[WebAssembly] Use 64-bit table when targeting wasm64

See WebAssembly/memory64#51

Author: sbc100

lld/test/wasm/shared64.s

@@ -154,6 +154,7 @@ get_local_func_address:
 # CHECK-NEXT:           Index:           0
 # CHECK-NEXT:           ElemType:        FUNCREF
 # CHECK-NEXT:           Limits:
+# CHECK-NEXT:             Flags:         [ IS_64 ]
 # CHECK-NEXT:             Minimum:         0x2
 # CHECK-NEXT:       - Module:          env
 # CHECK-NEXT:         Field:           __stack_pointer

lld/wasm/Writer.cpp

@@ -939,6 +939,8 @@ static void finalizeIndirectFunctionTable() {
     limits.Flags |= WASM_LIMITS_FLAG_HAS_MAX;
     limits.Maximum = limits.Minimum;
   }
+  if (config->is64.value_or(false))
+    limits.Flags |= WASM_LIMITS_FLAG_IS_64;
   WasmSym::indirectFunctionTable->setLimits(limits);
 }
 

llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp

@@ -885,18 +885,6 @@ bool WebAssemblyFastISel::selectCall(const Instruction *I) {
       Table->setNoStrip();
       MIB.addImm(0);
     }
-    // See if we must truncate the function pointer.
-    // CALL_INDIRECT takes an i32, but in wasm64 we represent function pointers
-    // as 64-bit for uniformity with other pointer types.
-    // See also: WebAssemblyISelLowering.cpp: LowerCallResults
-    if (Subtarget->hasAddr64()) {
-      auto Wrap = BuildMI(*FuncInfo.MBB, std::prev(FuncInfo.InsertPt), MIMD,
-                          TII.get(WebAssembly::I32_WRAP_I64));
-      Register Reg32 = createResultReg(&WebAssembly::I32RegClass);
-      Wrap.addReg(Reg32, RegState::Define);
-      Wrap.addReg(CalleeReg);
-      CalleeReg = Reg32;
-    }
   }
 
   for (unsigned ArgReg : Args)