Match MSVC's handling of commas during macro argument expansion
This allows clang to parse the type_traits header in Visual Studio 2012,
which is included widely in practice.
This is a rework of r163022 by João Matos. The original patch broke
preprocessing of gtest headers, which this patch addresses.
Patch by Will Wilson!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184968 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Lex/Token.h b/include/clang/Lex/Token.h
index bcbe9c9..76c62fe 100644
--- a/include/clang/Lex/Token.h
+++ b/include/clang/Lex/Token.h
@@ -77,7 +77,8 @@
NeedsCleaning = 0x08, // Contained an escaped newline or trigraph.
LeadingEmptyMacro = 0x10, // Empty macro exists before this token.
HasUDSuffix = 0x20, // This string or character literal has a ud-suffix.
- HasUCN = 0x40 // This identifier contains a UCN.
+ HasUCN = 0x40, // This identifier contains a UCN.
+ IgnoredComma = 0x80, // This comma is not a macro argument separator (MS).
};
tok::TokenKind getKind() const { return (tok::TokenKind)Kind; }
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 13fdf85..06f14c2 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -458,7 +458,12 @@
}
} else if (Tok.is(tok::l_paren)) {
++NumParens;
- } else if (Tok.is(tok::comma) && NumParens == 0) {
+ } else if (Tok.is(tok::comma) && NumParens == 0 &&
+ !(Tok.getFlags() & Token::IgnoredComma)) {
+ // In Microsoft-compatibility mode, single commas from nested macro
+ // expansions should not be considered as argument separators. We test
+ // for this with the IgnoredComma token flag above.
+
// Comma ends this argument if there are more fixed arguments expected.
// However, if this is a variadic macro, and this is part of the
// variadic part, then the comma is just an argument token.
diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp
index 4251f0e..4f21995 100644
--- a/lib/Lex/TokenLexer.cpp
+++ b/lib/Lex/TokenLexer.cpp
@@ -278,6 +278,14 @@
unsigned NumToks = MacroArgs::getArgLength(ResultArgToks);
ResultToks.append(ResultArgToks, ResultArgToks+NumToks);
+ // In Microsoft-compatibility mode, we follow MSVC's preprocessing
+ // behavior by not considering single commas from nested macro
+ // expansions as argument separators. Set a flag on the token so we can
+ // test for this later when the macro expansion is processed.
+ if (PP.getLangOpts().MicrosoftMode && NumToks == 1 &&
+ ResultToks.back().is(tok::comma))
+ ResultToks.back().setFlag(Token::IgnoredComma);
+
// If the '##' came from expanding an argument, turn it into 'unknown'
// to avoid pasting.
for (unsigned i = FirstResult, e = ResultToks.size(); i != e; ++i) {
diff --git a/test/Preprocessor/microsoft-ext.c b/test/Preprocessor/microsoft-ext.c
index ec10374..b03f677 100644
--- a/test/Preprocessor/microsoft-ext.c
+++ b/test/Preprocessor/microsoft-ext.c
@@ -22,3 +22,15 @@
ACTION_TEMPLATE(InvokeArgument,
HAS_1_TEMPLATE_PARAMS(int, k),
AND_2_VALUE_PARAMS(p0, p1));
+
+// This tests compatibility with behaviour needed for type_traits in VS2012
+// Test based on _VARIADIC_EXPAND_0X macros in xstddef of VS2012
+#define _COMMA ,
+
+#define MAKER(_arg1, _comma, _arg2) \
+ void func(_arg1 _comma _arg2) {}
+#define MAKE_FUNC(_makerP1, _makerP2, _arg1, _comma, _arg2) \
+ _makerP1##_makerP2(_arg1, _comma, _arg2)
+
+MAKE_FUNC(MAK, ER, int a, _COMMA, int b);
+// CHECK: void func(int a , int b) {}
