[CSA] Fix CSArguments::PopAndReturn for SMIs

Assembler::PopAndReturn expects an Integral type so convert argc from a
SMI if necessary.

On 64-bit architectures, convert 64-bit immediate pop values into
32-bit values. This is safe since the conversion checks that nothing
was truncated.

Also change CodeStubArguments unit tests to use PopAndReturn rather
than Return.

Change-Id: I91b47d2e81dc0504d185ad59752d638b1c3135a7
Reviewed-on: https://chromium-review.googlesource.com/867052Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50645}

src/code-stub-assembler.cc

@@ -10468,7 +10468,9 @@ void CodeStubArguments::PopAndReturn(Node* value) {
   } else {
     pop_count = argc_;
   }
-  assembler_->PopAndReturn(pop_count, value);
+
+  assembler_->PopAndReturn(assembler_->ParameterToWord(pop_count, argc_mode_),
+                           value);
 }
 
 Node* CodeStubAssembler::IsFastElementsKind(Node* elements_kind) {

src/compiler/arm64/code-generator-arm64.cc

@@ -2465,7 +2465,6 @@ void CodeGenerator::AssembleReturn(InstructionOperand* pop) {
   }
 
   if (pop->IsImmediate()) {
-    DCHECK_EQ(Constant::kInt32, g.ToConstant(pop).type());
     pop_count += g.ToConstant(pop).ToInt32();
     __ DropArguments(pop_count);
   } else {

src/compiler/mips64/code-generator-mips64.cc

@@ -3662,7 +3662,6 @@ void CodeGenerator::AssembleReturn(InstructionOperand* pop) {
   }
   int pop_count = static_cast<int>(descriptor->StackParameterCount());
   if (pop->IsImmediate()) {
-    DCHECK_EQ(Constant::kInt32, g.ToConstant(pop).type());
     pop_count += g.ToConstant(pop).ToInt32();
   } else {
     Register pop_reg = g.ToRegister(pop);

src/compiler/x64/code-generator-x64.cc

@@ -3080,7 +3080,6 @@ void CodeGenerator::AssembleReturn(InstructionOperand* pop) {
   }
 
   if (pop->IsImmediate()) {
-    DCHECK_EQ(Constant::kInt32, g.ToConstant(pop).type());
     pop_size += g.ToConstant(pop).ToInt32() * kPointerSize;
     CHECK_LT(pop_size, static_cast<size_t>(std::numeric_limits<int>::max()));
     __ Ret(static_cast<int>(pop_size), rcx);

test/cctest/test-code-stub-assembler.cc

@@ -1706,7 +1706,7 @@ TEST(Arguments) {
   CSA_ASSERT(
       &m, m.WordEqual(arguments.AtIndex(2), m.SmiConstant(Smi::FromInt(14))));
 
-  m.Return(arguments.GetReceiver());
+  arguments.PopAndReturn(arguments.GetReceiver());
 
   FunctionTester ft(asm_tester.GenerateCode(), kNumParams);
   Handle<Object> result = ft.Call(isolate->factory()->undefined_value(),
@@ -1740,7 +1740,7 @@ TEST(ArgumentsWithSmiConstantIndices) {
                                            CodeStubAssembler::SMI_PARAMETERS),
                          m.SmiConstant(Smi::FromInt(14))));
 
-  m.Return(arguments.GetReceiver());
+  arguments.PopAndReturn(arguments.GetReceiver());
 
   FunctionTester ft(asm_tester.GenerateCode(), kNumParams);
   Handle<Object> result = ft.Call(isolate->factory()->undefined_value(),
@@ -1793,7 +1793,7 @@ TEST(ArgumentsWithSmiIndices) {
                                            CodeStubAssembler::SMI_PARAMETERS),
                          m.SmiConstant(Smi::FromInt(14))));
 
-  m.Return(arguments.GetReceiver());
+  arguments.PopAndReturn(arguments.GetReceiver());
 
   FunctionTester ft(asm_tester.GenerateCode(), kNumParams);
   Handle<Object> result = ft.Call(isolate->factory()->undefined_value(),
@@ -1821,7 +1821,7 @@ TEST(ArgumentsForEach) {
   arguments.ForEach(
       list, [&m, &sum](Node* arg) { sum.Bind(m.SmiAdd(sum.value(), arg)); });
 
-  m.Return(sum.value());
+  arguments.PopAndReturn(sum.value());
 
   FunctionTester ft(asm_tester.GenerateCode(), kNumParams);
   Handle<Object> result = ft.Call(isolate->factory()->undefined_value(),