[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, 4 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
index 20c5f3691d2..99ba18c972d 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
@@ -329,6 +329,8 @@ unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
     return ELF::R_MIPS_HIGHER;
   case Mips::fixup_Mips_HIGHEST:
     return ELF::R_MIPS_HIGHEST;
+  case Mips::fixup_Mips_SUB:
+    return ELF::R_MIPS_SUB;
   case Mips::fixup_Mips_GOT_HI16:
     return ELF::R_MIPS_GOT_HI16;
   case Mips::fixup_Mips_GOT_LO16:
@@ -365,6 +367,8 @@ unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx,
     return ELF::R_MICROMIPS_TLS_TPREL_HI16;
   case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
     return ELF::R_MICROMIPS_TLS_TPREL_LO16;
+  case Mips::fixup_MICROMIPS_SUB:
+    return ELF::R_MICROMIPS_SUB;
   }
 
   llvm_unreachable("invalid fixup kind!");