From da593c99dc01b393ab082baadce0e6de34df49ac Mon Sep 17 00:00:00 2001
From: Frits van Bommel <fvbommel@wxs.nl>
Date: Sat, 30 May 2009 13:04:49 +0200
Subject: [PATCH] Remove code duplication for vtable loads and improve
 instruction naming to make bitcode with virtual calls easier to read.

---
 gen/classes.cpp | 10 ++++++++--
 gen/classes.h   |  2 +-
 gen/toir.cpp    | 20 +++-----------------
 3 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/gen/classes.cpp b/gen/classes.cpp
index 2ac7be9f..ec20de4d 100644
--- a/gen/classes.cpp
+++ b/gen/classes.cpp
@@ -514,7 +514,7 @@ LLValue* DtoIndexClass(LLValue* src, ClassDeclaration* cd, VarDeclaration* vd)
 
 //////////////////////////////////////////////////////////////////////////////////////////
 
-LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl)
+LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl, char* name)
 {
     // sanity checks
     assert(fdecl->isVirtual());
@@ -533,7 +533,9 @@ LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl)
     // load vtbl ptr
     funcval = DtoLoad(funcval);
     // index vtbl
-    funcval = DtoGEPi(funcval, 0, fdecl->vtblIndex, fdecl->toChars());
+    std::string vtblname = name;
+    vtblname.append("@vtbl");
+    funcval = DtoGEPi(funcval, 0, fdecl->vtblIndex, vtblname.c_str());
     // load funcptr
     funcval = DtoAlignedLoad(funcval);
 
@@ -542,6 +544,10 @@ LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl)
 
     // cast to final funcptr type
     funcval = DtoBitCast(funcval, getPtrToType(DtoType(fdecl->type)));
+
+    // postpone naming until after casting to get the name in call instructions
+    funcval->setName(name);
+
     if (Logger::enabled())
         Logger::cout() << "funcval casted: " << *funcval << '\n';
 
diff --git a/gen/classes.h b/gen/classes.h
index 558fe9f5..4c65084f 100644
--- a/gen/classes.h
+++ b/gen/classes.h
@@ -32,6 +32,6 @@ DValue* DtoDynamicCastInterface(DValue* val, Type* to);
 
 LLValue* DtoIndexClass(LLValue* src, ClassDeclaration* sd, VarDeclaration* vd);
 
-LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl);
+LLValue* DtoVirtualFunctionPointer(DValue* inst, FuncDeclaration* fdecl, char* name);
 
 #endif
diff --git a/gen/toir.cpp b/gen/toir.cpp
index 06cdb226..be72c50b 100644
--- a/gen/toir.cpp
+++ b/gen/toir.cpp
@@ -1134,22 +1134,8 @@ DValue* DotVarExp::toElem(IRState* p)
             assert(funcval);
         }
         else {
-            assert(fdecl->vtblIndex > 0);
-            assert(e1type->ty == Tclass);
-
-            LLValue* zero = DtoConstUint(0);
-            size_t vtblidx = fdecl->vtblIndex;
-            if (Logger::enabled())
-                Logger::cout() << "vthis: " << *vthis << '\n';
-            funcval = DtoGEP(vthis, zero, zero);
-            funcval = DtoLoad(funcval);
-            Logger::println("vtblidx = %lu", vtblidx);
-            funcval = DtoGEP(funcval, zero, DtoConstUint(vtblidx), toChars());
-            funcval = DtoLoad(funcval);
-
-            funcval = DtoBitCast(funcval, getPtrToType(DtoType(fdecl->type)));
-            if (Logger::enabled())
-                Logger::cout() << "funcval casted: " << *funcval << '\n';
+            DImValue vthis3(e1type, vthis);
+            funcval = DtoVirtualFunctionPointer(&vthis3, fdecl, toChars());
         }
 
         return new DFuncValue(fdecl, funcval, vthis2);
@@ -2031,7 +2017,7 @@ DValue* DelegateExp::toElem(IRState* p)
 
     LLValue* castfptr;
     if (func->isVirtual() && !func->isFinal())
-        castfptr = DtoVirtualFunctionPointer(u, func);
+        castfptr = DtoVirtualFunctionPointer(u, func, toChars());
     else if (func->isAbstract())
         assert(0 && "TODO delegate to abstract method");
     else if (func->toParent()->isInterfaceDeclaration())