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Unified Diff: src/arm/builtins-arm.cc

Issue 1609893003: [es6] Tail calls support. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Rebasing Created 4 years, 11 months ago
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Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index f88324042b0bb4ee14c930213769dc0a0c2ab427..89528566f10d03ae13627490c040cccb00acbbc5 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -1941,10 +1941,126 @@ void Builtins::Generate_Apply(MacroAssembler* masm) {
}
}
+namespace {
+
+// Drops top JavaScript frame and an arguments adaptor frame below it (if
+// present) preserving all the arguments prepared for current call.
+// Does nothing if debugger is currently active.
+// ES6 14.6.3. PrepareForTailCall
+//
+// Stack structure for the function g() tail calling f():
+//
+// ------- Caller frame: -------
+// | ...
+// | g()'s arg M
+// | ...
+// | g()'s arg 1
+// | g()'s receiver arg
+// | g()'s caller pc
+// ------- g()'s frame: -------
+// | g()'s caller fp <- fp
+// | g()'s context
+// | function pointer: g
+// | -------------------------
+// | ...
+// | ...
+// | f()'s arg N
+// | ...
+// | f()'s arg 1
+// | f()'s receiver arg <- sp (f()'s caller pc is not on the stack yet!)
+// ----------------------
+//
+void PrepareForTailCall(MacroAssembler* masm, Register args_reg,
+ Register scratch1, Register scratch2,
+ Register scratch3) {
+ DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
+ Comment cmnt(masm, "[ PrepareForTailCall");
+
+ // Prepare for tail call only if the debugger is not active.
+ Label done;
+ ExternalReference debug_is_active =
+ ExternalReference::debug_is_active_address(masm->isolate());
+ __ mov(scratch1, Operand(debug_is_active));
+ __ ldrb(scratch1, MemOperand(scratch1));
+ __ cmp(scratch1, Operand(0));
+ __ b(ne, &done);
+
+ // Check if next frame is an arguments adaptor frame.
+ Label no_arguments_adaptor, formal_parameter_count_loaded;
+ __ ldr(scratch2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+ __ ldr(scratch3,
+ MemOperand(scratch2, StandardFrameConstants::kContextOffset));
+ __ cmp(scratch3, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
+ __ b(ne, &no_arguments_adaptor);
+
+ // Drop arguments adaptor frame and load arguments count.
+ __ mov(fp, scratch2);
+ __ ldr(scratch1,
+ MemOperand(fp, ArgumentsAdaptorFrameConstants::kLengthOffset));
+ __ SmiUntag(scratch1);
+ __ b(&formal_parameter_count_loaded);
+
+ __ bind(&no_arguments_adaptor);
+ // Load caller's formal parameter count
+ __ ldr(scratch1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
+ __ ldr(scratch1,
+ FieldMemOperand(scratch1, JSFunction::kSharedFunctionInfoOffset));
+ __ ldr(scratch1,
+ FieldMemOperand(scratch1,
+ SharedFunctionInfo::kFormalParameterCountOffset));
+ __ SmiUntag(scratch1);
+
+ __ bind(&formal_parameter_count_loaded);
+
+ // Calculate the end of destination area where we will put the arguments
+ // after we drop current frame. We add kPointerSize to count the receiver
+ // argument which is not included into formal parameters count.
+ Register dst_reg = scratch2;
+ __ add(dst_reg, fp, Operand(scratch1, LSL, kPointerSizeLog2));
+ __ add(dst_reg, dst_reg,
+ Operand(StandardFrameConstants::kCallerSPOffset + kPointerSize));
+
+ Register src_reg = scratch1;
+ __ add(src_reg, sp, Operand(args_reg, LSL, kPointerSizeLog2));
+ // Count receiver argument as well (not included in args_reg).
+ __ add(src_reg, src_reg, Operand(kPointerSize));
+
+ if (FLAG_debug_code) {
+ __ cmp(src_reg, dst_reg);
+ __ Check(lo, kStackAccessBelowStackPointer);
+ }
+
+ // Restore caller's frame pointer and return address now as they will be
+ // overwritten by the copying loop.
+ __ ldr(lr, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
+ __ ldr(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+
+ // Now copy callee arguments to the caller frame going backwards to avoid
+ // callee arguments corruption (source and destination areas could overlap).
+
+ // Both src_reg and dst_reg are pointing to the word after the one to copy,
+ // so they must be pre-decremented in the loop.
+ Register tmp_reg = scratch3;
+ Label loop, entry;
+ __ b(&entry);
+ __ bind(&loop);
+ __ ldr(tmp_reg, MemOperand(src_reg, -kPointerSize, PreIndex));
+ __ str(tmp_reg, MemOperand(dst_reg, -kPointerSize, PreIndex));
+ __ bind(&entry);
+ __ cmp(sp, src_reg);
+ __ b(ne, &loop);
+
+ // Leave current frame.
+ __ mov(sp, dst_reg);
+
+ __ bind(&done);
+}
+} // namespace
// static
void Builtins::Generate_CallFunction(MacroAssembler* masm,
- ConvertReceiverMode mode) {
+ ConvertReceiverMode mode,
+ TailCallMode tail_call_mode) {
// ----------- S t a t e -------------
// -- r0 : the number of arguments (not including the receiver)
// -- r1 : the function to call (checked to be a JSFunction)
@@ -2030,6 +2146,10 @@ void Builtins::Generate_CallFunction(MacroAssembler* masm,
// -- cp : the function context.
// -----------------------------------
+ if (tail_call_mode == TailCallMode::kAllow) {
+ PrepareForTailCall(masm, r0, r3, r4, r5);
+ }
+
__ ldr(r2,
FieldMemOperand(r2, SharedFunctionInfo::kFormalParameterCountOffset));
__ SmiUntag(r2);
@@ -2128,13 +2248,18 @@ void Generate_PushBoundArguments(MacroAssembler* masm) {
// static
-void Builtins::Generate_CallBoundFunction(MacroAssembler* masm) {
+void Builtins::Generate_CallBoundFunctionImpl(MacroAssembler* masm,
+ TailCallMode tail_call_mode) {
// ----------- S t a t e -------------
// -- r0 : the number of arguments (not including the receiver)
// -- r1 : the function to call (checked to be a JSBoundFunction)
// -----------------------------------
__ AssertBoundFunction(r1);
+ if (tail_call_mode == TailCallMode::kAllow) {
+ PrepareForTailCall(masm, r0, r3, r4, r5);
+ }
+
// Patch the receiver to [[BoundThis]].
__ ldr(ip, FieldMemOperand(r1, JSBoundFunction::kBoundThisOffset));
__ str(ip, MemOperand(sp, r0, LSL, kPointerSizeLog2));
@@ -2152,7 +2277,8 @@ void Builtins::Generate_CallBoundFunction(MacroAssembler* masm) {
// static
-void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
+void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode,
+ TailCallMode tail_call_mode) {
// ----------- S t a t e -------------
// -- r0 : the number of arguments (not including the receiver)
// -- r1 : the target to call (can be any Object).
@@ -2162,14 +2288,19 @@ void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
__ JumpIfSmi(r1, &non_callable);
__ bind(&non_smi);
__ CompareObjectType(r1, r4, r5, JS_FUNCTION_TYPE);
- __ Jump(masm->isolate()->builtins()->CallFunction(mode),
+ __ Jump(masm->isolate()->builtins()->CallFunction(mode, tail_call_mode),
RelocInfo::CODE_TARGET, eq);
__ cmp(r5, Operand(JS_BOUND_FUNCTION_TYPE));
- __ Jump(masm->isolate()->builtins()->CallBoundFunction(),
+ __ Jump(masm->isolate()->builtins()->CallBoundFunction(tail_call_mode),
RelocInfo::CODE_TARGET, eq);
__ cmp(r5, Operand(JS_PROXY_TYPE));
__ b(ne, &non_function);
+ // 0. Prepare for tail call if necessary.
+ if (tail_call_mode == TailCallMode::kAllow) {
+ PrepareForTailCall(masm, r0, r3, r4, r5);
+ }
+
// 1. Runtime fallback for Proxy [[Call]].
__ Push(r1);
// Increase the arguments size to include the pushed function and the
@@ -2191,7 +2322,7 @@ void Builtins::Generate_Call(MacroAssembler* masm, ConvertReceiverMode mode) {
// Let the "call_as_function_delegate" take care of the rest.
__ LoadNativeContextSlot(Context::CALL_AS_FUNCTION_DELEGATE_INDEX, r1);
__ Jump(masm->isolate()->builtins()->CallFunction(
- ConvertReceiverMode::kNotNullOrUndefined),
+ ConvertReceiverMode::kNotNullOrUndefined, tail_call_mode),
RelocInfo::CODE_TARGET);
// 3. Call to something that is not callable.
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