PPC: JSEntryTrampoline: check for stack space before pushing arguments

src/ppc/builtins-ppc.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_PPC
 
 #include "src/codegen.h"
 #include "src/debug.h"
@@ skipping 809 matching lines @@
     // Leave construct frame.
   }
 
   __ SmiToPtrArrayOffset(r4, r4);
   __ add(sp, sp, r4);
   __ addi(sp, sp, Operand(kPointerSize));
   __ blr();
 }
 
 
+enum IsTagged { kArgcIsSmiTagged, kArgcIsUntaggedInt };
+
+
+// Clobbers r5; preserves all other registers.
+static void Generate_CheckStackOverflow(MacroAssembler* masm,
+                                        const int calleeOffset, Register argc,
+                                        IsTagged argc_is_tagged) {
+  // Check the stack for overflow. We are not trying to catch
+  // interruptions (e.g. debug break and preemption) here, so the "real stack
+  // limit" is checked.
+  Label okay;
+  __ LoadRoot(r5, Heap::kRealStackLimitRootIndex);
+  // Make r5 the space we have left. The stack might already be overflowed
+  // here which will cause r5 to become negative.
+  __ sub(r5, sp, r5);
+  // Check if the arguments will overflow the stack.
+  if (argc_is_tagged == kArgcIsSmiTagged) {
+    __ SmiToPtrArrayOffset(r0, argc);
+  } else {
+    DCHECK(argc_is_tagged == kArgcIsUntaggedInt);
+    __ ShiftLeftImm(r0, argc, Operand(kPointerSizeLog2));
+  }
+  __ cmp(r5, r0);
+  __ bgt(&okay);  // Signed comparison.
+
+  // Out of stack space.
+  __ LoadP(r4, MemOperand(fp, calleeOffset));
+  if (argc_is_tagged == kArgcIsUntaggedInt) {
+    __ SmiTag(argc);
+  }
+  __ Push(r4, argc);
+  __ InvokeBuiltin(Builtins::STACK_OVERFLOW, CALL_FUNCTION);
+
+  __ bind(&okay);
+}
+
+
 static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                              bool is_construct) {
   // Called from Generate_JS_Entry
   // r3: code entry
   // r4: function
   // r5: receiver
   // r6: argc
   // r7: argv
   // r0,r8-r9, cp may be clobbered
   ProfileEntryHookStub::MaybeCallEntryHook(masm);
 
   // Clear the context before we push it when entering the internal frame.
   __ li(cp, Operand::Zero());
 
   // Enter an internal frame.
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
 
     // Set up the context from the function argument.
     __ LoadP(cp, FieldMemOperand(r4, JSFunction::kContextOffset));
 
     __ InitializeRootRegister();
 
     // Push the function and the receiver onto the stack.
     __ push(r4);
     __ push(r5);
 
+    // Check if we have enough stack space to push all arguments.
+    // The function is the first thing that was pushed above after entering
+    // the internal frame.
+    const int kFunctionOffset =
+        InternalFrameConstants::kCodeOffset - kPointerSize;
+    // Clobbers r5.
+    Generate_CheckStackOverflow(masm, kFunctionOffset, r6, kArgcIsUntaggedInt);
+
     // Copy arguments to the stack in a loop.
     // r4: function
     // r6: argc
     // r7: argv, i.e. points to first arg
     Label loop, entry;
     __ ShiftLeftImm(r0, r6, Operand(kPointerSizeLog2));
     __ add(r5, r7, r0);
     // r5 points past last arg.
     __ b(&entry);
     __ bind(&loop);
@@ skipping 492 matching lines @@
   __ cmp(r5, r3);  // Check formal and actual parameter counts.
   __ Jump(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
           RelocInfo::CODE_TARGET, ne);
 
   __ LoadP(ip, FieldMemOperand(r4, JSFunction::kCodeEntryOffset));
   ParameterCount expected(0);
   __ InvokeCode(ip, expected, expected, JUMP_FUNCTION, NullCallWrapper());
 }
 
 
-static void Generate_CheckStackOverflow(MacroAssembler* masm,
-                                        const int calleeOffset) {
-  // Check the stack for overflow. We are not trying to catch
-  // interruptions (e.g. debug break and preemption) here, so the "real stack
-  // limit" is checked.
-  Label okay;
-  __ LoadRoot(r5, Heap::kRealStackLimitRootIndex);
-  // Make r5 the space we have left. The stack might already be overflowed
-  // here which will cause r5 to become negative.
-  __ sub(r5, sp, r5);
-  // Check if the arguments will overflow the stack.
-  __ SmiToPtrArrayOffset(r0, r3);
-  __ cmp(r5, r0);
-  __ bgt(&okay);  // Signed comparison.
-
-  // Out of stack space.
-  __ LoadP(r4, MemOperand(fp, calleeOffset));
-  __ Push(r4, r3);
-  __ InvokeBuiltin(Builtins::STACK_OVERFLOW, CALL_FUNCTION);
-
-  __ bind(&okay);
-}
-
-
 static void Generate_PushAppliedArguments(MacroAssembler* masm,
                                           const int argumentsOffset,
                                           const int indexOffset,
                                           const int limitOffset) {
   Label entry, loop;
   __ LoadP(r3, MemOperand(fp, indexOffset));
   __ b(&entry);
 
   // Load the current argument from the arguments array and push it to the
   // stack.
@@ skipping 37 matching lines @@
     __ LoadP(r3, MemOperand(fp, kFunctionOffset));  // get the function
     __ push(r3);
     __ LoadP(r3, MemOperand(fp, kArgumentsOffset));  // get the args array
     __ push(r3);
     if (targetIsArgument) {
       __ InvokeBuiltin(Builtins::REFLECT_APPLY_PREPARE, CALL_FUNCTION);
     } else {
       __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);
     }
 
-    Generate_CheckStackOverflow(masm, kFunctionOffset);
+    Generate_CheckStackOverflow(masm, kFunctionOffset, r3, kArgcIsSmiTagged);
 
     // Push current limit and index.
     const int kIndexOffset =
         StandardFrameConstants::kExpressionsOffset - (2 * kPointerSize);
     const int kLimitOffset =
         StandardFrameConstants::kExpressionsOffset - (1 * kPointerSize);
     __ li(r4, Operand::Zero());
     __ Push(r3, r4);  // limit and initial index.
 
     // Get the receiver.
@@ skipping 116 matching lines @@
     // Validate arguments
     __ bind(&validate_arguments);
     __ LoadP(r3, MemOperand(fp, kFunctionOffset));  // get the function
     __ push(r3);
     __ LoadP(r3, MemOperand(fp, kArgumentsOffset));  // get the args array
     __ push(r3);
     __ LoadP(r3, MemOperand(fp, kNewTargetOffset));  // get the new.target
     __ push(r3);
     __ InvokeBuiltin(Builtins::REFLECT_CONSTRUCT_PREPARE, CALL_FUNCTION);
 
-    Generate_CheckStackOverflow(masm, kFunctionOffset);
+    Generate_CheckStackOverflow(masm, kFunctionOffset, r3, kArgcIsSmiTagged);
 
     // Push current limit and index.
     const int kIndexOffset =
         StandardFrameConstants::kExpressionsOffset - (2 * kPointerSize);
     const int kLimitOffset =
         StandardFrameConstants::kExpressionsOffset - (1 * kPointerSize);
     __ li(r4, Operand::Zero());
     __ Push(r3, r4);  // limit and initial index.
     // Push newTarget and callee functions
     __ LoadP(r3, MemOperand(fp, kNewTargetOffset));
@@ skipping 205 matching lines @@
     __ bkpt(0);
   }
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_PPC