MIPS/Asm/O32: Don't add another $ to PrivateGlobal symbol

For asm code like:
xx:
	la	$2,$yy
$yy:
	nop

MIPS O32 use `$` as PrivateGlobalPrefix, while another
`$` is added for getOrCreateSymbol, thus:
  error: Undefined temporary symbol $$yy

We also set symbols that starts with `.L` as local for O32.

See: #65020.

Author: wzssyqa

llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

@@ -2920,6 +2920,11 @@ bool MipsAsmParser::loadAndAddSymbolAddress(const MCExpr *SymExpr,
         (Res.getSymA()->getSymbol().isELF() &&
          cast<MCSymbolELF>(Res.getSymA()->getSymbol()).getBinding() ==
              ELF::STB_LOCAL);
+    if (!IsLocalSym && ABI.IsO32()) {
+      // PrivateGlobalPrefix for O32 is '$', while we support '.L' anyway.
+      if (Res.getSymA()->getSymbol().getName().starts_with(".L"))
+        IsLocalSym = true;
+    }
     bool UseXGOT = STI->hasFeature(Mips::FeatureXGOT) && !IsLocalSym;
 
     // The case where the result register is $25 is somewhat special. If the
@@ -6359,7 +6364,7 @@ bool MipsAsmParser::parseOperand(OperandVector &Operands, StringRef Mnemonic) {
       return true;
 
     SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
-    MCSymbol *Sym = getContext().getOrCreateSymbol("$" + Identifier);
+    MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
     // Otherwise create a symbol reference.
     const MCExpr *SymRef =
         MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());

llvm/test/MC/Mips/macro-la-local.s

@@ -0,0 +1,23 @@
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r2 | \
+# RUN:   FileCheck %s --check-prefixes=CHECK
+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 | \
+# RUN:   FileCheck %s --check-prefixes=CHECK
+
+	.text
+	.abicalls
+	.option	pic2
+xx:
+	la	$2,.Lhello #CHECK: lw      $2, %got(.Lhello)($gp)          # encoding: [0x8f,0x82,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %got(.Lhello), kind: fixup_Mips_GOT
+                           #CHECK: addiu   $2, $2, %lo(.Lhello)            # encoding: [0x24,0x42,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %lo(.Lhello), kind: fixup_Mips_LO16
+
+	la	$2,$hello2 #CHECK: lw      $2, %got($hello2)($gp)          # encoding: [0x8f,0x82,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %got($hello2), kind: fixup_Mips_GOT
+                           #CHECK: addiu   $2, $2, %lo($hello2)            # encoding: [0x24,0x42,A,A]
+                           #CHECK: #   fixup A - offset: 0, value: %lo($hello2), kind: fixup_Mips_LO16
+	.rdata
+.Lhello:
+	.asciz "Hello world\n"
+$hello2:
+	.asciz "Hello world\n"