[mips][ias] Fix all the hacks related to MIPS-specific unary operators (%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

1 files changed, 41 insertions, 1 deletions

diff --git a/llvm/lib/MC/MCParser/AsmLexer.cpp b/llvm/lib/MC/MCParser/AsmLexer.cpp
index 7037bb1d5fa..be6e84460ea 100644
--- a/llvm/lib/MC/MCParser/AsmLexer.cpp
+++ b/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();