Implement -Wfour-char-constants, which is an extension, not an extwarn,
and apparently not part of -Wall
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70329 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp
index faa44b6..398082f 100644
--- a/lib/Lex/LiteralSupport.cpp
+++ b/lib/Lex/LiteralSupport.cpp
@@ -631,19 +631,19 @@
// FIXME: The "Value" is an uint64_t so we can handle char literals of
// upto 64-bits.
- assert(PP.getTargetInfo().getIntWidth() <= 64 &&
- "Assumes sizeof(int) on target is <= 64");
- assert(PP.getTargetInfo().getWCharWidth() <= 64 &&
- "Assumes sizeof(wchar) on target is <= 64");
// FIXME: This extensively assumes that 'char' is 8-bits.
assert(PP.getTargetInfo().getCharWidth() == 8 &&
"Assumes char is 8 bits");
+ assert(PP.getTargetInfo().getIntWidth() <= 64 &&
+ (PP.getTargetInfo().getIntWidth() & 7) == 0 &&
+ "Assumes sizeof(int) on target is <= 64 and a multiple of char");
+ assert(PP.getTargetInfo().getWCharWidth() <= 64 &&
+ "Assumes sizeof(wchar) on target is <= 64");
// This is what we will use for overflow detection
llvm::APInt LitVal(PP.getTargetInfo().getIntWidth(), 0);
- bool isFirstChar = true;
- bool isMultiChar = false;
+ unsigned NumCharsSoFar = 0;
while (begin[0] != '\'') {
uint64_t ResultChar;
if (begin[0] != '\\') // If this is a normal character, consume it.
@@ -653,33 +653,33 @@
// If this is a multi-character constant (e.g. 'abc'), handle it. These are
// implementation defined (C99 6.4.4.4p10).
- if (!isFirstChar) {
- // If this is the second character being processed, do special handling.
- if (!isMultiChar) {
- isMultiChar = true;
-
- // Warn about discarding the top bits for multi-char wide-character
- // constants (L'abcd').
- if (IsWide)
- PP.Diag(Loc, diag::warn_extraneous_wide_char_constant);
- else
- PP.Diag(Loc, diag::ext_multichar_character_literal);
- }
-
+ if (NumCharsSoFar) {
if (IsWide) {
// Emulate GCC's (unintentional?) behavior: L'ab' -> L'b'.
LitVal = 0;
} else {
// Narrow character literals act as though their value is concatenated
- // in this implementation.
- if ((LitVal.shl(8)).lshr(8) != LitVal)
+ // in this implementation, but warn on overflow.
+ if (LitVal.countLeadingZeros() < 8)
PP.Diag(Loc, diag::warn_char_constant_too_large);
LitVal <<= 8;
}
}
LitVal = LitVal + ResultChar;
- isFirstChar = false;
+ ++NumCharsSoFar;
+ }
+
+ // If this is the second character being processed, do special handling.
+ if (NumCharsSoFar > 1) {
+ // Warn about discarding the top bits for multi-char wide-character
+ // constants (L'abcd').
+ if (IsWide)
+ PP.Diag(Loc, diag::warn_extraneous_wide_char_constant);
+ else if (NumCharsSoFar != 4)
+ PP.Diag(Loc, diag::ext_multichar_character_literal);
+ else
+ PP.Diag(Loc, diag::ext_four_char_character_literal);
}
// Transfer the value from APInt to uint64_t
@@ -689,7 +689,7 @@
// if 'char' is signed for this target (C99 6.4.4.4p10). Note that multiple
// character constants are not sign extended in the this implementation:
// '\xFF\xFF' = 65536 and '\x0\xFF' = 255, which matches GCC.
- if (!IsWide && !isMultiChar && (Value & 128) &&
+ if (!IsWide && NumCharsSoFar == 1 && (Value & 128) &&
PP.getTargetInfo().isCharSigned())
Value = (signed char)Value;
}