[modules] Fix incorrect diagnostic mapping computation when a module changes

diagnostic settings using _Pragma within a macro.

The AST writer had previously been assuming that all diagnostic state
transitions would occur within a FileID corresponding to a file. When a
diagnostic state change occured within a macro, it was unable to form a
location for that state change and would instead corrupt the diagnostic state
of the "root" node (and thus that of the main compilation).

Also introduce a "#pragma clang __debug diag_mapping" debugging utility
that I added to track this issue down.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@324695 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/Diagnostic.h

@@ -262,6 +262,10 @@ private:
       CurDiagStateLoc = SourceLocation();
     }
 
+    /// Produce a debugging dump of the diagnostic state.
+    LLVM_DUMP_METHOD void dump(SourceManager &SrcMgr,
+                               StringRef DiagName = StringRef()) const;
+
     /// Grab the most-recently-added state point.
     DiagState *getCurDiagState() const { return CurDiagState; }
     /// Get the location at which a diagnostic state was last added.
@@ -409,6 +413,11 @@ public:
   DiagnosticsEngine &operator=(const DiagnosticsEngine &) = delete;
   ~DiagnosticsEngine();
 
+  LLVM_DUMP_METHOD void dump() const { DiagStatesByLoc.dump(*SourceMgr); }
+  LLVM_DUMP_METHOD void dump(StringRef DiagName) const {
+    DiagStatesByLoc.dump(*SourceMgr, DiagName);
+  }
+
   const IntrusiveRefCntPtr<DiagnosticIDs> &getDiagnosticIDs() const {
     return Diags;
   }

include/clang/Basic/SourceManager.h

@@ -1137,6 +1137,18 @@ public:
   /// be used by clients.
   SourceLocation getImmediateSpellingLoc(SourceLocation Loc) const;
 
+  /// \brief Form a SourceLocation from a FileID and Offset pair.
+  SourceLocation getComposedLoc(FileID FID, unsigned Offset) const {
+    bool Invalid = false;
+    const SrcMgr::SLocEntry &Entry = getSLocEntry(FID, &Invalid);
+    if (Invalid)
+      return SourceLocation();
+
+    unsigned GlobalOffset = Entry.getOffset() + Offset;
+    return Entry.isFile() ? SourceLocation::getFileLoc(GlobalOffset)
+                          : SourceLocation::getMacroLoc(GlobalOffset);
+  }
+
   /// \brief Decompose the specified location into a raw FileID + Offset pair.
   ///
   /// The first element is the FileID, the second is the offset from the

lib/Basic/Diagnostic.cpp

@@ -236,6 +236,96 @@ DiagnosticsEngine::DiagStateMap::getFile(SourceManager &SrcMgr,
   return &F;
 }
 
+void DiagnosticsEngine::DiagStateMap::dump(SourceManager &SrcMgr,
+                                           StringRef DiagName) const {
+  llvm::errs() << "diagnostic state at ";
+  CurDiagStateLoc.dump(SrcMgr);
+  llvm::errs() << ": " << CurDiagState << "\n";
+
+  for (auto &F : Files) {
+    FileID ID = F.first;
+    File &File = F.second;
+
+    bool PrintedOuterHeading = false;
+    auto PrintOuterHeading = [&] {
+      if (PrintedOuterHeading) return;
+      PrintedOuterHeading = true;
+
+      llvm::errs() << "File " << &File << " <FileID " << ID.getHashValue()
+                   << ">: " << SrcMgr.getBuffer(ID)->getBufferIdentifier();
+      if (F.second.Parent) {
+        std::pair<FileID, unsigned> Decomp =
+            SrcMgr.getDecomposedIncludedLoc(ID);
+        assert(File.ParentOffset == Decomp.second);
+        llvm::errs() << " parent " << File.Parent << " <FileID "
+                     << Decomp.first.getHashValue() << "> ";
+        SrcMgr.getLocForStartOfFile(Decomp.first)
+              .getLocWithOffset(Decomp.second)
+              .dump(SrcMgr);
+      }
+      if (File.HasLocalTransitions)
+        llvm::errs() << " has_local_transitions";
+      llvm::errs() << "\n";
+    };
+
+    if (DiagName.empty())
+      PrintOuterHeading();
+
+    for (DiagStatePoint &Transition : File.StateTransitions) {
+      bool PrintedInnerHeading = false;
+      auto PrintInnerHeading = [&] {
+        if (PrintedInnerHeading) return;
+        PrintedInnerHeading = true;
+
+        PrintOuterHeading();
+        llvm::errs() << "  ";
+        SrcMgr.getLocForStartOfFile(ID)
+              .getLocWithOffset(Transition.Offset)
+              .dump(SrcMgr);
+        llvm::errs() << ": state " << Transition.State << ":\n";
+      };
+
+      if (DiagName.empty())
+        PrintInnerHeading();
+
+      for (auto &Mapping : *Transition.State) {
+        StringRef Option =
+            DiagnosticIDs::getWarningOptionForDiag(Mapping.first);
+        if (!DiagName.empty() && DiagName != Option)
+          continue;
+
+        PrintInnerHeading();
+        llvm::errs() << "    ";
+        if (Option.empty())
+          llvm::errs() << "<unknown " << Mapping.first << ">";
+        else
+          llvm::errs() << Option;
+        llvm::errs() << ": ";
+
+        switch (Mapping.second.getSeverity()) {
+        case diag::Severity::Ignored: llvm::errs() << "ignored"; break;
+        case diag::Severity::Remark: llvm::errs() << "remark"; break;
+        case diag::Severity::Warning: llvm::errs() << "warning"; break;
+        case diag::Severity::Error: llvm::errs() << "error"; break;
+        case diag::Severity::Fatal: llvm::errs() << "fatal"; break;
+        }
+
+        if (!Mapping.second.isUser())
+          llvm::errs() << " default";
+        if (Mapping.second.isPragma())
+          llvm::errs() << " pragma";
+        if (Mapping.second.hasNoWarningAsError())
+          llvm::errs() << " no-error";
+        if (Mapping.second.hasNoErrorAsFatal())
+          llvm::errs() << " no-fatal";
+        if (Mapping.second.wasUpgradedFromWarning())
+          llvm::errs() << " overruled";
+        llvm::errs() << "\n";
+      }
+    }
+  }
+}
+
 void DiagnosticsEngine::PushDiagStatePoint(DiagState *State,
                                            SourceLocation Loc) {
   assert(Loc.isValid() && "Adding invalid loc point");

lib/Lex/Pragma.cpp

@@ -1053,6 +1053,20 @@ struct PragmaDebugHandler : public PragmaHandler {
         PP.Diag(Identifier, diag::warn_pragma_debug_missing_argument)
             << II->getName();
       }
+    } else if (II->isStr("diag_mapping")) {
+      Token DiagName;
+      PP.LexUnexpandedToken(DiagName);
+      if (DiagName.is(tok::eod))
+        PP.getDiagnostics().dump();
+      else if (DiagName.is(tok::string_literal) && !DiagName.hasUDSuffix()) {
+        StringLiteralParser Literal(DiagName, PP);
+        if (Literal.hadError)
+          return;
+        PP.getDiagnostics().dump(Literal.GetString());
+      } else {
+        PP.Diag(DiagName, diag::warn_pragma_debug_missing_argument)
+            << II->getName();
+      }
     } else if (II->isStr("llvm_fatal_error")) {
       llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");
     } else if (II->isStr("llvm_unreachable")) {

lib/Serialization/ASTReader.cpp

@@ -5761,6 +5761,8 @@ void ASTReader::ReadPragmaDiagnosticMappings(DiagnosticsEngine &Diag) {
       Initial.ExtBehavior = (diag::Severity)Flags;
       FirstState = ReadDiagState(Initial, SourceLocation(), true);
 
+      assert(F.OriginalSourceFileID.isValid());
+
       // Set up the root buffer of the module to start with the initial
       // diagnostic state of the module itself, to cover files that contain no
       // explicit transitions (for which we did not serialize anything).
@@ -5781,6 +5783,7 @@ void ASTReader::ReadPragmaDiagnosticMappings(DiagnosticsEngine &Diag) {
              "Invalid data, missing pragma diagnostic states");
       SourceLocation Loc = ReadSourceLocation(F, Record[Idx++]);
       auto IDAndOffset = SourceMgr.getDecomposedLoc(Loc);
+      assert(IDAndOffset.first.isValid() && "invalid FileID for transition");
       assert(IDAndOffset.second == 0 && "not a start location for a FileID");
       unsigned Transitions = Record[Idx++];
 

lib/Serialization/ASTWriter.cpp

@@ -3092,8 +3092,11 @@ void ASTWriter::WritePragmaDiagnosticMappings(const DiagnosticsEngine &Diag,
         !FileIDAndFile.second.HasLocalTransitions)
       continue;
     ++NumLocations;
-    AddSourceLocation(Diag.SourceMgr->getLocForStartOfFile(FileIDAndFile.first),
-                      Record);
+
+    SourceLocation Loc = Diag.SourceMgr->getComposedLoc(FileIDAndFile.first, 0);
+    assert(!Loc.isInvalid() && "start loc for valid FileID is invalid");
+    AddSourceLocation(Loc, Record);
+
     Record.push_back(FileIDAndFile.second.StateTransitions.size());
     for (auto &StatePoint : FileIDAndFile.second.StateTransitions) {
       Record.push_back(StatePoint.Offset);

test/Modules/Inputs/diag_flags.h

@@ -1 +1,4 @@
+#define pragma _Pragma("clang diagnostic push") _Pragma("clang diagnostic error \"-Wpadded\"") _Pragma("clang diagnostic pop")
+pragma
+
 struct Padded { char x; int y; };

test/Modules/diag-flags.cpp

@@ -3,24 +3,24 @@
 // For an implicit module, all that matters are the warning flags in the user.
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -emit-module -fmodules-cache-path=%t -fmodule-name=diag_flags -x c++ %S/Inputs/module.map -fmodules-ts
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -Wpadded
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DERROR -Wpadded -Werror
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DERROR -Werror=padded
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -DLOCAL_WARNING -Wpadded
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DERROR -DLOCAL_ERROR -Wpadded -Werror
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DERROR -DLOCAL_ERROR -Werror=padded
 //
 // For an explicit module, all that matters are the warning flags in the module build.
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -emit-module -fmodule-name=diag_flags -x c++ %S/Inputs/module.map -fmodules-ts -o %t/nodiag.pcm
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -fmodule-file=%t/nodiag.pcm -Wpadded
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -fmodule-file=%t/nodiag.pcm -Werror -Wpadded
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -fmodule-file=%t/nodiag.pcm -Wpadded -DLOCAL_WARNING
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -fmodule-file=%t/nodiag.pcm -Werror -Wpadded -DLOCAL_ERROR
 //
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -emit-module -fmodule-name=diag_flags -x c++ %S/Inputs/module.map -fmodules-ts -o %t/warning.pcm -Wpadded
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/warning.pcm
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/warning.pcm -Werror=padded
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/warning.pcm -Werror=padded -DLOCAL_ERROR
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/warning.pcm -Werror
 //
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -emit-module -fmodule-name=diag_flags -x c++ %S/Inputs/module.map -fmodules-ts -o %t/werror-no-error.pcm -Werror -Wpadded -Wno-error=padded
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/werror-no-error.pcm
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/werror-no-error.pcm -Wno-padded
-// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/werror-no-error.pcm -Werror=padded
+// RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DWARNING -fmodule-file=%t/werror-no-error.pcm -Werror=padded -DLOCAL_ERROR
 //
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -emit-module -fmodule-name=diag_flags -x c++ %S/Inputs/module.map -fmodules-ts -o %t/error.pcm -Werror=padded
 // RUN: %clang_cc1 -triple %itanium_abi_triple -fmodules -fimplicit-module-maps -verify -fmodules-cache-path=%t -I %S/Inputs %s -fmodules-ts -DERROR -fmodule-file=%t/error.pcm -Wno-padded
@@ -35,10 +35,22 @@ import diag_flags;
 // Diagnostic flags from the module user make no difference to diagnostics
 // emitted within the module when using an explicitly-loaded module.
 #if ERROR
-// expected-error@diag_flags.h:14 {{padding struct}}
+// expected-error@diag_flags.h:4 {{padding struct}}
 #elif WARNING
-// expected-warning@diag_flags.h:14 {{padding struct}}
-#else
-// expected-no-diagnostics
+// expected-warning@diag_flags.h:4 {{padding struct}}
 #endif
 int arr[sizeof(Padded)];
+
+// Diagnostic flags from the module make no difference to diagnostics emitted
+// in the module user.
+#if LOCAL_ERROR
+// expected-error@+4 {{padding struct}}
+#elif LOCAL_WARNING
+// expected-warning@+2 {{padding struct}}
+#endif
+struct Padded2 { char x; int y; };
+int arr2[sizeof(Padded2)];
+
+#if !ERROR && !WARNING && !LOCAL_ERROR && !LOCAL_WARNING
+// expected-no-diagnostics
+#endif