[Sparc] Support relocatable expressions in the assembler

[dcederman]

Summary

Allow assembler expressions to start with an identifier. This allows for expressions such as

b symbol + 4

and

mov symEnd - symStart, %g1

The patch builds upon https://reviews.llvm.org/D47136.

[joerg]

The test case needs to be resorted, so that the DOTEXPR test comes last, but otherwise this change works for me.

[dcederman]

Moved DOTEXPR tests to end of file
Changed objdump offsets from dec to hex

llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp

case AsmToken::Percent:
     }
     break;
 
   case AsmToken::Plus:
   case AsmToken::Minus:
   case AsmToken::Integer:
   case AsmToken::LParen:
   case AsmToken::Dot:
-    if (!getParser().parseExpression(EVal, E))
-      Op = SparcOperand::CreateImm(EVal, S, E);
+  case AsmToken::Identifier:
+    if (getParser().parseExpression(EVal, E))
       break;
 
-  case AsmToken::Identifier: {
-    StringRef Identifier;
-    if (!getParser().parseIdentifier(Identifier)) {
-      E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
-      MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
-
-      const MCExpr *Res = MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None,
-                                                  getContext());
+    int64_t Res;
+    if (!EVal->evaluateAsAbsolute(Res)) {
       SparcMCExpr::VariantKind Kind = SparcMCExpr::VK_Sparc_13;
 
       if (getContext().getObjectFileInfo()->isPositionIndependent()) {
         if (isCall)
           Kind = SparcMCExpr::VK_Sparc_WPLT30;
         else
           Kind = SparcMCExpr::VK_Sparc_GOT13;
       }
-
-      Res = SparcMCExpr::create(Kind, Res, getContext());
-
-      Op = SparcOperand::CreateImm(Res, S, E);
+      EVal = SparcMCExpr::create(Kind, EVal, getContext());
     }
+    Op = SparcOperand::CreateImm(EVal, S, E);
     break;
   }
-  }
   return (Op) ? MatchOperand_Success : MatchOperand_ParseFail;
 }
 
 OperandMatchResultTy
 SparcAsmParser::parseBranchModifiers(OperandVector &Operands) {
   // parse (,a|,pn|,pt)+
 
   while (getLexer().is(AsmToken::Comma)) {

llvm/test/MC/Sparc/sparc-assembly-exprs.s

 ! RUN: llvm-mc %s -arch=sparc   -show-encoding | FileCheck %s
+! RUN: llvm-mc %s -arch=sparc -filetype=obj | llvm-objdump -r -d - | FileCheck %s --check-prefix=OBJDUMP
 
         ! CHECK: mov 1033, %o1  ! encoding: [0x92,0x10,0x24,0x09]
         mov      (0x400|9), %o1
         ! CHECK: mov 60, %o2    ! encoding: [0x94,0x10,0x20,0x3c]
         mov      ((12+3)<<2), %o2
 
+        ! CHECK:   ba      symStart+4           ! encoding: [0x10,0b10AAAAAA,A,A]
+        ! CHECK:   fixup A - offset: 0, value: symStart+4, kind: fixup_sparc_br22
+        ! OBJDUMP: ba    1
+symStart:
+        b        symStart + 4
+
+        ! CHECK:   mov     symEnd-symStart, %g1 ! encoding: [0x82,0x10,0b001AAAAA,A]
+        ! CHECK:   fixup A - offset: 0, value: symEnd-symStart, kind: fixup_sparc_13
+        ! OBJDUMP: mov     24, %g1
+        mov      symEnd - symStart, %g1
+
+        ! CHECK:   sethi %hi(sym+10), %g2       ! encoding: [0x05,0b00AAAAAA,A,A]
+        ! CHECK:   fixup A - offset: 0, value: %hi(sym+10), kind: fixup_sparc_hi22
+        ! OBJDUMP: R_SPARC_HI22 sym+0xa
+        sethi    %hi(sym + 10), %g2
+
+        ! CHECK:   call foo+40                  ! encoding: [0b01AAAAAA,A,A,A]
+        ! CHECK:   fixup A - offset: 0, value: foo+40, kind: fixup_sparc_call30
+        ! OBJDUMP: R_SPARC_WDISP30 foo+0x28
+        call     foo + 40
+
+        ! CHECK:   add %g1, val+100, %g1        ! encoding: [0x82,0x00,0b011AAAAA,A]
+        ! CHECK:   fixup A - offset: 0, value: val+100, kind: fixup_sparc_13
+        ! OBJDUMP: R_SPARC_13 val+0x64
+        add      %g1, val + 100, %g1
+
+        ! CHECK:   add %g1, 100+val, %g2        ! encoding: [0x84,0x00,0b011AAAAA,A]
+        ! CHECK:   fixup A - offset: 0, value: 100+val, kind: fixup_sparc_13
+        ! OBJDUMP: R_SPARC_13 val+0x64
+        add      %g1, 100 + val, %g2
+symEnd:
+
 ! "." is exactly like a temporary symbol equated to the current line.
 ! RUN: llvm-mc %s -arch=sparc | FileCheck %s --check-prefix=DOTEXPR
 
         ! DOTEXPR: .Ltmp0
         ! DOTEXPR-NEXT: ba .Ltmp0+8
         b . + 8