[WebAssembly] Use TargetIndex operands in DbgValue to track WebAssembly operands locations

Extends DWARF expression language to express locals/globals locations. (via
target-index operands atm) (possible variants are: non-virtual registers
or address spaces)

The WebAssemblyExplicitLocals can replace virtual registers to targertindex
operand type at the time when WebAssembly backend introduces
{get,set,tee}_local instead of corresponding virtual registers.

Reviewed By: aprantl, dschuff

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D52634

1 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 0a0322f235e..739cbaf694f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -241,6 +241,11 @@ static DbgValueLoc getDebugLocValue(const MachineInstr *MI) {
     MachineLocation MLoc(RegOp.getReg(), Op1.isImm());
     return DbgValueLoc(Expr, MLoc);
   }
+  if (MI->getOperand(0).isTargetIndex()) {
+    auto Op = MI->getOperand(0);
+    return DbgValueLoc(Expr,
+                       TargetIndexLocation(Op.getIndex(), Op.getOffset()));
+  }
   if (MI->getOperand(0).isImm())
     return DbgValueLoc(Expr, MI->getOperand(0).getImm());
   if (MI->getOperand(0).isFPImm())
@@ -2241,6 +2246,11 @@ void DwarfDebug::emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
     if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
       return;
     return DwarfExpr.addExpression(std::move(Cursor));
+  } else if (Value.isTargetIndexLocation()) {
+    TargetIndexLocation Loc = Value.getTargetIndexLocation();
+    // TODO TargetIndexLocation is a target-independent. Currently only the WebAssembly-specific
+    // encoding is supported.
+    DwarfExpr.addWasmLocation(Loc.Index, Loc.Offset);
   } else if (Value.isConstantFP()) {
     APInt RawBytes = Value.getConstantFP()->getValueAPF().bitcastToAPInt();
     DwarfExpr.addUnsignedConstant(RawBytes);