[cfe-commits] [PATCH] Support for pragma include_alias
Argyrios Kyrtzidis
kyrtzidis at apple.com
Fri Mar 2 10:54:10 PST 2012
On Mar 2, 2012, at 9:51 AM, Aaron Ballman wrote:
> On Thu, Mar 1, 2012 at 8:07 PM, Argyrios Kyrtzidis <kyrtzidis at apple.com> wrote:
>> On Mar 1, 2012, at 10:43 AM, Aaron Ballman wrote:
>>
>>> On Thu, Mar 1, 2012 at 12:21 AM, Richard Smith <richard at metafoo.co.uk> wrote:
>>>> Hi,
>>>>
>>>>>> On Sun, Feb 19, 2012 at 5:31 PM, Aaron Ballman <aaron at aaronballman.com>
>>>>>> wrote:
>>>>>>> One of the MSVC pragmas is the ability to remap include filenames, as
>>>>>>> described in MSDN:
>>>>>>> http://msdn.microsoft.com/en-us/library/wbeh5h91.aspx
>>>>>>>
>>>>>>> The long and short of it is: you can use this pragma to map the source
>>>>>>> filename to a replacement filename (usually for supporting the old 8.3
>>>>>>> filenames on FAT systems, but can be used arbitrarily). For instance:
>>>>>>>
>>>>>>> #pragma include_alias( "FoobarIsReallyLong.h", "FOOBAR~1.H" )
>>>>>>> #include "FoobarIsReallyLong.h" // Actually opens up FOOBAR~1.H
>>>>>>>
>>>>>>> #pragma include_alias( <foo.h>, <bar.h> )
>>>>>>> #include <foo.h> // Actually includes <bar.h>
>>>>>>> #include "foo.h" // Still includes "foo.h"
>>>>>>>
>>>>>>> This patch implements that pragma, and closes Bug 10705.
>>>>
>>>>
>>>> Sorry for the delay!
>>>>
>>>>> Index: include/clang/Basic/DiagnosticLexKinds.td
>>>>> ===================================================================
>>>>> --- include/clang/Basic/DiagnosticLexKinds.td (revision 150897)
>>>>> +++ include/clang/Basic/DiagnosticLexKinds.td (working copy)
>>>>> @@ -292,6 +292,15 @@
>>>>> 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>;
>>>>
>>>> Can we make this diagnostic clearer? I'd prefer for us to produce different
>>>> text depending on whether the source include was a "include" or a <include>.
>>>> As a first pass:
>>>>
>>>> angle-bracketed include <%0> cannot be aliased to double-quoted include "%1"
>>>> double-quoted include "%0" cannot be aliased to angle-bracketed include <%1>
>>>>
>>>>> +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<
>>>>> Index: include/clang/Lex/HeaderSearch.h
>>>>> ===================================================================
>>>>> --- include/clang/Lex/HeaderSearch.h (revision 150897)
>>>>> +++ include/clang/Lex/HeaderSearch.h (working copy)
>>>>> @@ -154,6 +154,9 @@
>>>>> llvm::StringMap<const DirectoryEntry *, llvm::BumpPtrAllocator>
>>>>> FrameworkMap;
>>>>>
>>>>> + llvm::StringMap<std::pair<StringRef, bool>, llvm::BumpPtrAllocator>
>>>>> + IncludeAliasMap;
>>>>
>>>> This map doesn't appear to be sufficient: the Microsoft documentation
>>>> indicates that "foo" and <foo> can be aliased to different includes.
>>>>
>>>> Also, the StringRef in the value type here will refer to a string whose
>>>> lifetime has ended.
>>>>
>>>>> +
>>>>> /// 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 @@
>>>>> SystemDirIdx++;
>>>>> }
>>>>>
>>>>> + /// AddHeaderMapping -- Map the source include name to the dest include
>>>>> name
>>>>> + void AddHeaderMapping(const StringRef& Source, const StringRef& Dest,
>>>>
>>>> Generally, please write " &" not "& ". Also, StringRefs are usually passed
>>>> by value.
>>>>
>>>>> + 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 =
>>>>
>>>> Please capitalize IsAngled and Iter, and write "> >" not ">>". I don't like
>>>> repeating this type here (and especially not missing out the
>>>> llvm::BumpPtrAllocator argument); consider adding a typedef for your
>>>> container type.
>>>>
>>>>> + 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;
>>>>> + }
>>>>
>>>> Prevailing llvm/clang style is to omit the braces around a simple
>>>> single-statement body such as this.
>>>>
>>>>> + }
>>>>> + return Source;
>>>>> + }
>>>>> +
>>>>> /// \brief Set the path to the module cache.
>>>>> void setModuleCachePath(StringRef CachePath) {
>>>>> ModuleCachePath = CachePath;
>>>>> Index: include/clang/Lex/Preprocessor.h
>>>>> ===================================================================
>>>>> --- include/clang/Lex/Preprocessor.h (revision 150897)
>>>>> +++ include/clang/Lex/Preprocessor.h (working copy)
>>>>> @@ -1262,6 +1262,7 @@
>>>>> 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
>>>>> Index: lib/Lex/PPDirectives.cpp
>>>>> ===================================================================
>>>>> --- lib/Lex/PPDirectives.cpp (revision 150897)
>>>>> +++ lib/Lex/PPDirectives.cpp (working copy)
>>>>> @@ -1297,6 +1297,9 @@
>>>>> PragmaARCCFCodeAuditedLoc = SourceLocation();
>>>>> }
>>>>>
>>>>> + // Map the filename
>>>>> + Filename = HeaderInfo.MapHeader(Filename, isAngled);
>>>>> +
>>>>> // Search include directories.
>>>>> const DirectoryLookup *CurDir;
>>>>> SmallString<1024> SearchPath;
>>>>> Index: lib/Lex/Pragma.cpp
>>>>> ===================================================================
>>>>> --- lib/Lex/Pragma.cpp (revision 150897)
>>>>> +++ lib/Lex/Pragma.cpp (working copy)
>>>>> @@ -663,6 +663,101 @@
>>>>> }
>>>>> }
>>>>>
>>>>> +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";
>>>>
>>>> English phrases shouldn't be used as diagnostic arguments, since they won't
>>>> be translatable (if we ever choose to translate the diagnostics). Please use
>>>> a different diagnostic for this; perhaps diag::err_pp_expects_filename?
>>>>
>>>> Also, I don't see a test for this error.
>>>>
>>>>> + 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;
>>>>> + }
>>>>
>>>> Could this repeated code be factored out? (I imagine we have largely the
>>>> same pattern in some other places too.)
>>>>
>>>>> +
>>>>> + // 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,
>>>>
>>>> ReplaceFileName here refers to a string which expires at the end of this
>>>> function, and it's being saved away by AddHeaderMapping for later use.
>>>>
>>>>> + 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 @@
>>>>> }
>>>>> };
>>>>>
>>>>> +/// 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 @@
>>>>> // MS extensions.
>>>>> if (Features.MicrosoftExt) {
>>>>> AddPragmaHandler(new PragmaCommentHandler());
>>>>> + AddPragmaHandler(new PragmaIncludeAliasHandler());
>>>>> }
>>>>> }
>>>>> Index: test/Preprocessor/pragma_microsoft.c
>>>>> ===================================================================
>>>>> --- test/Preprocessor/pragma_microsoft.c (revision 150897)
>>>>> +++ test/Preprocessor/pragma_microsoft.c (working copy)
>>>>> @@ -38,3 +38,20 @@
>>>>> // 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"
>>>>
>>>
>>> Hi Richard -- I've addressed almost all of the points in your review,
>>> and have attached a patch for you to check over again. Thank you for
>>> all the helpful feedback!
>>>
>>> The only thing I didn't address was:
>>>
>>>> Could this repeated code be factored out? (I imagine we have largely the
>>>> same pattern in some other places too.)
>>>
>>> I'm guessing the code could be refactored out, but I'd rather that be
>>> a separate patch since it touches on more than just include_alias.
>>>
>>> Thanks!
>>
>> A few additional comments, I suggest optimizing for the common path, that there is no include_alias in the source, so:
>>
>> + typedef llvm::StringMap<std::string, llvm::BumpPtrAllocator>
>> + IncludeAliasMap;
>> + IncludeAliasMap IncludeAliases;
>>
>> Have this be a pointer and create the object lazily on demand:
>> OwningPtr<IncludeAliasMap> IncludeAliases;
>>
>> + // Map the filename with the brackets still attached. If the name doesn't
>> + // map to anything, fall back on the filename we've already gotten the
>> + // spelling for.
>> + std::string NewName = HeaderInfo.MapHeader(OriginalFilename);
>> + if (!NewName.empty())
>> + Filename = NewName;
>> +
>>
>> here you can check if the object was created or not before going ahead to call HeaderInfo.MapHeader(OriginalFilename).
>>
>> + void AddHeaderMapping(StringRef Source, StringRef Dest) {
>> and
>> + std::string MapHeader(StringRef Source) {
>>
>> Rename to "AddIncludeAlias" and "MapHeaderToIncludeAlias" to make clear what these are for ?
>
> Thanks for the reviews -- I've attached a patch with your suggestions
> incorporated. I've cleaned up the items Richard pointed out, and made
> the alias mapping lazy-loaded as Argyrios suggested.
Thanks Aaron. Another thing I'd like to bring to your attention:
Since all the include_alias related methods are only used by the preprocessor, how about moving the methods and IncludeAliases object to the Preprocessor and make them all private ?
I'd prefer if such esoteric extensions were isolated and hidden away as much as possible, like in a dark dungeon :-)
>
> Thanks!
>
> ~Aaron
> <include_alias.patch>
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