[MC] Support infix operator !

Disabled for Darwin mode.

Also disabled for ARM which has compatible aliases (implied 'sp' operand
in 'srs*' instructions like 'srsda rust-lang#31!').

Author: MaskRay

llvm/include/llvm/MC/MCExpr.h

@@ -500,6 +500,7 @@ class MCBinaryExpr : public MCExpr {
     Mul,  ///< Multiplication.
     NE,   ///< Inequality comparison.
     Or,   ///< Bitwise or.
+    OrNot, ///< Bitwise or not.
     Shl,  ///< Shift left.
     AShr, ///< Arithmetic shift right.
     LShr, ///< Logical shift right.

llvm/lib/MC/MCExpr.cpp

@@ -145,6 +145,7 @@ void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens) const {
     case MCBinaryExpr::Mul:  OS <<  '*'; break;
     case MCBinaryExpr::NE:   OS << "!="; break;
     case MCBinaryExpr::Or:   OS <<  '|'; break;
+    case MCBinaryExpr::OrNot: OS << '!'; break;
     case MCBinaryExpr::Shl:  OS << "<<"; break;
     case MCBinaryExpr::Sub:  OS <<  '-'; break;
     case MCBinaryExpr::Xor:  OS <<  '^'; break;
@@ -920,6 +921,7 @@ bool MCExpr::evaluateAsRelocatableImpl(MCValue &Res, const MCAssembler *Asm,
     case MCBinaryExpr::Mul:  Result = LHS * RHS; break;
     case MCBinaryExpr::NE:   Result = LHS != RHS; break;
     case MCBinaryExpr::Or:   Result = LHS | RHS; break;
+    case MCBinaryExpr::OrNot: Result = LHS | ~RHS; break;
     case MCBinaryExpr::Shl:  Result = uint64_t(LHS) << uint64_t(RHS); break;
     case MCBinaryExpr::Sub:  Result = LHS - RHS; break;
     case MCBinaryExpr::Xor:  Result = LHS ^ RHS; break;

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -1497,8 +1497,6 @@ static unsigned getDarwinBinOpPrecedence(AsmToken::TokenKind K,
     return 1;
 
   // Low Precedence: |, &, ^
-  //
-  // FIXME: gas seems to support '!' as an infix operator?
   case AsmToken::Pipe:
     Kind = MCBinaryExpr::Or;
     return 2;
@@ -1559,7 +1557,8 @@ static unsigned getDarwinBinOpPrecedence(AsmToken::TokenKind K,
   }
 }
 
-static unsigned getGNUBinOpPrecedence(AsmToken::TokenKind K,
+static unsigned getGNUBinOpPrecedence(const MCAsmInfo &MAI,
+                                      AsmToken::TokenKind K,
                                       MCBinaryExpr::Opcode &Kind,
                                       bool ShouldUseLogicalShr) {
   switch (K) {
@@ -1603,12 +1602,18 @@ static unsigned getGNUBinOpPrecedence(AsmToken::TokenKind K,
     Kind = MCBinaryExpr::Sub;
     return 4;
 
-  // High Intermediate Precedence: |, &, ^
+  // High Intermediate Precedence: |, !, &, ^
   //
-  // FIXME: gas seems to support '!' as an infix operator?
   case AsmToken::Pipe:
     Kind = MCBinaryExpr::Or;
     return 5;
+  case AsmToken::Exclaim:
+    // Hack to support ARM compatible aliases (implied 'sp' operand in 'srs*'
+    // instructions like 'srsda #31!') and not parse ! as an infix operator.
+    if (MAI.getCommentString() == "@")
+      return 0;
+    Kind = MCBinaryExpr::OrNot;
+    return 5;
   case AsmToken::Caret:
     Kind = MCBinaryExpr::Xor;
     return 5;
@@ -1639,7 +1644,7 @@ unsigned AsmParser::getBinOpPrecedence(AsmToken::TokenKind K,
                                        MCBinaryExpr::Opcode &Kind) {
   bool ShouldUseLogicalShr = MAI.shouldUseLogicalShr();
   return IsDarwin ? getDarwinBinOpPrecedence(K, Kind, ShouldUseLogicalShr)
-                  : getGNUBinOpPrecedence(K, Kind, ShouldUseLogicalShr);
+                  : getGNUBinOpPrecedence(MAI, K, Kind, ShouldUseLogicalShr);
 }
 
 /// Parse all binary operators with precedence >= 'Precedence'.

llvm/lib/MC/MCParser/MasmParser.cpp

@@ -1720,8 +1720,6 @@ static unsigned getGNUBinOpPrecedence(AsmToken::TokenKind K,
     return 4;
 
   // High Intermediate Precedence: |, &, ^
-  //
-  // FIXME: gas seems to support '!' as an infix operator?
   case AsmToken::Pipe:
     Kind = MCBinaryExpr::Or;
     return 5;

llvm/test/MC/AsmParser/exprs-gnu.s

@@ -0,0 +1,4 @@
+# RUN: llvm-mc -triple=x86_64 %s | FileCheck %s
+
+# CHECK: movl %eax, 15
+movl %eax, 3 ! ~12