Support generating NMake/Jom-style depfiles.

NMake is a Make-like builder that comes with Microsoft Visual Studio.
Jom (https://wiki.qt.io/Jom) is an NMake-compatible build tool.
Dependency files for NMake/Jom need to use double-quotes to wrap
filespecs containing special characters, instead of the backslash
escapes that GNU Make wants.

Adds the -MV option, which specifies to use double-quotes as needed
instead of backslash escapes when writing the dependency file.

Differential Revision: http://reviews.llvm.org/D9260


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@235903 91177308-0d34-0410-b5e6-96231b3b80d8

docs/UsersManual.rst

@@ -589,6 +589,25 @@ Current limitations
    translated from debug annotations. That translation can be lossy,
    which results in some remarks having no location information.
 
+Other Options
+-------------
+Clang options that that don't fit neatly into other categories.
+
+.. option:: -MV
+
+  When emitting a dependency file, use formatting conventions appropriate
+  for NMake or Jom. Ignored unless another option causes Clang to emit a
+  dependency file.
+
+When Clang emits a dependency file (e.g., you supplied the -M option)
+most filenames can be written to the file without any special formatting.
+Different Make tools will treat different sets of characters as "special"
+and use different conventions for telling the Make tool that the character
+is actually part of the filename. Normally Clang uses backslash to "escape"
+a special character, which is the convention used by GNU Make. The -MV
+option tells Clang to put double-quotes around the entire filename, which
+is the convention used by NMake and Jom.
+
 
 Language and Target-Independent Features
 ========================================

include/clang/Driver/Options.td

@@ -250,6 +250,8 @@ def MQ : JoinedOrSeparate<["-"], "MQ">, Group<M_Group>, Flags<[CC1Option]>,
     HelpText<"Specify name of main file output to quote in depfile">;
 def MT : JoinedOrSeparate<["-"], "MT">, Group<M_Group>, Flags<[CC1Option]>,
     HelpText<"Specify name of main file output in depfile">;
+def MV : Flag<["-"], "MV">, Group<M_Group>, Flags<[CC1Option]>,
+    HelpText<"Use NMake/Jom format for the depfile">;
 def Mach : Flag<["-"], "Mach">;
 def O0 : Flag<["-"], "O0">, Group<O_Group>, Flags<[CC1Option]>;
 def O4 : Flag<["-"], "O4">, Group<O_Group>, Flags<[CC1Option]>;

include/clang/Frontend/DependencyOutputOptions.h

@@ -15,6 +15,9 @@
 
 namespace clang {
 
+/// DependencyOutputFormat - Format for the compiler dependency file.
+enum class DependencyOutputFormat { Make, NMake };
+
 /// DependencyOutputOptions - Options for controlling the compiler dependency
 /// file generation.
 class DependencyOutputOptions {
@@ -27,7 +30,10 @@ public:
   unsigned AddMissingHeaderDeps : 1; ///< Add missing headers to dependency list
   unsigned PrintShowIncludes : 1; ///< Print cl.exe style /showIncludes info.
   unsigned IncludeModuleFiles : 1; ///< Include module file dependencies.
-  
+
+  /// The format for the dependency file.
+  DependencyOutputFormat OutputFormat;
+
   /// The file to write dependency output to.
   std::string OutputFile;
 
@@ -55,6 +61,7 @@ public:
     AddMissingHeaderDeps = 0;
     PrintShowIncludes = 0;
     IncludeModuleFiles = 0;
+    OutputFormat = DependencyOutputFormat::Make;
   }
 };
 

lib/Driver/Tools.cpp

@@ -338,6 +338,7 @@ void Clang::AddPreprocessingOptions(Compilation &C,
   }
 
   Args.AddLastArg(CmdArgs, options::OPT_MP);
+  Args.AddLastArg(CmdArgs, options::OPT_MV);
 
   // Convert all -MQ <target> args to -MT <quoted target>
   for (arg_iterator it = Args.filtered_begin(options::OPT_MT,

lib/Frontend/CompilerInvocation.cpp

@@ -661,6 +661,8 @@ static void ParseDependencyOutputArgs(DependencyOutputOptions &Opts,
   Opts.DOTOutputFile = Args.getLastArgValue(OPT_dependency_dot);
   Opts.ModuleDependencyOutputDir =
       Args.getLastArgValue(OPT_module_dependency_dir);
+  if (Args.hasArg(OPT_MV))
+    Opts.OutputFormat = DependencyOutputFormat::NMake;
 }
 
 bool clang::ParseDiagnosticArgs(DiagnosticOptions &Opts, ArgList &Args,

lib/Frontend/DependencyFile.cpp

@@ -150,6 +150,8 @@ class DFGImpl : public PPCallbacks {
   bool AddMissingHeaderDeps;
   bool SeenMissingHeader;
   bool IncludeModuleFiles;
+  DependencyOutputFormat OutputFormat;
+
 private:
   bool FileMatchesDepCriteria(const char *Filename,
                               SrcMgr::CharacteristicKind FileType);
@@ -162,7 +164,8 @@ public:
       PhonyTarget(Opts.UsePhonyTargets),
       AddMissingHeaderDeps(Opts.AddMissingHeaderDeps),
       SeenMissingHeader(false),
-      IncludeModuleFiles(Opts.IncludeModuleFiles) {}
+      IncludeModuleFiles(Opts.IncludeModuleFiles),
+      OutputFormat(Opts.OutputFormat) {}
 
   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                    SrcMgr::CharacteristicKind FileType,
@@ -290,8 +293,23 @@ void DFGImpl::AddFilename(StringRef Filename) {
 }
 
 /// PrintFilename - GCC escapes spaces, # and $, but apparently not ' or " or
-/// other scary characters.
-static void PrintFilename(raw_ostream &OS, StringRef Filename) {
+/// other scary characters. NMake/Jom has a different set of scary characters,
+/// but wraps filespecs in double-quotes to avoid misinterpreting them;
+/// https://msdn.microsoft.com/en-us/library/dd9y37ha.aspx for NMake info,
+/// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
+/// for Windows file-naming info.
+static void PrintFilename(raw_ostream &OS, StringRef Filename,
+                          DependencyOutputFormat OutputFormat) {
+  if (OutputFormat == DependencyOutputFormat::NMake) {
+    // Add quotes if needed. These are the characters listed as "special" to
+    // NMake, that are legal in a Windows filespec, and that could cause
+    // misinterpretation of the dependency string.
+    if (Filename.find_first_of(" #${}^!") != StringRef::npos)
+      OS << '\"' << Filename << '\"';
+    else
+      OS << Filename;
+    return;
+  }
   for (unsigned i = 0, e = Filename.size(); i != e; ++i) {
     if (Filename[i] == ' ' || Filename[i] == '#')
       OS << '\\';
@@ -354,7 +372,7 @@ void DFGImpl::OutputDependencyFile() {
       Columns = 2;
     }
     OS << ' ';
-    PrintFilename(OS, *I);
+    PrintFilename(OS, *I, OutputFormat);
     Columns += N + 1;
   }
   OS << '\n';
@@ -365,7 +383,7 @@ void DFGImpl::OutputDependencyFile() {
     for (std::vector<std::string>::iterator I = Files.begin() + 1,
            E = Files.end(); I != E; ++I) {
       OS << '\n';
-      PrintFilename(OS, *I);
+      PrintFilename(OS, *I, OutputFormat);
       OS << ":\n";
     }
   }

test/Frontend/dependency-gen-escaping.c

@@ -4,13 +4,22 @@
 // RUN: echo > '%t.dir/    .h'
 // RUN: echo > '%t.dir/$$.h'
 // RUN: echo > '%t.dir/##.h'
+// RUN: echo > '%t.dir/normal.h'
 // RUN: cd %t.dir
 // RUN: %clang -MD -MF - %s -fsyntax-only -I. | FileCheck -strict-whitespace %s
+// RUN: %clang -MD -MF - -MV %s -fsyntax-only -I. | FileCheck -strict-whitespace %s --check-prefix=QUOTE
 
 // CHECK: \ \ \ \ .h
 // CHECK: $$$$.h
 // CHECK: \#\#.h
+// QUOTE: "    .h"
+// QUOTE: "$$.h"
+// QUOTE: "##.h"
+// QUOTE-NOT: "
+// QUOTE: normal.h
+// QUOTE-NOT: "
 
 #include "    .h"
 #include "$$.h"
 #include "##.h"
+#include "normal.h"