[mips][ias] Fix all the hacks related to MIPS-specific unary operator…

…s (%hi/%lo/%gp_rel/etc.).

Summary:
They are now lexed as a single token on targets where
MCAsmInfo::HasMipsExpressions is true and then parsed in a similar way to
the '~' operator as part of MCExpr::parseExpression.

As a result:
* expressions and immediates no longer have different parsing rules. The
  difference is now solely down to whether evaluateAsAbsolute() succeeds.
* %hi(%neg(%gp_rel(x))) are no longer parsed as a single operator and
  decomposed into the three MipsMCExpr nodes. They are parsed directly as
  three MipsMCExpr nodes.
  * parseMemOperand no longer needs to eat all the surrounding parenthesis
    to get at the outermost operator to make this work
* %hi(%neg(%gp_rel(x))) and %lo(%neg(%gp_rel(x))) are no longer the only
  3-in-1 relocs that parse for N64. They're still the only combinations that
  are permitted in relocatable expressions though. Fixing that should be a
  later patch.
* We no longer need to list all the tokens that can occur as the first token of
  an expression or immediate.

test/MC/Mips/expr1.s:
    This change also prevents the incorrect lowering of %lo(2*4)+foo to
    %lo(8+foo) which is not an equivalent expression (the difference is
    whether foo is truncated to 16-bit or not) and the test has been
    updated to account for the macro expansion the correct expression requires.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D23110

llvm-svn: 277988

llvm/include/llvm/MC/MCAsmInfo.h

@@ -363,6 +363,10 @@ class MCAsmInfo {
   // X86_64 ELF.
   bool RelaxELFRelocations = true;
 
+  // If true, then the lexer and expression parser will support %neg(),
+  // %hi(), and similar unary operators.
+  bool HasMipsExpressions = false;
+
 public:
   explicit MCAsmInfo();
   virtual ~MCAsmInfo();
@@ -582,6 +586,7 @@ class MCAsmInfo {
 
   bool canRelaxRelocations() const { return RelaxELFRelocations; }
   void setRelaxELFRelocations(bool V) { RelaxELFRelocations = V; }
+  bool hasMipsExpressions() const { return HasMipsExpressions; }
 };
 }
 

llvm/include/llvm/MC/MCParser/MCAsmLexer.h

@@ -55,7 +55,15 @@ class AsmToken {
     Pipe, PipePipe, Caret,
     Amp, AmpAmp, Exclaim, ExclaimEqual, Percent, Hash,
     Less, LessEqual, LessLess, LessGreater,
-    Greater, GreaterEqual, GreaterGreater, At
+    Greater, GreaterEqual, GreaterGreater, At,
+
+    // MIPS unary expression operators such as %neg.
+    PercentCall16, PercentCall_Hi, PercentCall_Lo, PercentDtprel_Hi,
+    PercentDtprel_Lo, PercentGot, PercentGot_Disp, PercentGot_Hi, PercentGot_Lo,
+    PercentGot_Ofst, PercentGot_Page, PercentGottprel, PercentGp_Rel, PercentHi,
+    PercentHigher, PercentHighest, PercentLo, PercentNeg, PercentPcrel_Hi,
+    PercentPcrel_Lo, PercentTlsgd, PercentTlsldm, PercentTprel_Hi,
+    PercentTprel_Lo
   };
 
 private:

llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h

@@ -228,6 +228,12 @@ class MCTargetAsmParser : public MCAsmParserExtension {
   /// Ensure that all previously parsed instructions have been emitted to the
   /// output streamer, if the target does not emit them immediately.
   virtual void flushPendingInstructions(MCStreamer &Out) { }
+
+  virtual const MCExpr *createTargetUnaryExpr(const MCExpr *E,
+                                              AsmToken::TokenKind OperatorToken,
+                                              MCContext &Ctx) {
+    return nullptr;
+  }
 };
 
 } // End llvm namespace

llvm/lib/MC/MCParser/AsmLexer.cpp

@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/MC/MCParser/AsmLexer.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -600,7 +601,46 @@ AsmToken AsmLexer::LexToken() {
       return AsmToken(AsmToken::ExclaimEqual, StringRef(TokStart, 2));
     }
     return AsmToken(AsmToken::Exclaim, StringRef(TokStart, 1));
-  case '%': return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
+  case '%':
+    if (MAI.hasMipsExpressions()) {
+      AsmToken::TokenKind Operator;
+      unsigned OperatorLength;
+
+      std::tie(Operator, OperatorLength) =
+          StringSwitch<std::pair<AsmToken::TokenKind, unsigned>>(
+              StringRef(CurPtr))
+              .StartsWith("call16", {AsmToken::PercentCall16, 7})
+              .StartsWith("call_hi", {AsmToken::PercentCall_Hi, 8})
+              .StartsWith("call_lo", {AsmToken::PercentCall_Lo, 8})
+              .StartsWith("dtprel_hi", {AsmToken::PercentDtprel_Hi, 10})
+              .StartsWith("dtprel_lo", {AsmToken::PercentDtprel_Lo, 10})
+              .StartsWith("got_disp", {AsmToken::PercentGot_Disp, 9})
+              .StartsWith("got_hi", {AsmToken::PercentGot_Hi, 7})
+              .StartsWith("got_lo", {AsmToken::PercentGot_Lo, 7})
+              .StartsWith("got_ofst", {AsmToken::PercentGot_Ofst, 9})
+              .StartsWith("got_page", {AsmToken::PercentGot_Page, 9})
+              .StartsWith("gottprel", {AsmToken::PercentGottprel, 9})
+              .StartsWith("got", {AsmToken::PercentGot, 4})
+              .StartsWith("gp_rel", {AsmToken::PercentGp_Rel, 7})
+              .StartsWith("higher", {AsmToken::PercentHigher, 7})
+              .StartsWith("highest", {AsmToken::PercentHighest, 8})
+              .StartsWith("hi", {AsmToken::PercentHi, 3})
+              .StartsWith("lo", {AsmToken::PercentLo, 3})
+              .StartsWith("neg", {AsmToken::PercentNeg, 4})
+              .StartsWith("pcrel_hi", {AsmToken::PercentPcrel_Hi, 9})
+              .StartsWith("pcrel_lo", {AsmToken::PercentPcrel_Lo, 9})
+              .StartsWith("tlsgd", {AsmToken::PercentTlsgd, 6})
+              .StartsWith("tlsldm", {AsmToken::PercentTlsldm, 7})
+              .StartsWith("tprel_hi", {AsmToken::PercentTprel_Hi, 9})
+              .StartsWith("tprel_lo", {AsmToken::PercentTprel_Lo, 9})
+              .Default({AsmToken::Percent, 1});
+
+      if (Operator != AsmToken::Percent) {
+        CurPtr += OperatorLength - 1;
+        return AsmToken(Operator, StringRef(TokStart, OperatorLength));
+      }
+    }
+    return AsmToken(AsmToken::Percent, StringRef(TokStart, 1));
   case '/':
     IsAtStartOfStatement = OldIsAtStartOfStatement;
     return LexSlash();

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -1064,6 +1064,43 @@ bool AsmParser::parsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
       return true;
     Res = MCUnaryExpr::createNot(Res, getContext());
     return false;
+  // MIPS unary expression operators. The lexer won't generate these tokens if
+  // MCAsmInfo::HasMipsExpressions is false for the target.
+  case AsmToken::PercentCall16:
+  case AsmToken::PercentCall_Hi:
+  case AsmToken::PercentCall_Lo:
+  case AsmToken::PercentDtprel_Hi:
+  case AsmToken::PercentDtprel_Lo:
+  case AsmToken::PercentGot:
+  case AsmToken::PercentGot_Disp:
+  case AsmToken::PercentGot_Hi:
+  case AsmToken::PercentGot_Lo:
+  case AsmToken::PercentGot_Ofst:
+  case AsmToken::PercentGot_Page:
+  case AsmToken::PercentGottprel:
+  case AsmToken::PercentGp_Rel:
+  case AsmToken::PercentHi:
+  case AsmToken::PercentHigher:
+  case AsmToken::PercentHighest:
+  case AsmToken::PercentLo:
+  case AsmToken::PercentNeg:
+  case AsmToken::PercentPcrel_Hi:
+  case AsmToken::PercentPcrel_Lo:
+  case AsmToken::PercentTlsgd:
+  case AsmToken::PercentTlsldm:
+  case AsmToken::PercentTprel_Hi:
+  case AsmToken::PercentTprel_Lo:
+    Lex(); // Eat the operator.
+    if (Lexer.isNot(AsmToken::LParen))
+      return TokError("expected '(' after operator");
+    Lex(); // Eat the operator.
+    if (parseExpression(Res, EndLoc))
+      return true;
+    if (Lexer.isNot(AsmToken::RParen))
+      return TokError("expected ')'");
+    Lex(); // Eat the operator.
+    Res = getTargetParser().createTargetUnaryExpr(Res, FirstTokenKind, Ctx);
+    return !Res;
   }
 }