Method loadFromCommandLine should be able to report errors

Now FixedCompilationDatabase::loadFromCommandLine has no means to report
which error occurred if it fails to create compilation object. This is
a block for implementing D33013, because after that change driver will
refuse to create compilation if command line contains erroneous options.

This change adds additional argument to loadFromCommandLine, which is
assigned error message text if compilation object was not created. This is
the same way as other methods of CompilationDatabase report failure.

Differential Revision: https://reviews.llvm.org/D33272

llvm-svn: 303741

1 files changed, 26 insertions, 16 deletions

diff --git a/clang/lib/Tooling/CompilationDatabase.cpp b/clang/lib/Tooling/CompilationDatabase.cpp
index 8ca0b2d..77c5b54 100644
--- a/clang/lib/Tooling/CompilationDatabase.cpp
+++ b/clang/lib/Tooling/CompilationDatabase.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Option/Arg.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
 #include <sstream>
 #include <system_error>
 using namespace clang;
@@ -150,23 +151,21 @@ private:
 // options.
 class UnusedInputDiagConsumer : public DiagnosticConsumer {
 public:
-  UnusedInputDiagConsumer() : Other(nullptr) {}
-
-  // Useful for debugging, chain diagnostics to another consumer after
-  // recording for our own purposes.
-  UnusedInputDiagConsumer(DiagnosticConsumer *Other) : Other(Other) {}
+  UnusedInputDiagConsumer(DiagnosticConsumer &Other) : Other(Other) {}
 
   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
                         const Diagnostic &Info) override {
     if (Info.getID() == clang::diag::warn_drv_input_file_unused) {
       // Arg 1 for this diagnostic is the option that didn't get used.
       UnusedInputs.push_back(Info.getArgStdStr(0));
+    } else if (DiagLevel >= DiagnosticsEngine::Error) {
+      // If driver failed to create compilation object, show the diagnostics
+      // to user.
+      Other.HandleDiagnostic(DiagLevel, Info);
     }
-    if (Other)
-      Other->HandleDiagnostic(DiagLevel, Info);
   }
 
-  DiagnosticConsumer *Other;
+  DiagnosticConsumer &Other;
   SmallVector<std::string, 2> UnusedInputs;
 };
 
@@ -205,9 +204,12 @@ private:
 ///          \li false if \c Args cannot be used for compilation jobs (e.g.
 ///          contains an option like -E or -version).
 static bool stripPositionalArgs(std::vector<const char *> Args,
-                                std::vector<std::string> &Result) {
+                                std::vector<std::string> &Result,
+                                std::string &ErrorMsg) {
   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
-  UnusedInputDiagConsumer DiagClient;
+  llvm::raw_string_ostream Output(ErrorMsg);
+  TextDiagnosticPrinter DiagnosticPrinter(Output, &*DiagOpts);
+  UnusedInputDiagConsumer DiagClient(DiagnosticPrinter);
   DiagnosticsEngine Diagnostics(
       IntrusiveRefCntPtr<clang::DiagnosticIDs>(new DiagnosticIDs()),
       &*DiagOpts, &DiagClient, false);
@@ -245,6 +247,8 @@ static bool stripPositionalArgs(std::vector<const char *> Args,
 
   const std::unique_ptr<driver::Compilation> Compilation(
       NewDriver->BuildCompilation(Args));
+  if (!Compilation)
+    return false;
 
   const driver::JobList &Jobs = Compilation->getJobs();
 
@@ -258,8 +262,7 @@ static bool stripPositionalArgs(std::vector<const char *> Args,
   }
 
   if (CompileAnalyzer.Inputs.empty()) {
-    // No compile jobs found.
-    // FIXME: Emit a warning of some kind?
+    ErrorMsg = "warning: no compile jobs found\n";
     return false;
   }
 
@@ -280,8 +283,14 @@ static bool stripPositionalArgs(std::vector<const char *> Args,
   return true;
 }
 
-FixedCompilationDatabase *FixedCompilationDatabase::loadFromCommandLine(
-    int &Argc, const char *const *Argv, Twine Directory) {
+std::unique_ptr<FixedCompilationDatabase>
+FixedCompilationDatabase::loadFromCommandLine(int &Argc,
+                                              const char *const *Argv,
+                                              std::string &ErrorMsg,
+                                              Twine Directory) {
+  ErrorMsg.clear();
+  if (Argc == 0)
+    return nullptr;
   const char *const *DoubleDash = std::find(Argv, Argv + Argc, StringRef("--"));
   if (DoubleDash == Argv + Argc)
     return nullptr;
@@ -289,9 +298,10 @@ FixedCompilationDatabase *FixedCompilationDatabase::loadFromCommandLine(
   Argc = DoubleDash - Argv;
 
   std::vector<std::string> StrippedArgs;
-  if (!stripPositionalArgs(CommandLine, StrippedArgs))
+  if (!stripPositionalArgs(CommandLine, StrippedArgs, ErrorMsg))
     return nullptr;
-  return new FixedCompilationDatabase(Directory, StrippedArgs);
+  return std::unique_ptr<FixedCompilationDatabase>(
+      new FixedCompilationDatabase(Directory, StrippedArgs));
 }
 
 FixedCompilationDatabase::