[flang] Intermix messages from parser and semantic analysis

flang/examples/FeatureList/FeatureList.cpp

@@ -775,7 +775,9 @@ class FeatureListAction : public PluginParseTreeAction {
     }
   }
 
-  bool beginSourceFileAction() override { return runPrescan() && runParse(); }
+  bool beginSourceFileAction() override {
+    return runPrescan() && runParse(/*emitMessages=*/true);
+  }
 };
 
 static FrontendPluginRegistry::Add<FeatureListAction> X(

flang/include/flang/Frontend/FrontendAction.h

@@ -112,7 +112,7 @@ class FrontendAction {
   bool runPrescan();
   // Parse the current input file. Return False if fatal errors are reported,
   // True otherwise.
-  bool runParse();
+  bool runParse(bool emitMessages);
   // Run semantic checks for the current input file. Return False if fatal
   // errors are reported, True otherwise.
   bool runSemanticChecks();

flang/include/flang/Semantics/semantics.h

@@ -312,7 +312,7 @@ class Semantics {
     return context_.FindScope(where);
   }
   bool AnyFatalError() const { return context_.AnyFatalError(); }
-  void EmitMessages(llvm::raw_ostream &) const;
+  void EmitMessages(llvm::raw_ostream &);
   void DumpSymbols(llvm::raw_ostream &);
   void DumpSymbolsSources(llvm::raw_ostream &) const;
 

flang/lib/Frontend/FrontendAction.cpp

@@ -153,7 +153,7 @@ bool FrontendAction::runPrescan() {
   return !reportFatalScanningErrors();
 }
 
-bool FrontendAction::runParse() {
+bool FrontendAction::runParse(bool emitMessages) {
   CompilerInstance &ci = this->getInstance();
 
   // Parse. In case of failure, report and return.
@@ -163,9 +163,11 @@ bool FrontendAction::runParse() {
     return false;
   }
 
-  // Report the diagnostics from getParsing
-  ci.getParsing().messages().Emit(llvm::errs(), ci.getAllCookedSources());
-
+  if (emitMessages) {
+    // Report any non-fatal diagnostics from getParsing now rather than
+    // combining them with messages from semantics.
+    ci.getParsing().messages().Emit(llvm::errs(), ci.getAllCookedSources());
+  }
   return true;
 }
 
@@ -174,10 +176,14 @@ bool FrontendAction::runSemanticChecks() {
   std::optional<parser::Program> &parseTree{ci.getParsing().parseTree()};
   assert(parseTree && "Cannot run semantic checks without a parse tree!");
 
+  // Transfer any pending non-fatal messages from parsing to semantics
+  // so that they are merged and all printed in order.
+  auto &semanticsCtx{ci.getSemanticsContext()};
+  semanticsCtx.messages().Annex(std::move(ci.getParsing().messages()));
+
   // Prepare semantics
   ci.setSemantics(std::make_unique<Fortran::semantics::Semantics>(
-      ci.getSemanticsContext(), *parseTree,
-      ci.getInvocation().getDebugModuleDir()));
+      semanticsCtx, *parseTree, ci.getInvocation().getDebugModuleDir()));
   auto &semantics = ci.getSemantics();
 
   // Run semantic checks
@@ -187,7 +193,7 @@ bool FrontendAction::runSemanticChecks() {
     return false;
   }
 
-  // Report the diagnostics from the semantic checks
+  // Report the diagnostics from parsing and the semantic checks
   semantics.EmitMessages(ci.getSemaOutputStream());
 
   return true;

flang/lib/Frontend/FrontendActions.cpp

@@ -123,12 +123,12 @@ static bool saveMLIRTempFile(const CompilerInvocation &ci,
 bool PrescanAction::beginSourceFileAction() { return runPrescan(); }
 
 bool PrescanAndParseAction::beginSourceFileAction() {
-  return runPrescan() && runParse();
+  return runPrescan() && runParse(/*emitMessages=*/true);
 }
 
 bool PrescanAndSemaAction::beginSourceFileAction() {
-  return runPrescan() && runParse() && runSemanticChecks() &&
-         generateRtTypeTables();
+  return runPrescan() && runParse(/*emitMessages=*/false) &&
+         runSemanticChecks() && generateRtTypeTables();
 }
 
 bool PrescanAndSemaDebugAction::beginSourceFileAction() {
@@ -137,8 +137,8 @@ bool PrescanAndSemaDebugAction::beginSourceFileAction() {
   // from exiting early (i.e. in the presence of semantic errors). We should
   // never do this in actions intended for end-users or otherwise regular
   // compiler workflows!
-  return runPrescan() && runParse() && (runSemanticChecks() || true) &&
-         (generateRtTypeTables() || true);
+  return runPrescan() && runParse(/*emitMessages=*/false) &&
+         (runSemanticChecks() || true) && (generateRtTypeTables() || true);
 }
 
 static void addDependentLibs(mlir::ModuleOp &mlirModule, CompilerInstance &ci) {
@@ -275,8 +275,8 @@ bool CodeGenAction::beginSourceFileAction() {
     ci.getDiagnostics().Report(diagID);
     return false;
   }
-  bool res = runPrescan() && runParse() && runSemanticChecks() &&
-             generateRtTypeTables();
+  bool res = runPrescan() && runParse(/*emitMessages=*/false) &&
+             runSemanticChecks() && generateRtTypeTables();
   if (!res)
     return res;
 

flang/lib/Semantics/semantics.cpp

@@ -593,7 +593,10 @@ bool Semantics::Perform() {
       ModFileWriter{context_}.WriteAll();
 }
 
-void Semantics::EmitMessages(llvm::raw_ostream &os) const {
+void Semantics::EmitMessages(llvm::raw_ostream &os) {
+  // Resolve the CharBlock locations of the Messages to ProvenanceRanges
+  // so messages from parsing and semantics are intermixed in source order.
+  context_.messages().ResolveProvenances(context_.allCookedSources());
   context_.messages().Emit(os, context_.allCookedSources());
 }
 

flang/test/Driver/message-merging.f90

@@ -0,0 +1,7 @@
+!RUN: %flang -fsyntax-only -pedantic -I %S/Inputs/ %s 2>&1 | FileCheck %s
+!CHECK: warning: SAVE attribute was already specified on 'x'
+!CHECK: portability: #include: extra stuff ignored after file name
+save x
+save x
+#include <empty.h>    crud after header name
+end

flang/tools/bbc/bbc.cpp

@@ -289,17 +289,20 @@ static mlir::LogicalResult convertFortranSourceToMLIR(
 
   // parse the input Fortran
   parsing.Parse(llvm::outs());
-  parsing.messages().Emit(llvm::errs(), parsing.allCooked());
   if (!parsing.consumedWholeFile()) {
+    parsing.messages().Emit(llvm::errs(), parsing.allCooked());
     parsing.EmitMessage(llvm::errs(), parsing.finalRestingPlace(),
                         "parser FAIL (final position)",
                         "error: ", llvm::raw_ostream::RED);
     return mlir::failure();
-  }
-  if ((!parsing.messages().empty() && (parsing.messages().AnyFatalError())) ||
-      !parsing.parseTree().has_value()) {
+  } else if ((!parsing.messages().empty() &&
+              (parsing.messages().AnyFatalError())) ||
+             !parsing.parseTree().has_value()) {
+    parsing.messages().Emit(llvm::errs(), parsing.allCooked());
     llvm::errs() << programPrefix << "could not parse " << path << '\n';
     return mlir::failure();
+  } else {
+    semanticsContext.messages().Annex(std::move(parsing.messages()));
   }
 
   // run semantics