[mips] [IAS] Fix using .cpsetup with local labels (PR22518).

[tomatabacu]

Summary

Parse for an MCExpr instead of an Identifier and use the symbol for relocations, not just the symbol's name.

This fixes errors when using local labels in .cpsetup (PR22518).

[tomatabacu]

Keep in mind that I'm still looking for a way to use .text+offset for the relocation, instead of hanging on to the $tmp0 symbol.

[seanbruno]

Functional commentary, not code. This does appear to allow freebsd to build farther and avoid failures related to its use of .cpsetup.

[dsanders]

LGTM with a whitespace nit.

test/MC/Mips/cpsetup.s

109

Nit: Two blank lines

[tomatabacu]

Addressed the whitespace nit.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

if (!SaveOpnd.isGPRAsmReg()) {
       return false;
     }
     Save = SaveOpnd.getGPR32Reg();
   }
 
   if (!eatComma("unexpected token, expected comma"))
     return true;
 
-  StringRef Name;
-  if (Parser.parseIdentifier(Name))
-    reportParseError("expected identifier");
-  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+  const MCExpr *Expr;
+  if (Parser.parseExpression(Expr)) {
+    reportParseError("expected expression");
+    return false;
+  }
+
+  if (Expr->getKind() != MCExpr::SymbolRef) {
+    reportParseError("expected symbol");
+    return false;
+  }
+  const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr *>(Expr);
 
-  getTargetStreamer().emitDirectiveCpsetup(FuncReg, Save, *Sym, SaveIsReg);
+  getTargetStreamer().emitDirectiveCpsetup(FuncReg, Save, Ref->getSymbol(),
+                                           SaveIsReg);
   return false;
 }
 
 bool MipsAsmParser::parseDirectiveNaN() {
   MCAsmParser &Parser = getParser();
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     const AsmToken &Tok = Parser.getTok();
 

lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp

if (IsReg) {
     Inst.addOperand(MCOperand::CreateReg(Mips::GP));
     Inst.addOperand(MCOperand::CreateReg(Mips::SP));
     Inst.addOperand(MCOperand::CreateImm(RegOrOffset));
   }
   getStreamer().EmitInstruction(Inst, STI);
   Inst.clear();
 
   const MCSymbolRefExpr *HiExpr = MCSymbolRefExpr::Create(
-      Sym.getName(), MCSymbolRefExpr::VK_Mips_GPOFF_HI, MCA.getContext());
+      &Sym, MCSymbolRefExpr::VK_Mips_GPOFF_HI, MCA.getContext());
   const MCSymbolRefExpr *LoExpr = MCSymbolRefExpr::Create(
-      Sym.getName(), MCSymbolRefExpr::VK_Mips_GPOFF_LO, MCA.getContext());
+      &Sym, MCSymbolRefExpr::VK_Mips_GPOFF_LO, MCA.getContext());
+
   // lui $gp, %hi(%neg(%gp_rel(funcSym)))
   Inst.setOpcode(Mips::LUi);
   Inst.addOperand(MCOperand::CreateReg(Mips::GP));
   Inst.addOperand(MCOperand::CreateExpr(HiExpr));
   getStreamer().EmitInstruction(Inst, STI);
   Inst.clear();
 
   // addiu  $gp, $gp, %lo(%neg(%gp_rel(funcSym)))

test/MC/Mips/cpsetup-bad.s

 # RUN: not llvm-mc %s -triple mips64-unknown-unknown 2>%t1
 # RUN:   FileCheck %s < %t1 -check-prefix=ASM
 
         .text
         .option pic2
 t1:
         .cpsetup $bar, 8, __cerror
 # ASM: :[[@LINE-1]]:18: error: expected register containing function address
         .cpsetup $33, 8, __cerror
 # ASM: :[[@LINE-1]]:18: error: invalid register
         .cpsetup $31, foo, __cerror
 # ASM: :[[@LINE-1]]:23: error: expected save register or stack offset
         .cpsetup $31, $32, __cerror
 # ASM: :[[@LINE-1]]:23: error: invalid register
+        .cpsetup $25, $2, $3
+# ASM: :[[@LINE-1]]:28: error: expected expression
+        .cpsetup $25, $2, 4
+# ASM: :[[@LINE-1]]:28: error: expected symbol
+        .cpsetup $25, $2, 4+65
+# ASM: :[[@LINE-1]]:31: error: expected symbol
+        .cpsetup $25, $2, foo+4
+# ASM: :[[@LINE-1]]:32: error: expected symbol

test/MC/Mips/cpsetup.s

 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi o32 -filetype=obj -o - %s | \
 # RUN:   llvm-objdump -d -r -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=O32 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi o32 %s | \
 # RUN:   FileCheck -check-prefix=ASM %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi n32 -filetype=obj -o - %s | \
-# RUN:   llvm-objdump -d -r -arch=mips64 - | \
+# RUN:   llvm-objdump -d -r -t -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=NXX -check-prefix=N32 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown -target-abi n32 %s | \
 # RUN:   FileCheck -check-prefix=ASM %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown %s -filetype=obj -o - | \
-# RUN:   llvm-objdump -d -r -arch=mips64 - | \
+# RUN:   llvm-objdump -d -r -t -arch=mips64 - | \
 # RUN:     FileCheck -check-prefix=NXX -check-prefix=N64 %s
 
 # RUN: llvm-mc -triple mips64-unknown-unknown %s | \
 # RUN:   FileCheck -check-prefix=ASM %s
 
         .text
         .option pic2
 t1:

 # NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16  __cerror
 # NXX: addiu    $gp, $gp, 0
 # NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  __cerror
 # N32: addu     $gp, $gp, $25
 # N64: daddu    $gp, $gp, $25
 
 # ASM: .cpsetup $25, $2, __cerror
 
+# .cpsetup with local labels (PR22518):
+1:
+        .cpsetup $25, $2, 1b
+        nop
+        sub $3, $3, $2
+        nop
+
+# O32: t2:
+# O32:   nop
+# O32:   sub $3, $3, $2
+# O32:   nop
+
+# FIXME: Direct object emission for N32 is still under development.
+# N32 doesn't allow 3 operations to be specified in the same relocation
+# record like N64 does.
+
+# NXX: move     $2, $gp
+# NXX: lui      $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16  $tmp0
+# NXX: addiu    $gp, $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  $tmp0
+# N32: addu     $gp, $gp, $25
+# N64: daddu    $gp, $gp, $25
+# NXX: nop
+# NXX: sub $3, $3, $2
+# NXX: nop
+
+# ASM: .cpsetup $25, $2, $tmp0
+
 t3:
         .option pic0
         nop
         .cpsetup $25, 8, __cerror
         nop
 
 # Testing that .cpsetup expands to nothing in this case
 # by checking that the next instruction after the first
 # nop is also a 'nop'.
 # NXX: nop
 # NXX-NEXT: nop
 
 # ASM: nop
 # ASM: .cpsetup $25, 8, __cerror
 # ASM: nop
+
+# For .cpsetup with local labels, we need to check if $tmp0 is in the symbol
+# table:
+# NXX: .text  00000000 $tmp0