[clangd] Config: CompileFlags.Remove

Summary: While here, add documentation to CompileFlags and CompileFlags.Add.

Reviewers: hokein

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83705

diff --git a/clang-tools-extra/clangd/CompileCommands.h b/clang-tools-extra/clangd/CompileCommands.h
index c9f2d66..84c4c2a 100644 (file)
--- a/clang-tools-extra/clangd/CompileCommands.h
+++ b/clang-tools-extra/clangd/CompileCommands.h
@@ -59,6 +59,12 @@ private:
 // The table-building strategy may not make sense outside clangd.
 class ArgStripper {
 public:
+  ArgStripper() = default;
+  ArgStripper(ArgStripper &&) = default;
+  ArgStripper(const ArgStripper &) = delete;
+  ArgStripper &operator=(ArgStripper &&) = default;
+  ArgStripper &operator=(const ArgStripper &) = delete;
+
   // Adds the arg to the set which should be removed.
   //
   // Recognized clang flags are stripped semantically. When "-I" is stripped:

diff --git a/clang-tools-extra/clangd/ConfigCompile.cpp b/clang-tools-extra/clangd/ConfigCompile.cpp
index 04c0df8..568e029 100644 (file)
--- a/clang-tools-extra/clangd/ConfigCompile.cpp
+++ b/clang-tools-extra/clangd/ConfigCompile.cpp
@@ -23,6 +23,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "CompileCommands.h"
 #include "Config.h"
 #include "ConfigFragment.h"
 #include "support/Logger.h"
@@ -122,6 +123,19 @@ struct FragmentCompiler {
   }
 
   void compile(Fragment::CompileFlagsBlock &&F) {
+    if (!F.Remove.empty()) {
+      auto Remove = std::make_shared<ArgStripper>();
+      for (auto &A : F.Remove)
+        Remove->strip(*A);
+      Out.Apply.push_back([Remove(std::shared_ptr<const ArgStripper>(
+                              std::move(Remove)))](Config &C) {
+        C.CompileFlags.Edits.push_back(
+            [Remove](std::vector<std::string> &Args) {
+              Remove->process(Args);
+            });
+      });
+    }
+
     if (!F.Add.empty()) {
       std::vector<std::string> Add;
       for (auto &A : F.Add)

diff --git a/clang-tools-extra/clangd/ConfigFragment.h b/clang-tools-extra/clangd/ConfigFragment.h
index 42f9ec2..5cc8749 100644 (file)
--- a/clang-tools-extra/clangd/ConfigFragment.h
+++ b/clang-tools-extra/clangd/ConfigFragment.h
@@ -117,9 +117,39 @@ struct Fragment {
   };
   IfBlock If;
 
+  /// Conditions in the CompileFlags block affect how a file is parsed.
+  ///
+  /// clangd emulates how clang would interpret a file.
+  /// By default, it behaves roughly like `clang $FILENAME`, but real projects
+  /// usually require setting the include path (with the `-I` flag), defining
+  /// preprocessor symbols, configuring warnings etc.
+  /// Often, a compilation database specifies these compile commands. clangd
+  /// searches for compile_commands.json in parents of the source file.
+  ///
+  /// This section modifies how the compile command is constructed.
   struct CompileFlagsBlock {
+    /// List of flags to append to the compile command.
     std::vector<Located<std::string>> Add;
-  } CompileFlags;
+    /// List of flags to remove from the compile command.
+    ///
+    /// - If the value is a recognized clang flag (like "-I") then it will be
+    ///   removed along with any arguments. Synonyms like --include-dir= will
+    ///   also be removed.
+    /// - Otherwise, if the value ends in * (like "-DFOO=*") then any argument
+    ///   with the prefix will be removed.
+    /// - Otherwise any argument exactly matching the value is removed.
+    ///
+    /// In all cases, -Xclang is also removed where needed.
+    ///
+    /// Example:
+    ///   Command: clang++ --include-directory=/usr/include -DFOO=42 foo.cc
+    ///   Remove: [-I, -DFOO=*]
+    ///   Result: clang++ foo.cc
+    ///
+    /// Flags added by the same CompileFlags entry will not be removed.
+    std::vector<Located<std::string>> Remove;
+  };
+  CompileFlagsBlock CompileFlags;
 };
 
 } // namespace config

diff --git a/clang-tools-extra/clangd/ConfigYAML.cpp b/clang-tools-extra/clangd/ConfigYAML.cpp
index ef6003b..7e86e37 100644 (file)
--- a/clang-tools-extra/clangd/ConfigYAML.cpp
+++ b/clang-tools-extra/clangd/ConfigYAML.cpp
@@ -63,6 +63,10 @@ private:
       if (auto Values = scalarValues(N))
         F.Add = std::move(*Values);
     });
+    Dict.handle("Remove", [&](Node &N) {
+      if (auto Values = scalarValues(N))
+        F.Remove = std::move(*Values);
+    });
     Dict.parse(N);
   }
 

diff --git a/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp b/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
index 825d687..0337347 100644 (file)
--- a/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
+++ b/clang-tools-extra/clangd/unittests/ConfigCompileTests.cpp
@@ -91,10 +91,12 @@ TEST_F(ConfigCompileTests, Condition) {
 
 TEST_F(ConfigCompileTests, CompileCommands) {
   Frag.CompileFlags.Add.emplace_back("-foo");
-  std::vector<std::string> Argv = {"clang", "a.cc"};
+  Frag.CompileFlags.Remove.emplace_back("--include-directory=");
+  std::vector<std::string> Argv = {"clang", "-I", "bar/", "a.cc"};
   EXPECT_TRUE(compileAndApply());
-  EXPECT_THAT(Conf.CompileFlags.Edits, SizeIs(1));
-  Conf.CompileFlags.Edits.front()(Argv);
+  EXPECT_THAT(Conf.CompileFlags.Edits, SizeIs(2));
+  for (auto &Edit : Conf.CompileFlags.Edits)
+    Edit(Argv);
   EXPECT_THAT(Argv, ElementsAre("clang", "a.cc", "-foo"));
 }