The Tor Browser: js/src/jit/arm/BaselineHelpers-arm.h@129ffea94266 (annotated)

js/src/jit/arm/BaselineHelpers-arm.h@129ffea94266 (annotated)

js/src/jit/arm/BaselineHelpers-arm.h

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * vim: set ts=8 sts=4 et sw=4 tw=99:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef jit_arm_BaselineHelpers_arm_h
 #define jit_arm_BaselineHelpers_arm_h
 #ifdef JS_ION
 #include "jit/BaselineFrame.h"
 #include "jit/BaselineIC.h"
 #include "jit/BaselineRegisters.h"
 #include "jit/IonMacroAssembler.h"
 namespace js {
 namespace jit {
 // Distance from sp to the top Value inside an IC stub (no return address on the stack on ARM).
 static const size_t ICStackValueOffset = 0;
 inline void
 EmitRestoreTailCallReg(MacroAssembler &masm)
 {
     // No-op on ARM because link register is always holding the return address.
 }
 inline void
 EmitRepushTailCallReg(MacroAssembler &masm)
 {
     // No-op on ARM because link register is always holding the return address.
 }
 inline void
 EmitCallIC(CodeOffsetLabel *patchOffset, MacroAssembler &masm)
 {
     // Move ICEntry offset into BaselineStubReg
     CodeOffsetLabel offset = masm.movWithPatch(ImmWord(-1), BaselineStubReg);
     *patchOffset = offset;
     // Load stub pointer into BaselineStubReg
     masm.loadPtr(Address(BaselineStubReg, ICEntry::offsetOfFirstStub()), BaselineStubReg);
     // Load stubcode pointer from BaselineStubEntry.
     // R2 won't be active when we call ICs, so we can use r0.
     JS_ASSERT(R2 == ValueOperand(r1, r0));
     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);
     // Call the stubcode via a direct branch-and-link
     masm.ma_blx(r0);
 }
 inline void
 EmitEnterTypeMonitorIC(MacroAssembler &masm,
                        size_t monitorStubOffset = ICMonitoredStub::offsetOfFirstMonitorStub())
 {
     // This is expected to be called from within an IC, when BaselineStubReg
     // is properly initialized to point to the stub.
     masm.loadPtr(Address(BaselineStubReg, (uint32_t) monitorStubOffset), BaselineStubReg);
     // Load stubcode pointer from BaselineStubEntry.
     // R2 won't be active when we call ICs, so we can use r0.
     JS_ASSERT(R2 == ValueOperand(r1, r0));
     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);
     // Jump to the stubcode.
     masm.branch(r0);
 }
 inline void
 EmitReturnFromIC(MacroAssembler &masm)
 {
     masm.ma_mov(lr, pc);
 }
 inline void
 EmitChangeICReturnAddress(MacroAssembler &masm, Register reg)
 {
     masm.ma_mov(reg, lr);
 }
 inline void
 EmitTailCallVM(JitCode *target, MacroAssembler &masm, uint32_t argSize)
 {
     // We assume during this that R0 and R1 have been pushed, and that R2 is
     // unused.
     JS_ASSERT(R2 == ValueOperand(r1, r0));
     // Compute frame size.
     masm.movePtr(BaselineFrameReg, r0);
     masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), r0);
     masm.ma_sub(BaselineStackReg, r0);
     // Store frame size without VMFunction arguments for GC marking.
     masm.ma_sub(r0, Imm32(argSize), r1);
     masm.store32(r1, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
     // Push frame descriptor and perform the tail call.
     // BaselineTailCallReg (lr) already contains the return address (as we keep it there through
     // the stub calls), but the VMWrapper code being called expects the return address to also
     // be pushed on the stack.
     JS_ASSERT(BaselineTailCallReg == lr);
     masm.makeFrameDescriptor(r0, JitFrame_BaselineJS);
     masm.push(r0);
     masm.push(lr);
     masm.branch(target);
 }
 inline void
 EmitCreateStubFrameDescriptor(MacroAssembler &masm, Register reg)
 {
     // Compute stub frame size. We have to add two pointers: the stub reg and previous
     // frame pointer pushed by EmitEnterStubFrame.
     masm.mov(BaselineFrameReg, reg);
     masm.ma_add(Imm32(sizeof(void *) * 2), reg);
     masm.ma_sub(BaselineStackReg, reg);
     masm.makeFrameDescriptor(reg, JitFrame_BaselineStub);
 }
 inline void
 EmitCallVM(JitCode *target, MacroAssembler &masm)
 {
     EmitCreateStubFrameDescriptor(masm, r0);
     masm.push(r0);
     masm.call(target);
 }
 // Size of vales pushed by EmitEnterStubFrame.
 static const uint32_t STUB_FRAME_SIZE = 4 * sizeof(void *);
 static const uint32_t STUB_FRAME_SAVED_STUB_OFFSET = sizeof(void *);
 inline void
 EmitEnterStubFrame(MacroAssembler &masm, Register scratch)
 {
     JS_ASSERT(scratch != BaselineTailCallReg);
     // Compute frame size.
     masm.mov(BaselineFrameReg, scratch);
     masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), scratch);
     masm.ma_sub(BaselineStackReg, scratch);
     masm.store32(scratch, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
     // Note: when making changes here,  don't forget to update STUB_FRAME_SIZE
     // if needed.
     // Push frame descriptor and return address.
     masm.makeFrameDescriptor(scratch, JitFrame_BaselineJS);
     masm.push(scratch);
     masm.push(BaselineTailCallReg);
     // Save old frame pointer, stack pointer and stub reg.
     masm.push(BaselineStubReg);
     masm.push(BaselineFrameReg);
     masm.mov(BaselineStackReg, BaselineFrameReg);
     // We pushed 4 words, so the stack is still aligned to 8 bytes.
     masm.checkStackAlignment();
 }
 inline void
 EmitLeaveStubFrameHead(MacroAssembler &masm, bool calledIntoIon = false)
 {
     // Ion frames do not save and restore the frame pointer. If we called
     // into Ion, we have to restore the stack pointer from the frame descriptor.
     // If we performed a VM call, the descriptor has been popped already so
     // in that case we use the frame pointer.
     if (calledIntoIon) {
         masm.pop(ScratchRegister);
         masm.ma_lsr(Imm32(FRAMESIZE_SHIFT), ScratchRegister, ScratchRegister);
         masm.ma_add(ScratchRegister, BaselineStackReg);
     } else {
         masm.mov(BaselineFrameReg, BaselineStackReg);
     }
 }
 inline void
 EmitLeaveStubFrameCommonTail(MacroAssembler &masm)
 {
     masm.pop(BaselineFrameReg);
     masm.pop(BaselineStubReg);
     // Load the return address.
     masm.pop(BaselineTailCallReg);
     // Discard the frame descriptor.
     masm.pop(ScratchRegister);
 }
 inline void
 EmitLeaveStubFrame(MacroAssembler &masm, bool calledIntoIon = false)
 {
     EmitLeaveStubFrameHead(masm, calledIntoIon);
     EmitLeaveStubFrameCommonTail(masm);
 }
 inline void
 EmitStowICValues(MacroAssembler &masm, int values)
 {
     JS_ASSERT(values >= 0 && values <= 2);
     switch(values) {
       case 1:
         // Stow R0
         masm.pushValue(R0);
         break;
       case 2:
         // Stow R0 and R1
         masm.pushValue(R0);
         masm.pushValue(R1);
         break;
     }
 }
 inline void
 EmitUnstowICValues(MacroAssembler &masm, int values, bool discard = false)
 {
     JS_ASSERT(values >= 0 && values <= 2);
     switch(values) {
       case 1:
         // Unstow R0
         if (discard)
             masm.addPtr(Imm32(sizeof(Value)), BaselineStackReg);
         else
             masm.popValue(R0);
         break;
       case 2:
         // Unstow R0 and R1
         if (discard) {
             masm.addPtr(Imm32(sizeof(Value) * 2), BaselineStackReg);
         } else {
             masm.popValue(R1);
             masm.popValue(R0);
         }
         break;
     }
 }
 inline void
 EmitCallTypeUpdateIC(MacroAssembler &masm, JitCode *code, uint32_t objectOffset)
 {
     JS_ASSERT(R2 == ValueOperand(r1, r0));
     // R0 contains the value that needs to be typechecked.
     // The object we're updating is a boxed Value on the stack, at offset
     // objectOffset from esp, excluding the return address.
     // Save the current BaselineStubReg to stack, as well as the TailCallReg,
     // since on ARM, the LR is live.
     masm.push(BaselineStubReg);
     masm.push(BaselineTailCallReg);
     // This is expected to be called from within an IC, when BaselineStubReg
     // is properly initialized to point to the stub.
     masm.loadPtr(Address(BaselineStubReg, ICUpdatedStub::offsetOfFirstUpdateStub()),
                  BaselineStubReg);
     // TODO: Change r0 uses below to use masm's configurable scratch register instead.
     // Load stubcode pointer from BaselineStubReg into BaselineTailCallReg.
     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);
     // Call the stubcode.
     masm.ma_blx(r0);
     // Restore the old stub reg and tailcall reg.
     masm.pop(BaselineTailCallReg);
     masm.pop(BaselineStubReg);
     // The update IC will store 0 or 1 in R1.scratchReg() reflecting if the
     // value in R0 type-checked properly or not.
     Label success;
     masm.cmp32(R1.scratchReg(), Imm32(1));
     masm.j(Assembler::Equal, &success);
     // If the IC failed, then call the update fallback function.
     EmitEnterStubFrame(masm, R1.scratchReg());
     masm.loadValue(Address(BaselineStackReg, STUB_FRAME_SIZE + objectOffset), R1);
     masm.pushValue(R0);
     masm.pushValue(R1);
     masm.push(BaselineStubReg);
     // Load previous frame pointer, push BaselineFrame *.
     masm.loadPtr(Address(BaselineFrameReg, 0), R0.scratchReg());
     masm.pushBaselineFramePtr(R0.scratchReg(), R0.scratchReg());
     EmitCallVM(code, masm);
     EmitLeaveStubFrame(masm);
     // Success at end.
     masm.bind(&success);
 }
 template <typename AddrType>
 inline void
 EmitPreBarrier(MacroAssembler &masm, const AddrType &addr, MIRType type)
 {
     // on ARM, lr is clobbered by patchableCallPreBarrier.  Save it first.
     masm.push(lr);
     masm.patchableCallPreBarrier(addr, type);
     masm.pop(lr);
 }
 inline void
 EmitStubGuardFailure(MacroAssembler &masm)
 {
     JS_ASSERT(R2 == ValueOperand(r1, r0));
     // NOTE: This routine assumes that the stub guard code left the stack in the
     // same state it was in when it was entered.
     // BaselineStubEntry points to the current stub.
     // Load next stub into BaselineStubReg
     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfNext()), BaselineStubReg);
     // Load stubcode pointer from BaselineStubEntry into scratch register.
     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);
     // Return address is already loaded, just jump to the next stubcode.
     JS_ASSERT(BaselineTailCallReg == lr);
     masm.branch(r0);
 }
 } // namespace jit
 } // namespace js
 #endif // JS_ION
 #endif /* jit_arm_BaselineHelpers_arm_h */

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js/src/jit/arm/BaselineHelpers-arm.h@129ffea94266 (annotated)

js/src/jit/arm/BaselineHelpers-arm.h