[clang][Tooling] Infer target and mode from argv[0] when using JSONCompilationDatabase

Summary:
Wraps JSON compilation database with a target and mode adding database
wrapper. So that driver can correctly figure out which toolchain to use.

Note that clients that wants to make use of this target discovery mechanism
needs to link in TargetsInfos and initialize them at startup.

Reviewers: ilya-biryukov

Subscribers: mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63755

llvm-svn: 364386

3 files changed, 63 insertions, 1 deletions

diff --git a/clang/lib/Tooling/CMakeLists.txt b/clang/lib/Tooling/CMakeLists.txt
index 6ed2f25acda..5a380fb8cce 100644
--- a/clang/lib/Tooling/CMakeLists.txt
+++ b/clang/lib/Tooling/CMakeLists.txt
@@ -17,6 +17,7 @@ add_clang_library(clangTooling
   Execution.cpp
   FileMatchTrie.cpp
   FixIt.cpp
+  GuessTargetAndModeCompilationDatabase.cpp
   InterpolatingCompilationDatabase.cpp
   JSONCompilationDatabase.cpp
   Refactoring.cpp
diff --git a/clang/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp b/clang/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp
new file mode 100644
index 00000000000..ac3faf1b01f
--- /dev/null
+++ b/clang/lib/Tooling/GuessTargetAndModeCompilationDatabase.cpp
@@ -0,0 +1,57 @@
+//===- GuessTargetAndModeCompilationDatabase.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/CompilationDatabase.h"
+#include "clang/Tooling/Tooling.h"
+#include <memory>
+
+namespace clang {
+namespace tooling {
+
+namespace {
+class TargetAndModeAdderDatabase : public CompilationDatabase {
+public:
+  TargetAndModeAdderDatabase(std::unique_ptr<CompilationDatabase> Base)
+      : Base(std::move(Base)) {
+    assert(this->Base != nullptr);
+  }
+
+  std::vector<std::string> getAllFiles() const override {
+    return Base->getAllFiles();
+  }
+
+  std::vector<CompileCommand> getAllCompileCommands() const override {
+    return addTargetAndMode(Base->getAllCompileCommands());
+  }
+
+  std::vector<CompileCommand>
+  getCompileCommands(StringRef FilePath) const override {
+    return addTargetAndMode(Base->getCompileCommands(FilePath));
+  }
+
+private:
+  std::vector<CompileCommand>
+  addTargetAndMode(std::vector<CompileCommand> Cmds) const {
+    for (auto &Cmd : Cmds) {
+      if (Cmd.CommandLine.empty())
+        continue;
+      addTargetAndModeForProgramName(Cmd.CommandLine, Cmd.CommandLine.front());
+    }
+    return Cmds;
+  }
+  std::unique_ptr<CompilationDatabase> Base;
+};
+} // namespace
+
+std::unique_ptr<CompilationDatabase>
+inferTargetAndDriverMode(std::unique_ptr<CompilationDatabase> Base) {
+  return llvm::make_unique<TargetAndModeAdderDatabase>(std::move(Base));
+}
+
+} // namespace tooling
+} // namespace clang
diff --git a/clang/lib/Tooling/JSONCompilationDatabase.cpp b/clang/lib/Tooling/JSONCompilationDatabase.cpp
index 0ee9d174b44..76a82b0fd9b 100644
--- a/clang/lib/Tooling/JSONCompilationDatabase.cpp
+++ b/clang/lib/Tooling/JSONCompilationDatabase.cpp
@@ -14,7 +14,9 @@
 #include "clang/Basic/LLVM.h"
 #include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/CompilationDatabasePluginRegistry.h"
+#include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
@@ -165,7 +167,9 @@ class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {
     llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");
     auto Base = JSONCompilationDatabase::loadFromFile(
         JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
-    return Base ? inferMissingCompileCommands(std::move(Base)) : nullptr;
+    return Base ? inferTargetAndDriverMode(
+                      inferMissingCompileCommands(std::move(Base)))
+                : nullptr;
   }
 };