Implement -MG. Fixes PR9613

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134996 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 53 insertions, 8 deletions

diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 9b3e49480e..eb17609d6c 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -242,6 +242,13 @@ void Clang::AddPreprocessingOptions(const Driver &D,
       CmdArgs.push_back("-sys-header-deps");
   }
 
+  if (Args.hasArg(options::OPT_MG)) {
+    if (!A || A->getOption().matches(options::OPT_MD) ||
+              A->getOption().matches(options::OPT_MMD))
+      D.Diag(clang::diag::err_drv_mg_requires_m_or_mm);
+    CmdArgs.push_back("-MG");
+  }
+
   Args.AddLastArg(CmdArgs, options::OPT_MP);
 
   // Convert all -MQ <target> args to -MT <quoted target>
@@ -1354,8 +1361,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   types::ID InputType = Inputs[0].getType();
   if (!Args.hasArg(options::OPT_fallow_unsupported)) {
     Arg *Unsupported;
-    if ((Unsupported = Args.getLastArg(options::OPT_MG)) ||
-        (Unsupported = Args.getLastArg(options::OPT_iframework)))
+    if ((Unsupported = Args.getLastArg(options::OPT_iframework)))
       D.Diag(clang::diag::err_drv_clang_unsupported)
         << Unsupported->getOption().getName();
 
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 02a5088f93..05b3377b3e 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1048,6 +1048,7 @@ static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,
   Opts.UsePhonyTargets = Args.hasArg(OPT_MP);
   Opts.ShowHeaderIncludes = Args.hasArg(OPT_H);
   Opts.HeaderIncludeOutputFile = Args.getLastArgValue(OPT_header_include_file);
+  Opts.AddMissingHeaderDeps = Args.hasArg(OPT_MG);
 }
 
 static void ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,
diff --git a/lib/Frontend/DependencyFile.cpp b/lib/Frontend/DependencyFile.cpp
index dde3454aba..1edd09b06c 100644
--- a/lib/Frontend/DependencyFile.cpp
+++ b/lib/Frontend/DependencyFile.cpp
@@ -17,6 +17,7 @@
 #include "clang/Frontend/DependencyOutputOptions.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Lex/DirectoryLookup.h"
+#include "clang/Lex/LexDiagnostic.h"
 #include "clang/Lex/PPCallbacks.h"
 #include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/StringSet.h"
@@ -34,9 +35,11 @@ class DependencyFileCallback : public PPCallbacks {
   llvm::raw_ostream *OS;
   bool IncludeSystemHeaders;
   bool PhonyTarget;
+  bool AddMissingHeaderDeps;
 private:
   bool FileMatchesDepCriteria(const char *Filename,
                               SrcMgr::CharacteristicKind FileType);
+  void AddFilename(llvm::StringRef Filename);
   void OutputDependencyFile();
 
 public:
@@ -45,10 +48,19 @@ public:
                          const DependencyOutputOptions &Opts)
     : PP(_PP), Targets(Opts.Targets), OS(_OS),
       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
-      PhonyTarget(Opts.UsePhonyTargets) {}
+      PhonyTarget(Opts.UsePhonyTargets),
+      AddMissingHeaderDeps(Opts.AddMissingHeaderDeps) {}
 
   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                            SrcMgr::CharacteristicKind FileType);
+  virtual void InclusionDirective(SourceLocation HashLoc,
+                                  const Token &IncludeTok,
+                                  llvm::StringRef FileName,
+                                  bool IsAngled,
+                                  const FileEntry *File,
+                                  SourceLocation EndLoc,
+                                  llvm::StringRef SearchPath,
+                                  llvm::StringRef RelativePath);
 
   virtual void EndOfMainFile() {
     OutputDependencyFile();
@@ -73,6 +85,16 @@ void clang::AttachDependencyFileGen(Preprocessor &PP,
     return;
   }
 
+  // Disable the "file not found" diagnostic if the -MG option was given.
+  // FIXME: Ideally this would live in the driver, but we don't have the ability
+  // to remap individual diagnostics there without creating a DiagGroup, in
+  // which case we would need to prevent the group name from showing up in
+  // diagnostics.
+  if (Opts.AddMissingHeaderDeps) {
+    PP.getDiagnostics().setDiagnosticMapping(diag::warn_pp_file_not_found,
+                                            diag::MAP_IGNORE, SourceLocation());
+  }
+
   PP.addPPCallbacks(new DependencyFileCallback(&PP, OS, Opts));
 }
 
@@ -116,7 +138,22 @@ void DependencyFileCallback::FileChanged(SourceLocation Loc,
       Filename = Filename.substr(1);
   }
     
+  AddFilename(Filename);
+}
+
+void DependencyFileCallback::InclusionDirective(SourceLocation HashLoc,
+                                                const Token &IncludeTok,
+                                                llvm::StringRef FileName,
+                                                bool IsAngled,
+                                                const FileEntry *File,
+                                                SourceLocation EndLoc,
+                                                llvm::StringRef SearchPath,
+                                                llvm::StringRef RelativePath) {
+  if (AddMissingHeaderDeps && !File)
+    AddFilename(FileName);
+}
 
+void DependencyFileCallback::AddFilename(llvm::StringRef Filename) {
   if (FilesSet.insert(Filename))
     Files.push_back(Filename);
 }
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index efa188f752..4af5fabe5c 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -1180,16 +1180,17 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
   const FileEntry *File = LookupFile(
       Filename, isAngled, LookupFrom, CurDir,
       Callbacks ? &SearchPath : NULL, Callbacks ? &RelativePath : NULL);
-  if (File == 0) {
-    Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
-    return;
-  }
 
   // Notify the callback object that we've seen an inclusion directive.
   if (Callbacks)
     Callbacks->InclusionDirective(HashLoc, IncludeTok, Filename, isAngled, File,
                                   End, SearchPath, RelativePath);
 
+  if (File == 0) {
+    Diag(FilenameTok, diag::warn_pp_file_not_found) << Filename;
+    return;
+  }
+
   // The #included file will be considered to be a system header if either it is
   // in a system include directory, or if the #includer is a system include
   // header.
diff --git a/lib/Lex/Pragma.cpp b/lib/Lex/Pragma.cpp
index bd2ac1b6fb..e6b28c1331 100644
--- a/lib/Lex/Pragma.cpp
+++ b/lib/Lex/Pragma.cpp
@@ -368,7 +368,7 @@ void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
   const DirectoryLookup *CurDir;
   const FileEntry *File = LookupFile(Filename, isAngled, 0, CurDir, NULL, NULL);
   if (File == 0) {
-    Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    Diag(FilenameTok, diag::warn_pp_file_not_found) << Filename;
     return;
   }