[Liftoff] Fix stack space reservation

LiftoffAssembler::ReserveStackSpace expected number of bytes, not
number of stack slots. Also, make this clear in the naming of the
parameter, and remove a dead field.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: Ic4c7167cfa26a169b2936acdde865863141f441d
Reviewed-on: https://chromium-review.googlesource.com/823967Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50072}

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

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

src/wasm/baseline/arm64/liftoff-assembler-arm64.h

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

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

@@ -31,9 +31,8 @@ inline Operand GetContextOperand() { return Operand(ebp, -16); }
 
 static constexpr DoubleRegister kScratchDoubleReg = xmm7;
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) {
-  stack_space_ = space;
-  sub(esp, Immediate(space));
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {
+  sub(esp, Immediate(bytes));
 }
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {

src/wasm/baseline/liftoff-assembler.h

@@ -243,7 +243,7 @@ class LiftoffAssembler : public TurboAssembler {
   // Platform-specific part.        //
   ////////////////////////////////////
 
-  inline void ReserveStackSpace(uint32_t);
+  inline void ReserveStackSpace(uint32_t bytes);
 
   inline void LoadConstant(LiftoffRegister, WasmValue);
   inline void LoadFromContext(Register dst, uint32_t offset, int size);
@@ -313,7 +313,6 @@ class LiftoffAssembler : public TurboAssembler {
 
  private:
   uint32_t num_locals_ = 0;
-  uint32_t stack_space_ = 0;
   static constexpr uint32_t kInlineLocalTypes = 8;
   union {
     ValueType local_types_[kInlineLocalTypes];

src/wasm/baseline/liftoff-compiler.cc

@@ -165,7 +165,7 @@ class LiftoffCompiler {
     }
     __ EnterFrame(StackFrame::WASM_COMPILED);
     __ set_has_frame(true);
-    __ ReserveStackSpace(__ GetTotalFrameSlotCount());
+    __ ReserveStackSpace(kPointerSize * __ GetTotalFrameSlotCount());
     // Parameter 0 is the wasm context.
     uint32_t num_params =
         static_cast<uint32_t>(call_desc_->ParameterCount()) - 1;

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

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

src/wasm/baseline/mips64/liftoff-assembler-mips64.h

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

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

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

src/wasm/baseline/s390/liftoff-assembler-s390.h

@@ -11,7 +11,7 @@ namespace v8 {
 namespace internal {
 namespace wasm {
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) { USE(stack_space_); }
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {}
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {}
 

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

@@ -29,9 +29,8 @@ inline Operand GetContextOperand() { return Operand(rbp, -16); }
 
 }  // namespace liftoff
 
-void LiftoffAssembler::ReserveStackSpace(uint32_t space) {
-  stack_space_ = space;
-  subp(rsp, Immediate(space));
+void LiftoffAssembler::ReserveStackSpace(uint32_t bytes) {
+  subp(rsp, Immediate(bytes));
 }
 
 void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value) {