[clang-tools-extra] 4160f4c - Reland [clangd] Parse std::make_unique, and emit template diagnostics at expansion.

Sam McCall via cfe-commits cfe-commits at lists.llvm.org
Fri Jun 12 07:18:37 PDT 2020


Author: Sam McCall
Date: 2020-06-12T16:18:26+02:00
New Revision: 4160f4c37615f6d5b7615666eb202d9cbb58f4bb

URL: https://github.com/llvm/llvm-project/commit/4160f4c37615f6d5b7615666eb202d9cbb58f4bb
DIFF: https://github.com/llvm/llvm-project/commit/4160f4c37615f6d5b7615666eb202d9cbb58f4bb.diff

LOG: Reland [clangd] Parse std::make_unique, and emit template diagnostics at expansion.

This was originally 658af9435071 and reverted in 665dbe91f2ed.
The clang bug this triggered was fixed in 05ed3efc2ac.

Added: 
    

Modified: 
    clang-tools-extra/clangd/Diagnostics.cpp
    clang-tools-extra/clangd/Diagnostics.h
    clang-tools-extra/clangd/Preamble.cpp
    clang-tools-extra/clangd/unittests/DiagnosticsTests.cpp
    clang/include/clang/Frontend/PrecompiledPreamble.h
    clang/lib/Frontend/PrecompiledPreamble.cpp

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clangd/Diagnostics.cpp b/clang-tools-extra/clangd/Diagnostics.cpp
index f1fbaf4646ba..da554ff8c331 100644
--- a/clang-tools-extra/clangd/Diagnostics.cpp
+++ b/clang-tools-extra/clangd/Diagnostics.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
@@ -120,49 +121,96 @@ Range diagnosticRange(const clang::Diagnostic &D, const LangOptions &L) {
   return halfOpenToRange(M, R);
 }
 
-// Returns whether the \p D is modified.
-bool adjustDiagFromHeader(Diag &D, const clang::Diagnostic &Info,
-                          const LangOptions &LangOpts) {
-  // We only report diagnostics with at least error severity from headers.
-  // Use default severity to avoid noise with -Werror.
-  if (!Info.getDiags()->getDiagnosticIDs()->isDefaultMappingAsError(
-          Info.getID()))
-    return false;
-
-  const SourceManager &SM = Info.getSourceManager();
-  const SourceLocation &DiagLoc = SM.getExpansionLoc(Info.getLocation());
-  SourceLocation IncludeInMainFile;
+// Try to find a location in the main-file to report the diagnostic D.
+// Returns a description like "in included file", or nullptr on failure.
+const char *getMainFileRange(const Diag &D, const SourceManager &SM,
+                             SourceLocation DiagLoc, Range &R) {
+  // Look for a note in the main file indicating template instantiation.
+  for (const auto &N : D.Notes) {
+    if (N.InsideMainFile) {
+      switch (N.ID) {
+      case diag::note_template_class_instantiation_was_here:
+      case diag::note_template_class_explicit_specialization_was_here:
+      case diag::note_template_class_instantiation_here:
+      case diag::note_template_member_class_here:
+      case diag::note_template_member_function_here:
+      case diag::note_function_template_spec_here:
+      case diag::note_template_static_data_member_def_here:
+      case diag::note_template_variable_def_here:
+      case diag::note_template_enum_def_here:
+      case diag::note_template_nsdmi_here:
+      case diag::note_template_type_alias_instantiation_here:
+      case diag::note_template_exception_spec_instantiation_here:
+      case diag::note_template_requirement_instantiation_here:
+      case diag::note_evaluating_exception_spec_here:
+      case diag::note_default_arg_instantiation_here:
+      case diag::note_default_function_arg_instantiation_here:
+      case diag::note_explicit_template_arg_substitution_here:
+      case diag::note_function_template_deduction_instantiation_here:
+      case diag::note_deduced_template_arg_substitution_here:
+      case diag::note_prior_template_arg_substitution:
+      case diag::note_template_default_arg_checking:
+      case diag::note_concept_specialization_here:
+      case diag::note_nested_requirement_here:
+      case diag::note_checking_constraints_for_template_id_here:
+      case diag::note_checking_constraints_for_var_spec_id_here:
+      case diag::note_checking_constraints_for_class_spec_id_here:
+      case diag::note_checking_constraints_for_function_here:
+      case diag::note_constraint_substitution_here:
+      case diag::note_constraint_normalization_here:
+      case diag::note_parameter_mapping_substitution_here:
+        R = N.Range;
+        return "in template";
+      default:
+        break;
+      }
+    }
+  }
+  // Look for where the file with the error was #included.
   auto GetIncludeLoc = [&SM](SourceLocation SLoc) {
     return SM.getIncludeLoc(SM.getFileID(SLoc));
   };
-  for (auto IncludeLocation = GetIncludeLoc(DiagLoc); IncludeLocation.isValid();
+  for (auto IncludeLocation = GetIncludeLoc(SM.getExpansionLoc(DiagLoc));
+       IncludeLocation.isValid();
        IncludeLocation = GetIncludeLoc(IncludeLocation)) {
     if (clangd::isInsideMainFile(IncludeLocation, SM)) {
-      IncludeInMainFile = IncludeLocation;
-      break;
+      R.start = sourceLocToPosition(SM, IncludeLocation);
+      R.end = sourceLocToPosition(
+          SM,
+          Lexer::getLocForEndOfToken(IncludeLocation, 0, SM, LangOptions()));
+      return "in included file";
     }
   }
-  if (IncludeInMainFile.isInvalid())
-    return false;
+  return nullptr;
+}
 
-  // Update diag to point at include inside main file.
-  D.File = SM.getFileEntryForID(SM.getMainFileID())->getName().str();
-  D.Range.start = sourceLocToPosition(SM, IncludeInMainFile);
-  D.Range.end = sourceLocToPosition(
-      SM, Lexer::getLocForEndOfToken(IncludeInMainFile, 0, SM, LangOpts));
-  D.InsideMainFile = true;
+// Place the diagnostic the main file, rather than the header, if possible:
+//   - for errors in included files, use the #include location
+//   - for errors in template instantiation, use the instantation location
+// In both cases, add the original header location as a note.
+bool tryMoveToMainFile(Diag &D, FullSourceLoc DiagLoc) {
+  const SourceManager &SM = DiagLoc.getManager();
+  DiagLoc = DiagLoc.getExpansionLoc();
+  Range R;
+  const char *Prefix = getMainFileRange(D, SM, DiagLoc, R);
+  if (!Prefix)
+    return false;
 
   // Add a note that will point to real diagnostic.
   const auto *FE = SM.getFileEntryForID(SM.getFileID(DiagLoc));
-  D.Notes.emplace_back();
-  Note &N = D.Notes.back();
+  D.Notes.emplace(D.Notes.begin());
+  Note &N = D.Notes.front();
   N.AbsFile = std::string(FE->tryGetRealPathName());
   N.File = std::string(FE->getName());
   N.Message = "error occurred here";
-  N.Range = diagnosticRange(Info, LangOpts);
+  N.Range = D.Range;
 
+  // Update diag to point at include inside main file.
+  D.File = SM.getFileEntryForID(SM.getMainFileID())->getName().str();
+  D.Range = std::move(R);
+  D.InsideMainFile = true;
   // Update message to mention original file.
-  D.Message = llvm::Twine("in included file: ", D.Message).str();
+  D.Message = llvm::formatv("{0}: {1}", Prefix, D.Message);
   return true;
 }
 
@@ -475,6 +523,7 @@ void StoreDiags::BeginSourceFile(const LangOptions &Opts,
 }
 
 void StoreDiags::EndSourceFile() {
+  flushLastDiag();
   LangOpts = None;
 }
 
@@ -512,12 +561,14 @@ static void fillNonLocationData(DiagnosticsEngine::Level DiagLevel,
 void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
                                   const clang::Diagnostic &Info) {
   DiagnosticConsumer::HandleDiagnostic(DiagLevel, Info);
+  bool OriginallyError =
+      Info.getDiags()->getDiagnosticIDs()->isDefaultMappingAsError(
+          Info.getID());
 
   if (Info.getLocation().isInvalid()) {
     // Handle diagnostics coming from command-line arguments. The source manager
     // is *not* available at this point, so we cannot use it.
-    if (!Info.getDiags()->getDiagnosticIDs()->isDefaultMappingAsError(
-            Info.getID())) {
+    if (!OriginallyError) {
       IgnoreDiagnostics::log(DiagLevel, Info);
       return; // non-errors add too much noise, do not show them.
     }
@@ -525,6 +576,8 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     flushLastDiag();
 
     LastDiag = Diag();
+    LastDiagLoc.reset();
+    LastDiagOriginallyError = OriginallyError;
     LastDiag->ID = Info.getID();
     fillNonLocationData(DiagLevel, Info, *LastDiag);
     LastDiag->InsideMainFile = true;
@@ -550,6 +603,7 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     D.File = std::string(SM.getFilename(Info.getLocation()));
     D.AbsFile = getCanonicalPath(
         SM.getFileEntryForID(SM.getFileID(Info.getLocation())), SM);
+    D.ID = Info.getID();
     return D;
   };
 
@@ -634,10 +688,9 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     LastPrimaryDiagnosticWasSuppressed = false;
 
     LastDiag = Diag();
-    LastDiag->ID = Info.getID();
     FillDiagBase(*LastDiag);
-    if (!InsideMainFile)
-      LastDiagWasAdjusted = adjustDiagFromHeader(*LastDiag, Info, *LangOpts);
+    LastDiagLoc.emplace(Info.getLocation(), Info.getSourceManager());
+    LastDiagOriginallyError = OriginallyError;
 
     if (!Info.getFixItHints().empty())
       AddFix(true /* try to invent a message instead of repeating the diag */);
@@ -679,16 +732,28 @@ void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
 void StoreDiags::flushLastDiag() {
   if (!LastDiag)
     return;
-  if (!isBlacklisted(*LastDiag) && mentionsMainFile(*LastDiag) &&
-      (!LastDiagWasAdjusted ||
-       // Only report the first diagnostic coming from each particular header.
-       IncludeLinesWithErrors.insert(LastDiag->Range.start.line).second)) {
-    Output.push_back(std::move(*LastDiag));
-  } else {
-    vlog("Dropped diagnostic: {0}: {1}", LastDiag->File, LastDiag->Message);
+  auto Finish = llvm::make_scope_exit([&, NDiags(Output.size())] {
+    if (Output.size() == NDiags) // No new diag emitted.
+      vlog("Dropped diagnostic: {0}: {1}", LastDiag->File, LastDiag->Message);
+    LastDiag.reset();
+  });
+
+  if (isBlacklisted(*LastDiag))
+    return;
+  // Move errors that occur from headers into main file.
+  if (!LastDiag->InsideMainFile && LastDiagLoc && LastDiagOriginallyError) {
+    if (tryMoveToMainFile(*LastDiag, *LastDiagLoc)) {
+      // Suppress multiple errors from the same inclusion.
+      if (!IncludedErrorLocations
+               .insert({LastDiag->Range.start.line,
+                        LastDiag->Range.start.character})
+               .second)
+        return;
+    }
   }
-  LastDiag.reset();
-  LastDiagWasAdjusted = false;
+  if (!mentionsMainFile(*LastDiag))
+    return;
+  Output.push_back(std::move(*LastDiag));
 }
 
 } // namespace clangd

diff  --git a/clang-tools-extra/clangd/Diagnostics.h b/clang-tools-extra/clangd/Diagnostics.h
index ebf86ba8716a..58f69287f256 100644
--- a/clang-tools-extra/clangd/Diagnostics.h
+++ b/clang-tools-extra/clangd/Diagnostics.h
@@ -13,6 +13,7 @@
 #include "support/Path.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
+#include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/None.h"
@@ -64,6 +65,7 @@ struct DiagBase {
   // Since File is only descriptive, we store a separate flag to distinguish
   // diags from the main file.
   bool InsideMainFile = false;
+  unsigned ID; // e.g. member of clang::diag, or clang-tidy assigned ID.
 };
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const DiagBase &D);
 
@@ -82,7 +84,6 @@ struct Note : DiagBase {};
 
 /// A top-level diagnostic that may have Notes and Fixes.
 struct Diag : DiagBase {
-  unsigned ID;      // e.g. member of clang::diag, or clang-tidy assigned ID.
   std::string Name; // if ID was recognized.
   // The source of this diagnostic.
   enum {
@@ -145,9 +146,10 @@ class StoreDiags : public DiagnosticConsumer {
   std::vector<Diag> Output;
   llvm::Optional<LangOptions> LangOpts;
   llvm::Optional<Diag> LastDiag;
-  /// Set iff adjustDiagFromHeader resulted in changes to LastDiag.
-  bool LastDiagWasAdjusted = false;
-  llvm::DenseSet<int> IncludeLinesWithErrors;
+  llvm::Optional<FullSourceLoc> LastDiagLoc; // Valid only when LastDiag is set.
+  bool LastDiagOriginallyError = false;      // Valid only when LastDiag is set.
+
+  llvm::DenseSet<std::pair<unsigned, unsigned>> IncludedErrorLocations;
   bool LastPrimaryDiagnosticWasSuppressed = false;
 };
 

diff  --git a/clang-tools-extra/clangd/Preamble.cpp b/clang-tools-extra/clangd/Preamble.cpp
index af7229ecb888..837ae7e5a5bb 100644
--- a/clang-tools-extra/clangd/Preamble.cpp
+++ b/clang-tools-extra/clangd/Preamble.cpp
@@ -13,6 +13,7 @@
 #include "support/FSProvider.h"
 #include "support/Logger.h"
 #include "support/Trace.h"
+#include "clang/AST/DeclTemplate.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SourceLocation.h"
@@ -98,6 +99,19 @@ class CppFilePreambleCallbacks : public PreambleCallbacks {
     return IWYUHandler.get();
   }
 
+  bool shouldSkipFunctionBody(Decl *D) override {
+    // Generally we skip function bodies in preambles for speed.
+    // We can make exceptions for functions that are cheap to parse and
+    // instantiate, widely used, and valuable (e.g. commonly produce errors).
+    if (const auto *FT = llvm::dyn_cast<clang::FunctionTemplateDecl>(D)) {
+      if (const auto *II = FT->getDeclName().getAsIdentifierInfo())
+        // std::make_unique is trivial, and we diagnose bad constructor calls.
+        if (II->isStr("make_unique") && FT->isInStdNamespace())
+          return false;
+    }
+    return true;
+  }
+
 private:
   PathRef File;
   PreambleParsedCallback ParsedCallback;

diff  --git a/clang-tools-extra/clangd/unittests/DiagnosticsTests.cpp b/clang-tools-extra/clangd/unittests/DiagnosticsTests.cpp
index e675d01ad59f..dbeff4deb444 100644
--- a/clang-tools-extra/clangd/unittests/DiagnosticsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/DiagnosticsTests.cpp
@@ -45,9 +45,9 @@ ::testing::Matcher<const Diag &> WithFix(::testing::Matcher<Fix> FixMatcher1,
   return Field(&Diag::Fixes, UnorderedElementsAre(FixMatcher1, FixMatcher2));
 }
 
-::testing::Matcher<const Diag &>
-WithNote(::testing::Matcher<Note> NoteMatcher) {
-  return Field(&Diag::Notes, ElementsAre(NoteMatcher));
+template <typename... NoteMatcherTypes>
+::testing::Matcher<const Diag &> WithNote(NoteMatcherTypes... NoteMatcher) {
+  return Field(&Diag::Notes, ElementsAre(NoteMatcher...));
 }
 
 MATCHER_P2(Diag, Range, Message,
@@ -272,6 +272,51 @@ TEST(DiagnosticsTest, ClangTidy) {
                   "use a trailing return type for this function")))));
 }
 
+TEST(DiagnosticTest, TemplatesInHeaders) {
+  // Diagnostics from templates defined in headers are placed at the expansion.
+  Annotations Main(R"cpp(
+    Derived<int> [[y]]; // error-ok
+  )cpp");
+  Annotations Header(R"cpp(
+    template <typename T>
+    struct Derived : [[T]] {};
+  )cpp");
+  TestTU TU = TestTU::withCode(Main.code());
+  TU.HeaderCode = Header.code().str();
+  EXPECT_THAT(
+      TU.build().getDiagnostics(),
+      ElementsAre(AllOf(
+          Diag(Main.range(), "in template: base specifier must name a class"),
+          WithNote(Diag(Header.range(), "error occurred here"),
+                   Diag(Main.range(), "in instantiation of template class "
+                                      "'Derived<int>' requested here")))));
+}
+
+TEST(DiagnosticTest, MakeUnique) {
+  // We usually miss diagnostics from header functions as we don't parse them.
+  // std::make_unique is an exception.
+  Annotations Main(R"cpp(
+    struct S { S(char*); };
+    auto x = std::[[make_unique]]<S>(42); // error-ok
+  )cpp");
+  TestTU TU = TestTU::withCode(Main.code());
+  TU.HeaderCode = R"cpp(
+    namespace std {
+    // These mocks aren't quite right - we omit unique_ptr for simplicity.
+    // forward is included to show its body is not needed to get the diagnostic.
+    template <typename T> T&& forward(T& t) { return static_cast<T&&>(t); }
+    template <typename T, typename... A> T* make_unique(A&&... args) {
+       return new T(std::forward<A>(args)...);
+    }
+    }
+  )cpp";
+  EXPECT_THAT(TU.build().getDiagnostics(),
+              UnorderedElementsAre(
+                  Diag(Main.range(),
+                       "in template: "
+                       "no matching constructor for initialization of 'S'")));
+}
+
 TEST(DiagnosticTest, NoMultipleDiagnosticInFlight) {
   Annotations Main(R"cpp(
     template <typename T> struct Foo {

diff  --git a/clang/include/clang/Frontend/PrecompiledPreamble.h b/clang/include/clang/Frontend/PrecompiledPreamble.h
index 94c9d0135013..0f7e9d895a00 100644
--- a/clang/include/clang/Frontend/PrecompiledPreamble.h
+++ b/clang/include/clang/Frontend/PrecompiledPreamble.h
@@ -34,6 +34,7 @@ class FileSystem;
 namespace clang {
 class CompilerInstance;
 class CompilerInvocation;
+class Decl;
 class DeclGroupRef;
 class PCHContainerOperations;
 
@@ -293,6 +294,10 @@ class PreambleCallbacks {
   virtual std::unique_ptr<PPCallbacks> createPPCallbacks();
   /// The returned CommentHandler will be added to the preprocessor if not null.
   virtual CommentHandler *getCommentHandler();
+  /// Determines which function bodies are parsed, by default skips everything.
+  /// Only used if FrontendOpts::SkipFunctionBodies is true.
+  /// See ASTConsumer::shouldSkipFunctionBody.
+  virtual bool shouldSkipFunctionBody(Decl *D) { return true; }
 };
 
 enum class BuildPreambleError {

diff  --git a/clang/lib/Frontend/PrecompiledPreamble.cpp b/clang/lib/Frontend/PrecompiledPreamble.cpp
index 31c5f18eeeec..6cdfc595dcae 100644
--- a/clang/lib/Frontend/PrecompiledPreamble.cpp
+++ b/clang/lib/Frontend/PrecompiledPreamble.cpp
@@ -255,6 +255,10 @@ class PrecompilePreambleConsumer : public PCHGenerator {
     Action.setEmittedPreamblePCH(getWriter());
   }
 
+  bool shouldSkipFunctionBody(Decl *D) override {
+    return Action.Callbacks.shouldSkipFunctionBody(D);
+  }
+
 private:
   PrecompilePreambleAction &Action;
   std::unique_ptr<raw_ostream> Out;


        


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