Implements support for #pragma include_alias in ms compatibility mode. Fixes PR10705.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151800 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 157 insertions, 0 deletions

diff --git a/include/clang/Basic/DiagnosticLexKinds.td b/include/clang/Basic/DiagnosticLexKinds.td
index 46e0bebb3e..d7ed55a81f 100644
--- a/include/clang/Basic/DiagnosticLexKinds.td
+++ b/include/clang/Basic/DiagnosticLexKinds.td
@@ -292,6 +292,15 @@ def warn_has_warning_invalid_option :
    ExtWarn<"__has_warning expected option name (e.g. \"-Wundef\")">,
    InGroup<MalformedWarningCheck>;
 
+def warn_pragma_include_alias_mismatch :
+   ExtWarn<"pragma include_alias requires matching include directives "
+   "(e.g include_alias(\"foo.h\", \"bar.h\") or "
+   "include_alias(<foo.h>, <bar.h>))">,
+   InGroup<UnknownPragmas>;
+def warn_pragma_include_alias_expected :
+   ExtWarn<"pragma include_alias expected '%0'">,
+   InGroup<UnknownPragmas>;
+
 def err__Pragma_malformed : Error<
   "_Pragma takes a parenthesized string literal">;
 def err_pragma_comment_malformed : Error<
diff --git a/include/clang/Lex/HeaderSearch.h b/include/clang/Lex/HeaderSearch.h
index 84bb37da3a..bbd7146cf4 100644
--- a/include/clang/Lex/HeaderSearch.h
+++ b/include/clang/Lex/HeaderSearch.h
@@ -154,6 +154,9 @@ class HeaderSearch {
   llvm::StringMap<const DirectoryEntry *, llvm::BumpPtrAllocator>
     FrameworkMap;
 
+  llvm::StringMap<std::pair<StringRef, bool>, llvm::BumpPtrAllocator>
+    IncludeAliasMap;
+
   /// HeaderMaps - This is a mapping from FileEntry -> HeaderMap, uniquing
   /// headermaps.  This vector owns the headermap.
   std::vector<std::pair<const FileEntry*, const HeaderMap*> > HeaderMaps;
@@ -217,6 +220,25 @@ public:
     SystemDirIdx++;
   }
 
+  /// AddHeaderMapping -- Map the source include name to the dest include name
+  void AddHeaderMapping(const StringRef& Source, const StringRef& Dest, 
+                        bool IsAngled) {
+    IncludeAliasMap[Source] = std::make_pair(Dest, IsAngled);
+  }
+
+  StringRef MapHeader(const StringRef& Source, bool isAngled) {
+    // Do any filename replacements before anything else
+    llvm::StringMap<std::pair<StringRef,bool>>::const_iterator iter = 
+      IncludeAliasMap.find(Source);
+    if (iter != IncludeAliasMap.end()) {
+      // If the angling matches, then we've found a replacement
+      if (iter->second.second == isAngled) {
+        return iter->second.first;
+      }
+    }
+    return Source;
+  }
+
   /// \brief Set the path to the module cache.
   void setModuleCachePath(StringRef CachePath) {
     ModuleCachePath = CachePath;
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index feed6a8bfa..9ee9e82529 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -1262,6 +1262,7 @@ public:
   void HandlePragmaMessage(Token &MessageTok);
   void HandlePragmaPushMacro(Token &Tok);
   void HandlePragmaPopMacro(Token &Tok);
+  void HandlePragmaIncludeAlias(Token &Tok);
   IdentifierInfo *ParsePragmaPushOrPopMacro(Token &Tok);
 
   // Return true and store the first token only if any CommentHandler
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index 0364e4279a..4839dfa4a1 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -1304,6 +1304,9 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
     PragmaARCCFCodeAuditedLoc = SourceLocation();
   }
 
+  // Map the filename
+  Filename = HeaderInfo.MapHeader(Filename, isAngled);
+
   // Search include directories.
   const DirectoryLookup *CurDir;
   SmallString<1024> SearchPath;
diff --git a/lib/Lex/Pragma.cpp b/lib/Lex/Pragma.cpp
index 503fffe53d..7a6ab7dd72 100644
--- a/lib/Lex/Pragma.cpp
+++ b/lib/Lex/Pragma.cpp
@@ -663,6 +663,101 @@ void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
   }
 }
 
+void Preprocessor::HandlePragmaIncludeAlias(Token& Tok) {
+  // We will either get a quoted filename or a bracketed filename, and we 
+  // have to track which we got.  The first filename is the source name,
+  // and the second name is the mapped filename.  If the first is quoted,
+  // the second must be as well (cannot mix and match quotes and brackets).
+  SourceLocation Loc = Tok.getLocation();
+
+  // Get the open paren
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << "(";
+    return;
+  }
+
+  // We expect either a quoted string literal, or a bracketed name
+  Token SourceFilenameTok;
+  CurPPLexer->LexIncludeFilename(SourceFilenameTok);
+  if (SourceFilenameTok.is(tok::eod)) {
+    // The diagnostic has already been handled
+    return;
+  }
+
+  StringRef SourceFileName;
+  SmallString<128> FileNameBuffer;
+  if (SourceFilenameTok.is(tok::string_literal) || 
+      SourceFilenameTok.is(tok::angle_string_literal)) {
+    SourceFileName = getSpelling(SourceFilenameTok, FileNameBuffer);
+  } else if (SourceFilenameTok.is(tok::less)) {
+    // This could be a path instead of just a name
+    FileNameBuffer.push_back('<');
+    SourceLocation End;
+    if (ConcatenateIncludeName(FileNameBuffer, End))
+      return; // Diagnostic already emitted
+    SourceFileName = FileNameBuffer.str();
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << "include filename";
+    return;
+  }
+  FileNameBuffer.clear();
+
+  // Now we expect a comma, followed by another include name
+  Lex(Tok);
+  if (Tok.isNot(tok::comma)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ",";
+    return;
+  }
+
+  Token ReplaceFilenameTok;
+  CurPPLexer->LexIncludeFilename(ReplaceFilenameTok);
+  if (ReplaceFilenameTok.is(tok::eod)) {
+    // The diagnostic has already been handled
+    return;
+  }
+
+  StringRef ReplaceFileName;
+  if (ReplaceFilenameTok.is(tok::string_literal) || 
+      ReplaceFilenameTok.is(tok::angle_string_literal)) {
+    ReplaceFileName = getSpelling(ReplaceFilenameTok, FileNameBuffer);
+  } else if (ReplaceFilenameTok.is(tok::less)) {
+    // This could be a path instead of just a name
+    FileNameBuffer.push_back('<');
+    SourceLocation End;
+    if (ConcatenateIncludeName(FileNameBuffer, End))
+      return; // Diagnostic already emitted
+    ReplaceFileName = FileNameBuffer.str();
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << "include filename";
+    return;
+  }
+
+  // Finally, we expect the closing paren
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ")";
+    return;
+  }
+
+  // Now that we have the source and target filenames, we need to make sure
+  // they're both of the same type (angled vs non-angled)
+  bool SourceIsAngled = 
+    GetIncludeFilenameSpelling(SourceFilenameTok.getLocation(), 
+                                SourceFileName);
+  bool ReplaceIsAngled =
+    GetIncludeFilenameSpelling(ReplaceFilenameTok.getLocation(),
+                                ReplaceFileName);
+  if (SourceIsAngled != ReplaceIsAngled) {
+    Diag(Loc, diag::warn_pragma_include_alias_mismatch);
+    return;
+  }
+
+  // Now we can let the include handler know about this mapping
+  getHeaderSearchInfo().AddHeaderMapping(SourceFileName, ReplaceFileName, 
+                                          SourceIsAngled);
+}
+
 /// AddPragmaHandler - Add the specified pragma handler to the preprocessor.
 /// If 'Namespace' is non-null, then it is a token required to exist on the
 /// pragma line before the pragma string starts, e.g. "STDC" or "GCC".
@@ -943,6 +1038,15 @@ struct PragmaCommentHandler : public PragmaHandler {
   }
 };
 
+/// PragmaIncludeAliasHandler - "#pragma include_alias("...")".
+struct PragmaIncludeAliasHandler : public PragmaHandler {
+  PragmaIncludeAliasHandler() : PragmaHandler("include_alias") {}
+  virtual void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
+                            Token &IncludeAliasTok) {
+      PP.HandlePragmaIncludeAlias(IncludeAliasTok);
+  }
+};
+
 /// PragmaMessageHandler - "#pragma message("...")".
 struct PragmaMessageHandler : public PragmaHandler {
   PragmaMessageHandler() : PragmaHandler("message") {}
@@ -1095,5 +1199,6 @@ void Preprocessor::RegisterBuiltinPragmas() {
   // MS extensions.
   if (Features.MicrosoftExt) {
     AddPragmaHandler(new PragmaCommentHandler());
+    AddPragmaHandler(new PragmaIncludeAliasHandler());
   }
 }
diff --git a/test/Preprocessor/pragma_microsoft.c b/test/Preprocessor/pragma_microsoft.c
index b68d6e363e..88925ffdb2 100644
--- a/test/Preprocessor/pragma_microsoft.c
+++ b/test/Preprocessor/pragma_microsoft.c
@@ -38,3 +38,20 @@ void f()
   // this warning should go away.
   MACRO_WITH__PRAGMA // expected-warning {{expression result unused}}
 }
+
+
+// This should include macro_arg_directive even though the include
+// is looking for test.h  This allows us to assign to "n"
+#pragma include_alias("test.h", "macro_arg_directive.h" )
+#include "test.h"
+void test( void ) {
+  n = 12;
+}
+
+#pragma include_alias("foo.h", <bar.h>) // expected-warning {{pragma include_alias requires matching include directives (e.g include_alias("foo.h", "bar.h") or include_alias(<foo.h>, <bar.h>))}}
+#pragma include_alias("test.h") // expected-warning {{pragma include_alias expected ','}}
+
+// Make sure that the names match exactly for a replacement, including path information.  If
+// this were to fail, we would get a file not found error
+#pragma include_alias(".\pp-record.h", "does_not_exist.h")
+#include "pp-record.h"