[WIP][WebAssembly] custom ISel for tglobaladdr with nonzero offset

[dschuff]

Abandoning in favor of D107940

llvm/lib/MC/WasmObjectWriter.cpp

struct WasmRelocationEntry {
   int64_t Addend;                    // A value to add to the symbol.
   unsigned Type;                     // The type of the relocation.
   const MCSectionWasm *FixupSection; // The section the relocation is targeting.
 
   WasmRelocationEntry(uint64_t Offset, const MCSymbolWasm *Symbol,
                       int64_t Addend, unsigned Type,
                       const MCSectionWasm *FixupSection)
       : Offset(Offset), Symbol(Symbol), Addend(Addend), Type(Type),
-        FixupSection(FixupSection) {}
+        FixupSection(FixupSection) {
+    assert((Addend == 0 || wasm::relocTypeHasAddend(Type)) &&
+           "Reloc entry has addend but its type does not");
+  }
 
   bool hasAddend() const { return wasm::relocTypeHasAddend(Type); }
 
   void print(raw_ostream &Out) const {
     Out << wasm::relocTypetoString(Type) << " Off=" << Offset
         << ", Sym=" << *Symbol << ", Addend=" << Addend
         << ", FixupSection=" << FixupSection->getName();
   }

llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td

defm CONST_F32 : I<(outs F32:$res), (ins f32imm_op:$imm),
                    [(set F32:$res, fpimm:$imm)],
                    "f32.const\t$res, $imm", "f32.const\t$imm", 0x43>;
 defm CONST_F64 : I<(outs F64:$res), (ins f64imm_op:$imm),
                    (outs), (ins f64imm_op:$imm),
                    [(set F64:$res, fpimm:$imm)],
                    "f64.const\t$res, $imm", "f64.const\t$imm", 0x44>;
 } // isMoveImm = 1, isAsCheapAsAMove = 1, isReMaterializable = 1
 
-def : Pat<(i32 (WebAssemblywrapper tglobaladdr:$addr)),
-          (CONST_I32 tglobaladdr:$addr)>, Requires<[IsNotPIC, HasAddr32]>;
+
+def XFormGlobal : SDNodeXForm<tglobaladdr,
+    [{
+    if (N->getOffset() == 0 || isa<GlobalVariable>(N->getGlobal()))
+      return SDValue(CurDAG->getMachineNode(WebAssembly::CONST_I32, SDLoc(N), N->getValueType(0), SDValue(N, 0)), 0);
+    
+    return SDValue(CurDAG->getMachineNode(WebAssembly::ADD_I32, SDLoc(N), N->getValueType(0),
+      SDValue(CurDAG->getMachineNode(WebAssembly::CONST_I32, SDLoc(N), N->getValueType(0),
+        CurDAG->getTargetGlobalAddress(N->getGlobal(), SDLoc(N),
+          N->getValueType(0), 0, N->getTargetFlags())), 0),
+      SDValue(CurDAG->getMachineNode(WebAssembly::CONST_I32, SDLoc(N), N->getValueType(0),
+        CurDAG->getTargetConstant(N->getOffset(), SDLoc(N), N->getValueType(0))), 0)), 0);
+         
+    }]>;
+
+//def FunctionGlobal : PatLeaf<
+//                   (i32 tglobaladdr),
+//    [{}],//[{ llvm::errs() << "blah "<< isa<GlobalAddressSDNode>(N)<<"\n"; N->dump();return true;}],
+//    XFormGlobal>;
+
+
+//def : Pat<(i32 (WebAssemblywrapper FunctionGlobal:$addr)),
+//          (CONST_I32 tglobaladdr:$addr)>, Requires<[IsNotPIC]>;
+
+
+//def : Pat<(i32 (WebAssemblywrapper tglobaladdr:$addr)),
+//          (CONST_I32 tglobaladdr:$addr)>, Requires<[IsNotPIC, HasAddr32]>;
 def : Pat<(i64 (WebAssemblywrapper tglobaladdr:$addr)),
           (CONST_I64 tglobaladdr:$addr)>, Requires<[IsNotPIC, HasAddr64]>;
+def : Pat<(i32 (WebAssemblywrapper tglobaladdr:$addr)),
+          (XFormGlobal tglobaladdr:$addr)>, Requires<[IsNotPIC]>;
+
 
 def : Pat<(i32 (WebAssemblywrapper tglobaladdr:$addr)),
           (GLOBAL_GET_I32 tglobaladdr:$addr)>, Requires<[IsPIC, HasAddr32]>;
 def : Pat<(i64 (WebAssemblywrapper tglobaladdr:$addr)),
           (GLOBAL_GET_I64 tglobaladdr:$addr)>, Requires<[IsPIC, HasAddr64]>;
 
 def : Pat<(i32 (WebAssemblywrapperPIC tglobaladdr:$addr)),
           (CONST_I32 tglobaladdr:$addr)>, Requires<[IsPIC, HasAddr32]>;