;
+          default = oid-llvm16;
 
           oid-llvm15 = mkOidPackage pkgs.llvmPackages_15;
+          oid-llvm16 = mkOidPackage pkgs.llvmPackages_16;
         };
 
         apps.default = {