PPC/s390: [wasm] Implement patching of far jump table

Port 0a8ddb13

Original Commit Message:

    If the jump is too large for a near jump, we patch the far jump table
    instead, and patch the (near) jump table to jump to the far jump table
    slot.

R=clemensh@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ic42dfea83799ba6aae1d6d32607391393353815a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1802742Reviewed-by: Milad Farazmand <miladfar@ca.ibm.com>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#63769}

src/wasm/jump-table-assembler.cc

@@ -198,15 +198,21 @@ void JumpTableAssembler::EmitLazyCompileJumpSlot(uint32_t func_index,
   b(r1);  // 2 bytes
 }
 
-void JumpTableAssembler::EmitJumpSlot(Address target) {
+bool JumpTableAssembler::EmitJumpSlot(Address target) {
   mov(r1, Operand(target));
   b(r1);
+  return true;
 }
 
 void JumpTableAssembler::EmitFarJumpSlot(Address target) {
   JumpToInstructionStream(target);
 }
 
+// static
+void JumpTableAssembler::PatchFarJumpSlot(Address slot, Address target) {
+  UNREACHABLE();
+}
+
 void JumpTableAssembler::NopBytes(int bytes) {
   DCHECK_LE(0, bytes);
   DCHECK_EQ(0, bytes % 2);
@@ -259,16 +265,22 @@ void JumpTableAssembler::EmitLazyCompileJumpSlot(uint32_t func_index,
   for (int i = 0; i < nop_bytes; i += kInstrSize) nop();
 }
 
-void JumpTableAssembler::EmitJumpSlot(Address target) {
+bool JumpTableAssembler::EmitJumpSlot(Address target) {
   mov(r0, Operand(target));
   mtctr(r0);
   bctr();
+  return true;
 }
 
 void JumpTableAssembler::EmitFarJumpSlot(Address target) {
   JumpToInstructionStream(target);
 }
 
+// static
+void JumpTableAssembler::PatchFarJumpSlot(Address slot, Address target) {
+  UNREACHABLE();
+}
+
 void JumpTableAssembler::NopBytes(int bytes) {
   DCHECK_LE(0, bytes);
   DCHECK_EQ(0, bytes % 4);