[lld] [llvm] [WebAssembly] Use 64-bit table when targeting wasm64 (PR #92042)

[Sam Clegg via llvm-commits]

https://github.com/sbc100 updated https://github.com/llvm/llvm-project/pull/92042

>From d144b7b628223a6252baf448b8d043e497182c5f Mon Sep 17 00:00:00 2001
From: Sam Clegg <sbc at chromium.org>
Date: Mon, 13 May 2024 14:42:34 -0700
Subject: [PATCH] [WebAssembly] Use 64-bit table when targeting wasm64

See https://github.com/WebAssembly/memory64/issues/51
---
 lld/test/wasm/shared64.s                           |  1 +
 lld/wasm/SyntheticSections.cpp                     |  8 +++-----
 lld/wasm/Writer.cpp                                |  2 ++
 .../lib/Target/WebAssembly/WebAssemblyFastISel.cpp | 12 ------------
 .../Target/WebAssembly/WebAssemblyISelLowering.cpp | 14 --------------
 5 files changed, 6 insertions(+), 31 deletions(-)

diff --git a/lld/test/wasm/shared64.s b/lld/test/wasm/shared64.s
index 3401faed8610c..2148d464f4158 100644
--- a/lld/test/wasm/shared64.s
+++ b/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
diff --git a/lld/wasm/SyntheticSections.cpp b/lld/wasm/SyntheticSections.cpp
index 72e255951608e..b359e0fdc856c 100644
--- a/lld/wasm/SyntheticSections.cpp
+++ b/lld/wasm/SyntheticSections.cpp
@@ -584,12 +584,10 @@ void ElemSection::writeBody() {
   initExpr.Extended = false;
   if (ctx.isPic) {
     initExpr.Inst.Opcode = WASM_OPCODE_GLOBAL_GET;
-    initExpr.Inst.Value.Global =
-        (config->is64.value_or(false) ? WasmSym::tableBase32
-                                      : WasmSym::tableBase)
-            ->getGlobalIndex();
+    initExpr.Inst.Value.Global = WasmSym::tableBase->getGlobalIndex();
   } else {
-    initExpr.Inst.Opcode = WASM_OPCODE_I32_CONST;
+    bool is64 = config->is64.value_or(false);
+    initExpr.Inst.Opcode = is64 ? WASM_OPCODE_I64_CONST : WASM_OPCODE_I32_CONST;
     initExpr.Inst.Value.Int32 = config->tableBase;
   }
   writeInitExpr(os, initExpr);
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 55eff995fb8a1..91d1113df6a3c 100644
--- a/lld/wasm/Writer.cpp
+++ b/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);
 }
 
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 1c62290704fe4..26e13948bc9a6 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/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)
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 527bb4c9fbea6..d524539944170 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -576,20 +576,6 @@ LowerCallResults(MachineInstr &CallResults, DebugLoc DL, MachineBasicBlock *BB,
   const MCInstrDesc &MCID = TII.get(CallOp);
   MachineInstrBuilder MIB(MF, MF.CreateMachineInstr(MCID, DL));
 
-  // 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: WebAssemblyFastISel::selectCall
-  if (IsIndirect && MF.getSubtarget<WebAssemblySubtarget>().hasAddr64()) {
-    Register Reg32 =
-        MF.getRegInfo().createVirtualRegister(&WebAssembly::I32RegClass);
-    auto &FnPtr = CallParams.getOperand(0);
-    BuildMI(*BB, CallResults.getIterator(), DL,
-            TII.get(WebAssembly::I32_WRAP_I64), Reg32)
-        .addReg(FnPtr.getReg());
-    FnPtr.setReg(Reg32);
-  }
-
   // Move the function pointer to the end of the arguments for indirect calls
   if (IsIndirect) {
     auto FnPtr = CallParams.getOperand(0);