[mips] [IAS] Fix LA with relative label operands.

[tomatabacu]

Summary

Call MCSymbolRefExpr::create() with a MCSymbol* argument, not with a StringRef
of the Symbol's name, in order to avoid creating invalid temporary symbols for
relative labels (e.g. {$,.L}tmp00, {$,.L}tmp10 etc.).

[dsanders]

LGTM with a couple nits.

In the commit message, '$tmp symbol operands' should be 'relative branches'.

Also, I suspect clang-format would format the changes differently. If this is the case could you format it the way clang-format would?

[dsanders]

'relative branches'

Sorry, 'relative labels'

[tomatabacu]

Ran clang-format on changes.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

void MipsAsmParser::expandLoadAddressSym(
   warnIfNoMacro(IDLoc);
 
   if (Is32BitSym && isABI_N64())
     Warning(IDLoc, "instruction loads the 32-bit address of a 64-bit symbol");
 
   MCInst tmpInst;
   unsigned RegNo = DstRegOp.getReg();
   const MCSymbolRefExpr *Symbol = cast<MCSymbolRefExpr>(SymOp.getExpr());
-  const MCSymbolRefExpr *HiExpr =
-      MCSymbolRefExpr::create(Symbol->getSymbol().getName(),
-                              MCSymbolRefExpr::VK_Mips_ABS_HI, getContext());
-  const MCSymbolRefExpr *LoExpr =
-      MCSymbolRefExpr::create(Symbol->getSymbol().getName(),
-                              MCSymbolRefExpr::VK_Mips_ABS_LO, getContext());
+  const MCSymbolRefExpr *HiExpr = MCSymbolRefExpr::create(
+      &Symbol->getSymbol(), MCSymbolRefExpr::VK_Mips_ABS_HI, getContext());
+  const MCSymbolRefExpr *LoExpr = MCSymbolRefExpr::create(
+      &Symbol->getSymbol(), MCSymbolRefExpr::VK_Mips_ABS_LO, getContext());
+
   if (!Is32BitSym) {
     // If it's a 64-bit architecture, expand to:
     // la d,sym => lui  d,highest(sym)
     //             ori  d,d,higher(sym)
     //             dsll d,d,16
     //             ori  d,d,hi16(sym)
     //             dsll d,d,16
     //             ori  d,d,lo16(sym)
-    const MCSymbolRefExpr *HighestExpr =
-        MCSymbolRefExpr::create(Symbol->getSymbol().getName(),
-                                MCSymbolRefExpr::VK_Mips_HIGHEST, getContext());
-    const MCSymbolRefExpr *HigherExpr =
-        MCSymbolRefExpr::create(Symbol->getSymbol().getName(),
-                                MCSymbolRefExpr::VK_Mips_HIGHER, getContext());
+    const MCSymbolRefExpr *HighestExpr = MCSymbolRefExpr::create(
+        &Symbol->getSymbol(), MCSymbolRefExpr::VK_Mips_HIGHEST, getContext());
+    const MCSymbolRefExpr *HigherExpr = MCSymbolRefExpr::create(
+        &Symbol->getSymbol(), MCSymbolRefExpr::VK_Mips_HIGHER, getContext());
 
     tmpInst.setOpcode(Mips::LUi);
     tmpInst.addOperand(MCOperand::createReg(RegNo));
     tmpInst.addOperand(MCOperand::createExpr(HighestExpr));
     Instructions.push_back(tmpInst);
 
     createLShiftOri<0>(MCOperand::createExpr(HigherExpr), RegNo, SMLoc(),
                        Instructions);

test/MC/Mips/mips-expansions.s

 # CHECK: lui     $7, 1               # encoding: [0x01,0x00,0x07,0x3c]
 # CHECK: ori     $7, $7, 2           # encoding: [0x02,0x00,0xe7,0x34]
   la $4, 20($5)
 # CHECK: ori     $4, $5, 20          # encoding: [0x14,0x00,0xa4,0x34]
   la $7, 65538($8)
 # CHECK: lui     $7, 1               # encoding: [0x01,0x00,0x07,0x3c]
 # CHECK: ori     $7, $7, 2           # encoding: [0x02,0x00,0xe7,0x34]
 # CHECK: addu    $7, $7, $8          # encoding: [0x21,0x38,0xe8,0x00]
+  la $8, 1f
+# CHECK: lui     $8, %hi($tmp0)      # encoding: [A,A,0x08,0x3c]
+# CHECK:                             #   fixup A - offset: 0, value: ($tmp0)@ABS_HI, kind: fixup_Mips_HI16
+# CHECK: ori     $8, $8, %lo($tmp0)  # encoding: [A,A,0x08,0x35]
+# CHECK:                             #   fixup A - offset: 0, value: ($tmp0)@ABS_LO, kind: fixup_Mips_LO16
   la $8, symbol
 # CHECK: lui     $8, %hi(symbol)     # encoding: [A,A,0x08,0x3c]
 # CHECK:                             #   fixup A - offset: 0, value: symbol@ABS_HI, kind: fixup_Mips_HI16
 # CHECK: ori     $8, $8, %lo(symbol) # encoding: [A,A,0x08,0x35]
 # CHECK:                             #   fixup A - offset: 0, value: symbol@ABS_LO, kind: fixup_Mips_LO16
 
 # LW/SW and LDC1/SDC1 of symbol address, done by MipsAsmParser::expandMemInst():
   .set noat