Debugging info: include parameter number for function params.

ctx.cpp

@@ -1482,19 +1482,26 @@ FunctionEmitContext::EmitVariableDebugInfo(Symbol *sym) {
 
 
 void
-FunctionEmitContext::EmitFunctionParameterDebugInfo(Symbol *sym) {
+FunctionEmitContext::EmitFunctionParameterDebugInfo(Symbol *sym, int argNum) {
     if (m->diBuilder == NULL)
         return;
 
     llvm::DIScope scope = diFunction;
+    llvm::DIType diType = sym->type->GetDIType(scope);
+    Assert(diType.Verify());
+    int flags = 0;
+
     llvm::DIVariable var = 
         m->diBuilder->createLocalVariable(llvm::dwarf::DW_TAG_arg_variable,
                                           scope,
                                           sym->name,
                                           sym->pos.GetDIFile(),
                                           sym->pos.first_line,
-                                          sym->type->GetDIType(scope),
-                                          true /* preserve through opts */);
+                                          diType,
+                                          true /* preserve through opts */,
+                                          flags,
+                                          argNum+1);
+    Assert(var.Verify());
     llvm::Instruction *declareInst = 
         m->diBuilder->insertDeclare(sym->storagePtr, var, bblock);
     AddDebugPos(declareInst, &sym->pos, &scope);

ctx.h

@@ -342,7 +342,7 @@ public:
 
     /** Emits debugging information for the function parameter represented
         by sym.  */
-    void EmitFunctionParameterDebugInfo(Symbol *sym);
+    void EmitFunctionParameterDebugInfo(Symbol *sym, int parameterNum);
     /** @} */
 
     /** @name IR instruction emission

func.cpp

@@ -182,7 +182,7 @@ lCopyInTaskParameter(int i, llvm::Value *structArgPtr, const
     // memory
     llvm::Value *ptrval = ctx->LoadInst(ptr, sym->name.c_str());
     ctx->StoreInst(ptrval, sym->storagePtr);
-    ctx->EmitFunctionParameterDebugInfo(sym);
+    ctx->EmitFunctionParameterDebugInfo(sym, i);
 }
 
 
@@ -262,7 +262,7 @@ Function::emitCode(FunctionEmitContext *ctx, llvm::Function *function,
             // to store the its value there.
             sym->storagePtr = ctx->AllocaInst(argIter->getType(), sym->name.c_str());
             ctx->StoreInst(argIter, sym->storagePtr);
-            ctx->EmitFunctionParameterDebugInfo(sym);
+            ctx->EmitFunctionParameterDebugInfo(sym, i);
         }
 
         // If the number of actual function arguments is equal to the