[llvm] [Xtensa] Implement base CallConvention. (PR #83280)

[Sergei Barannikov via llvm-commits]

================
@@ -25,12 +29,193 @@
 
 using namespace llvm;
 
+static MCSymbolRefExpr::VariantKind
+getModifierVariantKind(XtensaCP::XtensaCPModifier Modifier) {
+  switch (Modifier) {
+  case XtensaCP::no_modifier:
+    return MCSymbolRefExpr::VK_None;
+  case XtensaCP::TPOFF:
+    return MCSymbolRefExpr::VK_TPOFF;
+  }
+  report_fatal_error("Invalid XtensaCPModifier!");
+}
+
 void XtensaAsmPrinter::emitInstruction(const MachineInstr *MI) {
   MCInst LoweredMI;
   lowerToMCInst(MI, LoweredMI);
   EmitToStreamer(*OutStreamer, LoweredMI);
 }
 
+void XtensaAsmPrinter::emitMachineConstantPoolValue(
+    MachineConstantPoolValue *MCPV) {
+  XtensaConstantPoolValue *ACPV = static_cast<XtensaConstantPoolValue *>(MCPV);
+  MCSymbol *MCSym;
+
+  assert(ACPV->isExtSymbol() && "unrecognized constant pool value");
+
+  XtensaConstantPoolSymbol *XtensaSym = cast<XtensaConstantPoolSymbol>(ACPV);
+  const char *Sym = XtensaSym->getSymbol();
+  std::string SymName(Sym);
+  if (XtensaSym->isPrivateLinkage())
+    SymName = ".L" + SymName;
+  MCSym = GetExternalSymbolSymbol(StringRef(SymName));
+
+  MCSymbol *LblSym = GetCPISymbol(ACPV->getLabelId());
+  // TODO find a better way to check whether we emit data to .s file
+  if (OutStreamer->hasRawTextSupport()) {
+    SmallString<60> Str;
+    raw_svector_ostream LiteralStr(Str);
+    LiteralStr << "\t.literal " << LblSym->getName() << ", "
+               << MCSym->getName();
+
+    StringRef Modifier = ACPV->getModifierText();
+    LiteralStr << Modifier;
+
+    OutStreamer->emitRawText(StringRef(LiteralStr.str()));
+  } else {
+    MCSymbolRefExpr::VariantKind VK =
+        getModifierVariantKind(ACPV->getModifier());
+
+    if (ACPV->getModifier() != XtensaCP::no_modifier) {
+      std::string SymName(MCSym->getName());
+      MCSym = GetExternalSymbolSymbol(StringRef(SymName));
+    }
+
+    const MCExpr *Expr = MCSymbolRefExpr::create(MCSym, VK, OutContext);
+    uint64_t Size = getDataLayout().getTypeAllocSize(ACPV->getType());
+    OutStreamer->emitCodeAlignment(
+        Align(4), OutStreamer->getContext().getSubtargetInfo());
+    OutStreamer->emitLabel(LblSym);
+    OutStreamer->emitValue(Expr, Size);
+  }
+}
+
+void XtensaAsmPrinter::emitMachineConstantPoolEntry(
+    const MachineConstantPoolEntry &CPE, int i) {
+  if (CPE.isMachineConstantPoolEntry()) {
+    XtensaConstantPoolValue *ACPV =
+        static_cast<XtensaConstantPoolValue *>(CPE.Val.MachineCPVal);
+    ACPV->setLabelId(i);
+    emitMachineConstantPoolValue(CPE.Val.MachineCPVal);
+  } else {
+    MCSymbol *LblSym = GetCPISymbol(i);
+    // TODO find a better way to check whether we emit data to .s file
+    if (OutStreamer->hasRawTextSupport()) {
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s-barannikov wrote:

Same as above, should use `XtensaTargetStreamer::emitLiteral` or add a more appropriate method if necessary to avoid if/else.


https://github.com/llvm/llvm-project/pull/83280