[Tooling] A new framework for executing clang frontend actions.

Summary:
This defines a `clang::tooling::ToolExecutor` interface that can be extended to support different execution plans including standalone execution on a given set of TUs or parallel execution on all TUs in a codebase.

In order to enable multiprocessing execution, tool actions are expected to output result into a `ToolResults` interface provided by executors. The `ToolResults` interface abstracts how results are stored e.g. in-memory for standalone executions or on-disk for large-scale execution.

New executors can be registered as `ToolExecutorPlugin`s via the `ToolExecutorPluginRegistry`. CLI tools can use `createExecutorFromCommandLineArgs` to create a specific registered executor according to the command-line arguments.

This patch also implements `StandaloneToolExecutor` which has the same behavior as the current `ClangTool` interface, i.e. execute frontend actions on a given set of TUs. At this point, it's simply a wrapper around `ClangTool` at this point.

This is still experimental but expected to replace the existing `ClangTool` interface so that specific tools would not need to worry about execution.

Reviewers: klimek, arphaman, hokein, sammccall

Reviewed By: klimek

Subscribers: cfe-commits, djasper, mgorny, omtcyfz

Differential Revision: https://reviews.llvm.org/D34272

llvm-svn: 316653

1 files changed, 89 insertions, 0 deletions

diff --git a/clang/lib/Tooling/Execution.cpp b/clang/lib/Tooling/Execution.cpp
new file mode 100644
index 00000000000..1a078ef7e12
--- /dev/null
+++ b/clang/lib/Tooling/Execution.cpp
@@ -0,0 +1,89 @@
+//===- lib/Tooling/Execution.cpp - Implements tool execution framework. ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Execution.h"
+#include "clang/Tooling/ToolExecutorPluginRegistry.h"
+#include "clang/Tooling/Tooling.h"
+
+LLVM_INSTANTIATE_REGISTRY(clang::tooling::ToolExecutorPluginRegistry)
+
+namespace clang {
+namespace tooling {
+
+static llvm::cl::opt<std::string>
+    ExecutorName("executor", llvm::cl::desc("The name of the executor to use."),
+                 llvm::cl::init("standalone"));
+
+void InMemoryToolResults::addResult(StringRef Key, StringRef Value) {
+  KVResults.push_back({Key.str(), Value.str()});
+}
+
+std::vector<std::pair<std::string, std::string>>
+InMemoryToolResults::AllKVResults() {
+  return KVResults;
+}
+
+void InMemoryToolResults::forEachResult(
+    llvm::function_ref<void(StringRef Key, StringRef Value)> Callback) {
+  for (const auto &KV : KVResults) {
+    Callback(KV.first, KV.second);
+  }
+}
+
+void ExecutionContext::reportResult(StringRef Key, StringRef Value) {
+  Results->addResult(Key, Value);
+}
+
+llvm::Error
+ToolExecutor::execute(std::unique_ptr<FrontendActionFactory> Action) {
+  return execute(std::move(Action), ArgumentsAdjuster());
+}
+
+llvm::Error ToolExecutor::execute(std::unique_ptr<FrontendActionFactory> Action,
+                                  ArgumentsAdjuster Adjuster) {
+  std::vector<
+      std::pair<std::unique_ptr<FrontendActionFactory>, ArgumentsAdjuster>>
+      Actions;
+  Actions.emplace_back(std::move(Action), std::move(Adjuster));
+  return execute(Actions);
+}
+
+llvm::Expected<std::unique_ptr<ToolExecutor>>
+createExecutorFromCommandLineArgs(int &argc, const char **argv,
+                                  llvm::cl::OptionCategory &Category,
+                                  const char *Overview) {
+  auto OptionsParser =
+      CommonOptionsParser::create(argc, argv, Category, llvm::cl::ZeroOrMore,
+                                  /*Overview=*/nullptr);
+  if (!OptionsParser)
+    return OptionsParser.takeError();
+  for (auto I = ToolExecutorPluginRegistry::begin(),
+            E = ToolExecutorPluginRegistry::end();
+       I != E; ++I) {
+    if (I->getName() != ExecutorName) {
+      continue;
+    }
+    std::unique_ptr<ToolExecutorPlugin> Plugin(I->instantiate());
+    llvm::Expected<std::unique_ptr<ToolExecutor>> Executor =
+        Plugin->create(*OptionsParser);
+    if (!Executor) {
+      return llvm::make_error<llvm::StringError>(
+          llvm::Twine("Failed to create '") + I->getName() +
+              "': " + llvm::toString(Executor.takeError()) + "\n",
+          llvm::inconvertibleErrorCode());
+    }
+    return std::move(*Executor);
+  }
+  return llvm::make_error<llvm::StringError>(
+      llvm::Twine("Executor \"") + ExecutorName + "\" is not registered.",
+      llvm::inconvertibleErrorCode());
+}
+
+} // end namespace tooling
+} // end namespace clang