The Tor Browser: js/src/jit/arm/BaselineHelpers-arm.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #ifndef jit_arm_BaselineHelpers_arm_h

     8 #define jit_arm_BaselineHelpers_arm_h

    10 #ifdef JS_ION

    11 #include "jit/BaselineFrame.h"

    12 #include "jit/BaselineIC.h"

    13 #include "jit/BaselineRegisters.h"

    14 #include "jit/IonMacroAssembler.h"

    16 namespace js {

    17 namespace jit {

    19 // Distance from sp to the top Value inside an IC stub (no return address on the stack on ARM).

    20 static const size_t ICStackValueOffset = 0;

    22 inline void

    23 EmitRestoreTailCallReg(MacroAssembler &masm)

    24 {

    25     // No-op on ARM because link register is always holding the return address.

    26 }

    28 inline void

    29 EmitRepushTailCallReg(MacroAssembler &masm)

    30 {

    31     // No-op on ARM because link register is always holding the return address.

    32 }

    34 inline void

    35 EmitCallIC(CodeOffsetLabel *patchOffset, MacroAssembler &masm)

    36 {

    37     // Move ICEntry offset into BaselineStubReg

    38     CodeOffsetLabel offset = masm.movWithPatch(ImmWord(-1), BaselineStubReg);

    39     *patchOffset = offset;

    41     // Load stub pointer into BaselineStubReg

    42     masm.loadPtr(Address(BaselineStubReg, ICEntry::offsetOfFirstStub()), BaselineStubReg);

    44     // Load stubcode pointer from BaselineStubEntry.

    45     // R2 won't be active when we call ICs, so we can use r0.

    46     JS_ASSERT(R2 == ValueOperand(r1, r0));

    47     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);

    49     // Call the stubcode via a direct branch-and-link

    50     masm.ma_blx(r0);

    51 }

    53 inline void

    54 EmitEnterTypeMonitorIC(MacroAssembler &masm,

    55                        size_t monitorStubOffset = ICMonitoredStub::offsetOfFirstMonitorStub())

    56 {

    57     // This is expected to be called from within an IC, when BaselineStubReg

    58     // is properly initialized to point to the stub.

    59     masm.loadPtr(Address(BaselineStubReg, (uint32_t) monitorStubOffset), BaselineStubReg);

    61     // Load stubcode pointer from BaselineStubEntry.

    62     // R2 won't be active when we call ICs, so we can use r0.

    63     JS_ASSERT(R2 == ValueOperand(r1, r0));

    64     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);

    66     // Jump to the stubcode.

    67     masm.branch(r0);

    68 }

    70 inline void

    71 EmitReturnFromIC(MacroAssembler &masm)

    72 {

    73     masm.ma_mov(lr, pc);

    74 }

    76 inline void

    77 EmitChangeICReturnAddress(MacroAssembler &masm, Register reg)

    78 {

    79     masm.ma_mov(reg, lr);

    80 }

    82 inline void

    83 EmitTailCallVM(JitCode *target, MacroAssembler &masm, uint32_t argSize)

    84 {

    85     // We assume during this that R0 and R1 have been pushed, and that R2 is

    86     // unused.

    87     JS_ASSERT(R2 == ValueOperand(r1, r0));

    89     // Compute frame size.

    90     masm.movePtr(BaselineFrameReg, r0);

    91     masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), r0);

    92     masm.ma_sub(BaselineStackReg, r0);

    94     // Store frame size without VMFunction arguments for GC marking.

    95     masm.ma_sub(r0, Imm32(argSize), r1);

    96     masm.store32(r1, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));

    98     // Push frame descriptor and perform the tail call.

    99     // BaselineTailCallReg (lr) already contains the return address (as we keep it there through

   100     // the stub calls), but the VMWrapper code being called expects the return address to also

   101     // be pushed on the stack.

   102     JS_ASSERT(BaselineTailCallReg == lr);

   103     masm.makeFrameDescriptor(r0, JitFrame_BaselineJS);

   104     masm.push(r0);

   105     masm.push(lr);

   106     masm.branch(target);

   107 }

   109 inline void

   110 EmitCreateStubFrameDescriptor(MacroAssembler &masm, Register reg)

   111 {

   112     // Compute stub frame size. We have to add two pointers: the stub reg and previous

   113     // frame pointer pushed by EmitEnterStubFrame.

   114     masm.mov(BaselineFrameReg, reg);

   115     masm.ma_add(Imm32(sizeof(void *) * 2), reg);

   116     masm.ma_sub(BaselineStackReg, reg);

   118     masm.makeFrameDescriptor(reg, JitFrame_BaselineStub);

   119 }

   121 inline void

   122 EmitCallVM(JitCode *target, MacroAssembler &masm)

   123 {

   124     EmitCreateStubFrameDescriptor(masm, r0);

   125     masm.push(r0);

   126     masm.call(target);

   127 }

   129 // Size of vales pushed by EmitEnterStubFrame.

   130 static const uint32_t STUB_FRAME_SIZE = 4 * sizeof(void *);

   131 static const uint32_t STUB_FRAME_SAVED_STUB_OFFSET = sizeof(void *);

   133 inline void

   134 EmitEnterStubFrame(MacroAssembler &masm, Register scratch)

   135 {

   136     JS_ASSERT(scratch != BaselineTailCallReg);

   138     // Compute frame size.

   139     masm.mov(BaselineFrameReg, scratch);

   140     masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), scratch);

   141     masm.ma_sub(BaselineStackReg, scratch);

   143     masm.store32(scratch, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));

   145     // Note: when making changes here,  don't forget to update STUB_FRAME_SIZE

   146     // if needed.

   148     // Push frame descriptor and return address.

   149     masm.makeFrameDescriptor(scratch, JitFrame_BaselineJS);

   150     masm.push(scratch);

   151     masm.push(BaselineTailCallReg);

   153     // Save old frame pointer, stack pointer and stub reg.

   154     masm.push(BaselineStubReg);

   155     masm.push(BaselineFrameReg);

   156     masm.mov(BaselineStackReg, BaselineFrameReg);

   158     // We pushed 4 words, so the stack is still aligned to 8 bytes.

   159     masm.checkStackAlignment();

   160 }

   162 inline void

   163 EmitLeaveStubFrameHead(MacroAssembler &masm, bool calledIntoIon = false)

   164 {

   165     // Ion frames do not save and restore the frame pointer. If we called

   166     // into Ion, we have to restore the stack pointer from the frame descriptor.

   167     // If we performed a VM call, the descriptor has been popped already so

   168     // in that case we use the frame pointer.

   169     if (calledIntoIon) {

   170         masm.pop(ScratchRegister);

   171         masm.ma_lsr(Imm32(FRAMESIZE_SHIFT), ScratchRegister, ScratchRegister);

   172         masm.ma_add(ScratchRegister, BaselineStackReg);

   173     } else {

   174         masm.mov(BaselineFrameReg, BaselineStackReg);

   175     }

   176 }

   178 inline void

   179 EmitLeaveStubFrameCommonTail(MacroAssembler &masm)

   180 {

   181     masm.pop(BaselineFrameReg);

   182     masm.pop(BaselineStubReg);

   184     // Load the return address.

   185     masm.pop(BaselineTailCallReg);

   187     // Discard the frame descriptor.

   188     masm.pop(ScratchRegister);

   189 }

   191 inline void

   192 EmitLeaveStubFrame(MacroAssembler &masm, bool calledIntoIon = false)

   193 {

   194     EmitLeaveStubFrameHead(masm, calledIntoIon);

   195     EmitLeaveStubFrameCommonTail(masm);

   196 }

   198 inline void

   199 EmitStowICValues(MacroAssembler &masm, int values)

   200 {

   201     JS_ASSERT(values >= 0 && values <= 2);

   202     switch(values) {

   203       case 1:

   204         // Stow R0

   205         masm.pushValue(R0);

   206         break;

   207       case 2:

   208         // Stow R0 and R1

   209         masm.pushValue(R0);

   210         masm.pushValue(R1);

   211         break;

   212     }

   213 }

   215 inline void

   216 EmitUnstowICValues(MacroAssembler &masm, int values, bool discard = false)

   217 {

   218     JS_ASSERT(values >= 0 && values <= 2);

   219     switch(values) {

   220       case 1:

   221         // Unstow R0

   222         if (discard)

   223             masm.addPtr(Imm32(sizeof(Value)), BaselineStackReg);

   224         else

   225             masm.popValue(R0);

   226         break;

   227       case 2:

   228         // Unstow R0 and R1

   229         if (discard) {

   230             masm.addPtr(Imm32(sizeof(Value) * 2), BaselineStackReg);

   231         } else {

   232             masm.popValue(R1);

   233             masm.popValue(R0);

   234         }

   235         break;

   236     }

   237 }

   239 inline void

   240 EmitCallTypeUpdateIC(MacroAssembler &masm, JitCode *code, uint32_t objectOffset)

   241 {

   242     JS_ASSERT(R2 == ValueOperand(r1, r0));

   244     // R0 contains the value that needs to be typechecked.

   245     // The object we're updating is a boxed Value on the stack, at offset

   246     // objectOffset from esp, excluding the return address.

   248     // Save the current BaselineStubReg to stack, as well as the TailCallReg,

   249     // since on ARM, the LR is live.

   250     masm.push(BaselineStubReg);

   251     masm.push(BaselineTailCallReg);

   253     // This is expected to be called from within an IC, when BaselineStubReg

   254     // is properly initialized to point to the stub.

   255     masm.loadPtr(Address(BaselineStubReg, ICUpdatedStub::offsetOfFirstUpdateStub()),

   256                  BaselineStubReg);

   258     // TODO: Change r0 uses below to use masm's configurable scratch register instead.

   260     // Load stubcode pointer from BaselineStubReg into BaselineTailCallReg.

   261     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);

   263     // Call the stubcode.

   264     masm.ma_blx(r0);

   266     // Restore the old stub reg and tailcall reg.

   267     masm.pop(BaselineTailCallReg);

   268     masm.pop(BaselineStubReg);

   270     // The update IC will store 0 or 1 in R1.scratchReg() reflecting if the

   271     // value in R0 type-checked properly or not.

   272     Label success;

   273     masm.cmp32(R1.scratchReg(), Imm32(1));

   274     masm.j(Assembler::Equal, &success);

   276     // If the IC failed, then call the update fallback function.

   277     EmitEnterStubFrame(masm, R1.scratchReg());

   279     masm.loadValue(Address(BaselineStackReg, STUB_FRAME_SIZE + objectOffset), R1);

   281     masm.pushValue(R0);

   282     masm.pushValue(R1);

   283     masm.push(BaselineStubReg);

   285     // Load previous frame pointer, push BaselineFrame *.

   286     masm.loadPtr(Address(BaselineFrameReg, 0), R0.scratchReg());

   287     masm.pushBaselineFramePtr(R0.scratchReg(), R0.scratchReg());

   289     EmitCallVM(code, masm);

   290     EmitLeaveStubFrame(masm);

   292     // Success at end.

   293     masm.bind(&success);

   294 }

   296 template <typename AddrType>

   297 inline void

   298 EmitPreBarrier(MacroAssembler &masm, const AddrType &addr, MIRType type)

   299 {

   300     // on ARM, lr is clobbered by patchableCallPreBarrier.  Save it first.

   301     masm.push(lr);

   302     masm.patchableCallPreBarrier(addr, type);

   303     masm.pop(lr);

   304 }

   306 inline void

   307 EmitStubGuardFailure(MacroAssembler &masm)

   308 {

   309     JS_ASSERT(R2 == ValueOperand(r1, r0));

   311     // NOTE: This routine assumes that the stub guard code left the stack in the

   312     // same state it was in when it was entered.

   314     // BaselineStubEntry points to the current stub.

   316     // Load next stub into BaselineStubReg

   317     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfNext()), BaselineStubReg);

   319     // Load stubcode pointer from BaselineStubEntry into scratch register.

   320     masm.loadPtr(Address(BaselineStubReg, ICStub::offsetOfStubCode()), r0);

   322     // Return address is already loaded, just jump to the next stubcode.

   323     JS_ASSERT(BaselineTailCallReg == lr);

   324     masm.branch(r0);

   325 }

   328 } // namespace jit

   329 } // namespace js

   331 #endif // JS_ION

   333 #endif /* jit_arm_BaselineHelpers_arm_h */

The Tor Browser / file revision

js/src/jit/arm/BaselineHelpers-arm.h@6474c204b198

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