Introduce builtin macros to determine whether we're building a
specific module (__building_module(modulename)) and to get the name of
the current module as an identifier (__MODULE__).
Used to help headers behave differently when they're being included as
part of building a module. Oh, the irony.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164605 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 839cec0..b2d5977 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -105,6 +105,20 @@
Ident__has_include_next = RegisterBuiltinMacro(*this, "__has_include_next");
Ident__has_warning = RegisterBuiltinMacro(*this, "__has_warning");
+ // Modules.
+ if (LangOpts.Modules) {
+ Ident__building_module = RegisterBuiltinMacro(*this, "__building_module");
+
+ // __MODULE__
+ if (!LangOpts.CurrentModule.empty())
+ Ident__MODULE__ = RegisterBuiltinMacro(*this, "__MODULE__");
+ else
+ Ident__MODULE__ = 0;
+ } else {
+ Ident__building_module = 0;
+ Ident__MODULE__ = 0;
+ }
+
// Microsoft Extensions.
if (LangOpts.MicrosoftExt)
Ident__pragma = RegisterBuiltinMacro(*this, "__pragma");
@@ -907,6 +921,47 @@
return EvaluateHasIncludeCommon(Tok, II, PP, Lookup);
}
+/// \brief Process __building_module(identifier) expression.
+/// \returns true if we are building the named module, false otherwise.
+static bool EvaluateBuildingModule(Token &Tok,
+ IdentifierInfo *II, Preprocessor &PP) {
+ // Get '('.
+ PP.LexNonComment(Tok);
+
+ // Ensure we have a '('.
+ if (Tok.isNot(tok::l_paren)) {
+ PP.Diag(Tok.getLocation(), diag::err_pp_missing_lparen) << II->getName();
+ return false;
+ }
+
+ // Save '(' location for possible missing ')' message.
+ SourceLocation LParenLoc = Tok.getLocation();
+
+ // Get the module name.
+ PP.LexNonComment(Tok);
+
+ // Ensure that we have an identifier.
+ if (Tok.isNot(tok::identifier)) {
+ PP.Diag(Tok.getLocation(), diag::err_expected_id_building_module);
+ return false;
+ }
+
+ bool Result
+ = Tok.getIdentifierInfo()->getName() == PP.getLangOpts().CurrentModule;
+
+ // Get ')'.
+ PP.LexNonComment(Tok);
+
+ // Ensure we have a trailing ).
+ if (Tok.isNot(tok::r_paren)) {
+ PP.Diag(Tok.getLocation(), diag::err_pp_missing_rparen) << II->getName();
+ PP.Diag(LParenLoc, diag::note_matching) << "(";
+ return false;
+ }
+
+ return Result;
+}
+
/// ExpandBuiltinMacro - If an identifier token is read that is to be expanded
/// as a builtin macro, handle it and return the next token as 'Tok'.
void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
@@ -1162,6 +1217,18 @@
OS << (int)Value;
Tok.setKind(tok::numeric_constant);
+ } else if (II == Ident__building_module) {
+ // The argument to this builtin should be an identifier. The
+ // builtin evaluates to 1 when that identifier names the module we are
+ // currently building.
+ OS << (int)EvaluateBuildingModule(Tok, II, *this);
+ Tok.setKind(tok::numeric_constant);
+ } else if (II == Ident__MODULE__) {
+ // The current module as an identifier.
+ OS << getLangOpts().CurrentModule;
+ IdentifierInfo *ModuleII = getIdentifierInfo(getLangOpts().CurrentModule);
+ Tok.setIdentifierInfo(ModuleII);
+ Tok.setKind(ModuleII->getTokenID());
} else {
llvm_unreachable("Unknown identifier!");
}