Set LLVM minimum version to 18

Also update all locations where LLVM versions are specified to use 18 at minimum and it updates the readme with information about our LLVM version strategy.

PiperOrigin-RevId: 748242057
Change-Id: Ia494d88a8cedb1c42256fed063ec3bf2c8863c21

Author: okunz

.github/workflows/ubuntu-cmake-contrib.yml

@@ -24,10 +24,10 @@ jobs:
         include:
           - compiler: clang
             compiler-version: 11
-            libclang-version: 11
+            libclang-version: 18
           - compiler: gcc
             compiler-version: 10
-            libclang-version: 11
+            libclang-version: 18
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.ignore-errors }}
 

.github/workflows/ubuntu-cmake.yml

@@ -11,48 +11,42 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          # Ubuntu 22.04: Use preinstalled Clang 12.0.1, 13.0.1 and 14.0.0
+          # Ubuntu 22.04: Use preinstalled Clang 20.0.0, 19.0.0 and 18.0.0
           - os: ubuntu-22.04
             compiler: clang
             compiler-version: 14
-            libclang-version: 14
+            libclang-version: 18
             ignore-errors: false
           - os: ubuntu-22.04
             compiler: clang
             compiler-version: 13
-            libclang-version: 13
+            libclang-version: 18
             ignore-errors: false
           - os: ubuntu-22.04
             compiler: clang
             compiler-version: 12
-            libclang-version: 12
+            libclang-version: 18
             ignore-errors: false
           # Ubuntu 22.04: Use preinstalled GCC 9.5.0, 10.4.0, 11.3.0, 12.1.0
           - os: ubuntu-22.04
             compiler: gcc
             compiler-version: 12
-            libclang-version: 14
+            libclang-version: 18
             ignore-errors: false
           - os: ubuntu-22.04
             compiler: gcc
             compiler-version: 11
-            libclang-version: 14
+            libclang-version: 18
             ignore-errors: false
           - os: ubuntu-22.04
             compiler: gcc
             compiler-version: 10
-            libclang-version: 14
+            libclang-version: 18
             ignore-errors: false
           - os: ubuntu-22.04
             compiler: gcc
             compiler-version: 9
-            libclang-version: 14
-            ignore-errors: false
-          # Ubuntu 20.04
-          - os: ubuntu-20.04
-            compiler: gcc
-            compiler-version: 8
-            libclang-version: 12
+            libclang-version: 18
             ignore-errors: false
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.ignore-errors }}

sandboxed_api/bazel/llvm_config.bzl

@@ -72,7 +72,7 @@ def _locate_llvm_config_tool(repository_ctx):
         The path to the llvm-config tool.
     """
     max_version = 20
-    min_version = 10
+    min_version = 18
 
     llvm_config_tool = repository_ctx.execute(
         ["which"] +  # Prints all arguments it finds in the system PATH

sandboxed_api/tools/clang_generator/CMakeLists.txt

@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Minimum supported: LLVM 11.0.0
+# Minimum supported: LLVM 18.0.0
 find_package(LLVM REQUIRED)
 find_package(Clang REQUIRED)
-if(LLVM_VERSION VERSION_LESS "11.0.0")
-  message(FATAL_ERROR "SAPI header generator needs LLVM 11 or newer")
+if(LLVM_VERSION VERSION_LESS "18.0.0")
+  message(FATAL_ERROR "SAPI header generator needs LLVM 18 or newer")
 endif()
 
 add_library(sapi_generator
@@ -55,11 +55,9 @@ list(APPEND _sapi_generator_llvm_comp
   BinaryFormat
   Demangle
 )
-if(LLVM_VERSION VERSION_GREATER_EQUAL "15.0.0")
-  list(APPEND _sapi_generator_llvm_comp
-    WindowsDriver # Always needed
-  )
-endif()
+list(APPEND _sapi_generator_llvm_comp
+  WindowsDriver # Always needed
+)
 llvm_map_components_to_libnames(_sapi_generator_llvm_libs
   ${_sapi_generator_llvm_comp}
 )

sandboxed_api/tools/clang_generator/frontend_action_test_util.cc

@@ -70,13 +70,8 @@ absl::Status RunClangTool(
     }
   }
 
-#if LLVM_VERSION_MAJOR >= 10
   clang::tooling::ToolInvocation invocation(command_line, std::move(action),
                                             files.get());
-#else
-  clang::tooling::ToolInvocation invocation(command_line, action.get(),
-                                            files.get());
-#endif
   if (!invocation.run()) {
     return absl::UnknownError("Tool invocation failed");
   }

sandboxed_api/tools/clang_generator/frontend_action_test_util.h

@@ -79,13 +79,6 @@ class FrontendActionTest : public ::testing::Test {
                                   std::move(action));
   }
 
-  // Runs the specified frontend action. Provided for compatibility with LLVM <
-  // 10. Takes ownership.
-  absl::Status RunFrontendAction(absl::string_view code,
-                                 clang::FrontendAction* action) {
-    return RunFrontendAction(code, absl::WrapUnique(action));
-  }
-
  private:
   std::string input_file_ = "input.cc";
   absl::flat_hash_map<std::string, std::string> file_contents_;

sandboxed_api/tools/clang_generator/generator.h

@@ -138,15 +138,9 @@ class GeneratorFactory : public clang::tooling::FrontendActionFactory {
       : emitter_(emitter), options_(options) {}
 
  private:
-#if LLVM_VERSION_MAJOR >= 10
   std::unique_ptr<clang::FrontendAction> create() override {
     return std::make_unique<GeneratorAction>(emitter_, options_);
   }
-#else
-  clang::FrontendAction* create() override {
-    return new GeneratorAction(emitter_, options_);
-  }
-#endif
 
   bool runInvocation(
       std::shared_ptr<clang::CompilerInvocation> invocation,

sandboxed_api/tools/clang_generator/types.cc

@@ -25,21 +25,11 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/QualTypeNames.h"
 #include "clang/AST/Type.h"
-#include "llvm/Config/llvm-config.h"
 #include "llvm/Support/Casting.h"
 
 namespace sapi {
 namespace {
 
-bool IsFunctionReferenceType(clang::QualType qual) {
-#if LLVM_VERSION_MAJOR >= 9
-  return qual->isFunctionReferenceType();
-#else
-  const auto* ref = qual->getAs<clang::ReferenceType>();
-  return ref && ref->getPointeeType()->isFunctionType();
-#endif
-}
-
 bool IsProtoBuf(const clang::RecordDecl* decl) {
   const auto* cxxdecl = llvm::dyn_cast<const clang::CXXRecordDecl>(decl);
   if (cxxdecl == nullptr) {
@@ -96,7 +86,7 @@ void TypeCollector::CollectRelatedTypes(clang::QualType qual) {
     return;
   }
 
-  if (qual->isFunctionPointerType() || IsFunctionReferenceType(qual) ||
+  if (qual->isFunctionPointerType() || qual->isFunctionReferenceType() ||
       qual->isMemberFunctionPointerType()) {
     if (const auto* function_type = qual->getPointeeOrArrayElementType()
                                         ->getAs<clang::FunctionProtoType>()) {
@@ -143,7 +133,7 @@ std::string GetQualTypeName(const clang::ASTContext& context,
   clang::QualType unqual = qual.getLocalUnqualifiedType();
 
   // This is to get to the actual name of function pointers.
-  if (unqual->isFunctionPointerType() || IsFunctionReferenceType(unqual) ||
+  if (unqual->isFunctionPointerType() || unqual->isFunctionReferenceType() ||
       unqual->isMemberFunctionPointerType()) {
     unqual = unqual->getPointeeType();
   }
@@ -219,13 +209,7 @@ namespace {
 // type. Keeps top-level typedef types intact.
 clang::QualType MaybeRemoveConst(const clang::ASTContext& context,
                                  clang::QualType qual) {
-  if (
-#if LLVM_VERSION_MAJOR < 13
-      qual->getAs<clang::TypedefType>() == nullptr
-#else
-      !qual->isTypedefNameType()
-#endif
-      && IsPointerOrReference(qual)) {
+  if (!qual->isTypedefNameType() && IsPointerOrReference(qual)) {
     clang::QualType pointee_qual = qual->getPointeeType();
     pointee_qual.removeLocalConst();
     qual = context.getPointerType(pointee_qual);