Reland "[Liftoff] Rename kConstant to kI32Const"

This is a reland of f22156bf.

Original change's description:
> [Liftoff] Rename kConstant to kI32Const
>
> This makes it more clear that we only store i32 values as constants in
> the cache state.
>
> R=ahaas@chromium.org
>
> Bug: v8:6600
> Change-Id: I3022e963e864c9c533cbb673bd8502481389799b
> Reviewed-on: https://chromium-review.googlesource.com/853870
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50437}

Bug: v8:6600
Change-Id: I4c28f379eab525a0c86866c39b2e6b55f7c5ab1a
Reviewed-on: https://chromium-review.googlesource.com/857017
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50446}

src/wasm/baseline/ia32/liftoff-assembler-ia32.h

@@ -411,7 +411,7 @@ void LiftoffAssembler::PushCallerFrameSlot(const VarState& src,
           UNREACHABLE();
       }
       break;
-    case VarState::kConstant:
+    case VarState::kI32Const:
       push(Immediate(src.i32_const()));
       break;
   }

src/wasm/baseline/liftoff-assembler.cc

@@ -127,8 +127,7 @@ class StackTransferRecipe {
           case VarState::kRegister:
             asm_->Spill(dst_index, src.reg());
             break;
-          case VarState::kConstant:
-            // TODO(clemensh): Handle other types than i32.
+          case VarState::kI32Const:
             asm_->Spill(dst_index, WasmValue(src.i32_const()));
             break;
         }
@@ -136,7 +135,7 @@ class StackTransferRecipe {
       case VarState::kRegister:
         LoadIntoRegister(dst.reg(), src, src_index);
         break;
-      case VarState::kConstant:
+      case VarState::kI32Const:
         DCHECK_EQ(dst, src);
         break;
     }
@@ -153,7 +152,7 @@ class StackTransferRecipe {
         DCHECK_EQ(dst.reg_class(), src.reg_class());
         if (dst != src.reg()) MoveRegister(dst, src.reg());
         break;
-      case VarState::kConstant:
+      case VarState::kI32Const:
         LoadConstant(dst, WasmValue(src.i32_const()));
         break;
     }
@@ -309,7 +308,7 @@ LiftoffRegister LiftoffAssembler::PopToRegister(RegClass rc,
       DCHECK_EQ(rc, slot.reg_class());
       cache_state_.dec_used(slot.reg());
       return slot.reg();
-    case VarState::kConstant: {
+    case VarState::kI32Const: {
       LiftoffRegister reg = GetUnusedRegister(rc, pinned);
       LoadConstant(reg, WasmValue(slot.i32_const()));
       return reg;
@@ -356,7 +355,7 @@ void LiftoffAssembler::Spill(uint32_t index) {
       Spill(index, slot.reg());
       cache_state_.dec_used(slot.reg());
       break;
-    case VarState::kConstant:
+    case VarState::kI32Const:
       Spill(index, WasmValue(slot.i32_const()));
       break;
   }
@@ -490,7 +489,7 @@ std::ostream& operator<<(std::ostream& os, VarState slot) {
       return os << "s";
     case VarState::kRegister:
       return os << slot.reg();
-    case VarState::kConstant:
+    case VarState::kI32Const:
       return os << "c" << slot.i32_const();
   }
   UNREACHABLE();

src/wasm/baseline/liftoff-assembler.h

@@ -38,7 +38,7 @@ class LiftoffAssembler : public TurboAssembler {
 
   class VarState {
    public:
-    enum Location : uint8_t { kStack, kRegister, kConstant };
+    enum Location : uint8_t { kStack, kRegister, kI32Const };
 
     explicit VarState(ValueType type) : loc_(kStack), type_(type) {}
     explicit VarState(ValueType type, LiftoffRegister r)
@@ -46,7 +46,7 @@ class LiftoffAssembler : public TurboAssembler {
       DCHECK_EQ(r.reg_class(), reg_class_for(type));
     }
     explicit VarState(ValueType type, uint32_t i32_const)
-        : loc_(kConstant), type_(type), i32_const_(i32_const) {
+        : loc_(kI32Const), type_(type), i32_const_(i32_const) {
       DCHECK(type_ == kWasmI32 || type_ == kWasmI64);
     }
 
@@ -57,7 +57,7 @@ class LiftoffAssembler : public TurboAssembler {
           return true;
         case kRegister:
           return reg_ == other.reg_;
-        case kConstant:
+        case kI32Const:
           return i32_const_ == other.i32_const_;
       }
       UNREACHABLE();
@@ -67,14 +67,14 @@ class LiftoffAssembler : public TurboAssembler {
     bool is_gp_reg() const { return loc_ == kRegister && reg_.is_gp(); }
     bool is_fp_reg() const { return loc_ == kRegister && reg_.is_fp(); }
     bool is_reg() const { return loc_ == kRegister; }
-    bool is_const() const { return loc_ == kConstant; }
+    bool is_const() const { return loc_ == kI32Const; }
 
     ValueType type() const { return type_; }
 
     Location loc() const { return loc_; }
 
     uint32_t i32_const() const {
-      DCHECK_EQ(loc_, kConstant);
+      DCHECK_EQ(loc_, kI32Const);
       return i32_const_;
     }
     Register gp_reg() const { return reg().gp(); }
@@ -95,7 +95,7 @@ class LiftoffAssembler : public TurboAssembler {
 
     union {
       LiftoffRegister reg_;  // used if loc_ == kRegister
-      uint32_t i32_const_;  // used if loc_ == kConstant
+      uint32_t i32_const_;   // used if loc_ == kI32Const
     };
   };
 

src/wasm/baseline/liftoff-compiler.cc

@@ -19,7 +19,7 @@ namespace internal {
 namespace wasm {
 
 constexpr auto kRegister = LiftoffAssembler::VarState::kRegister;
-constexpr auto kConstant = LiftoffAssembler::VarState::kConstant;
+constexpr auto kI32Const = LiftoffAssembler::VarState::kI32Const;
 constexpr auto kStack = LiftoffAssembler::VarState::kStack;
 
 namespace {
@@ -547,7 +547,7 @@ class LiftoffCompiler {
       case kRegister:
         __ PushRegister(slot.type(), slot.reg());
         break;
-      case kConstant:
+      case kI32Const:
         __ cache_state()->stack_state.emplace_back(operand.type,
                                                    slot.i32_const());
         break;
@@ -592,7 +592,7 @@ class LiftoffCompiler {
         target_slot = source_slot;
         if (is_tee) state.inc_used(target_slot.reg());
         break;
-      case kConstant:
+      case kI32Const:
         __ DropStackSlot(&target_slot);
         target_slot = source_slot;
         break;

src/wasm/baseline/x64/liftoff-assembler-x64.h

@@ -397,7 +397,7 @@ void LiftoffAssembler::PushCallerFrameSlot(const VarState& src,
         movsd(Operand(rsp, 0), src.reg().fp());
       }
       break;
-    case VarState::kConstant:
+    case VarState::kI32Const:
       pushq(Immediate(src.i32_const()));
       break;
   }