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Bug 1387535 part 2 - Encapsulate Label fields better. r=bhackett

This commit is contained in:
Jan de Mooij 2017-08-08 13:55:08 +02:00
Родитель bb851a6aae
Коммит 8239d880f4
7 изменённых файлов: 48 добавлений и 85 удалений
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10
js/src/irregexp/RegExpMacroAssembler.cpp
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@ -156,6 +156,8 @@ InterpretedRegExpMacroAssembler::Backtrack()
Emit(BC_POP_BT, 0);
}
static const int32_t INVALID_OFFSET = -1;
void
InterpretedRegExpMacroAssembler::Bind(jit::Label* label)
{
@ -163,11 +165,12 @@ InterpretedRegExpMacroAssembler::Bind(jit::Label* label)
MOZ_ASSERT(!label->bound());
if (label->used()) {
int pos = label->offset();
while (pos != jit::Label::INVALID_OFFSET) {
MOZ_ASSERT(pos >= 0);
do {
int fixup = pos;
pos = *reinterpret_cast<int32_t*>(buffer_ + fixup);
*reinterpret_cast<uint32_t*>(buffer_ + fixup) = pc_;
}
} while (pos != INVALID_OFFSET);
}
label->bind(pc_);
}
@ -516,7 +519,8 @@ InterpretedRegExpMacroAssembler::EmitOrLink(jit::Label* label)
if (label->bound()) {
Emit32(label->offset());
} else {
int pos = label->use(pc_);
int pos = label->used() ? label->offset() : INVALID_OFFSET;
label->use(pc_);
Emit32(pos);
}
}

19
js/src/jit/Label.h
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@ -14,7 +14,7 @@ namespace jit {
struct LabelBase
{
protected:
private:
// offset_ >= 0 means that the label is either bound or has incoming
// uses and needs to be bound.
int32_t offset_ : 31;
@ -23,11 +23,11 @@ struct LabelBase
// correctly.
uint32_t bound_ : 1;
void operator =(const LabelBase& label) = delete;
void operator=(const LabelBase& label) = delete;
public:
static const int32_t INVALID_OFFSET = -1;
public:
LabelBase() : offset_(INVALID_OFFSET), bound_(false)
{ }
@ -40,13 +40,6 @@ struct LabelBase
MOZ_ASSERT(bound() || used());
return offset_;
}
void offsetBy(int32_t delta) {
MOZ_ASSERT(bound() || used());
MOZ_ASSERT(offset() + delta >= offset(), "no overflow");
mozilla::DebugOnly<int32_t> oldOffset(offset());
offset_ += delta;
MOZ_ASSERT(offset_ == delta + oldOffset, "new offset fits in 31 bits");
}
// Returns whether the label is not bound, but has incoming uses.
bool used() const {
return !bound() && offset_ > INVALID_OFFSET;
@ -65,14 +58,10 @@ struct LabelBase
}
// Sets the label's latest used position, returning the old use position in
// the process.
int32_t use(int32_t offset) {
void use(int32_t offset) {
MOZ_ASSERT(!bound());
int32_t old = offset_;
offset_ = offset;
MOZ_ASSERT(offset_ == offset, "offset fits in 31 bits");
return old;
}
};

27
js/src/jit/arm/Assembler-arm.cpp
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@ -954,8 +954,9 @@ Assembler::processCodeLabels(uint8_t* rawCode)
}
void
Assembler::writeCodePointer(CodeOffset* label) {
BufferOffset off = writeInst(LabelBase::INVALID_OFFSET);
Assembler::writeCodePointer(CodeOffset* label)
{
BufferOffset off = writeInst(-1);
label->bind(off.getOffset());
}
@ -2388,10 +2389,9 @@ Assembler::as_b(Label* l, Condition c)
if (oom())
return BufferOffset();
int32_t old;
BufferOffset ret;
if (l->used()) {
old = l->offset();
int32_t old = l->offset();
// This will currently throw an assertion if we couldn't actually
// encode the offset of the branch.
if (!BOffImm::IsInRange(old)) {
@ -2400,7 +2400,6 @@ Assembler::as_b(Label* l, Condition c)
}
ret = as_b(BOffImm(old), c, l);
} else {
old = LabelBase::INVALID_OFFSET;
BOffImm inv;
ret = as_b(inv, c, l);
}
@ -2408,8 +2407,7 @@ Assembler::as_b(Label* l, Condition c)
if (oom())
return BufferOffset();
DebugOnly<int32_t> check = l->use(ret.getOffset());
MOZ_ASSERT(check == old);
l->use(ret.getOffset());
return ret;
}
@ -2475,20 +2473,18 @@ Assembler::as_bl(Label* l, Condition c)
if (oom())
return BufferOffset();
int32_t old;
BufferOffset ret;
// See if the list was empty :(
// See if the list was empty.
if (l->used()) {
// This will currently throw an assertion if we couldn't actually encode
// the offset of the branch.
old = l->offset();
int32_t old = l->offset();
if (!BOffImm::IsInRange(old)) {
m_buffer.fail_bail();
return ret;
}
ret = as_bl(BOffImm(old), c, l);
} else {
old = LabelBase::INVALID_OFFSET;
BOffImm inv;
ret = as_bl(inv, c, l);
}
@ -2496,8 +2492,7 @@ Assembler::as_bl(Label* l, Condition c)
if (oom())
return BufferOffset();
DebugOnly<int32_t> check = l->use(ret.getOffset());
MOZ_ASSERT(check == old);
l->use(ret.getOffset());
return ret;
}
@ -2924,7 +2919,8 @@ Assembler::retarget(Label* label, Label* target)
// use chain, prepending the entire use chain of target.
Instruction branch = *editSrc(labelBranchOffset);
Condition c = branch.extractCond();
int32_t prev = target->use(label->offset());
int32_t prev = target->offset();
target->use(label->offset());
if (branch.is<InstBImm>())
as_b(BOffImm(prev), c, labelBranchOffset);
else if (branch.is<InstBLImm>())
@ -2934,8 +2930,7 @@ Assembler::retarget(Label* label, Label* target)
} else {
// The target is unbound and unused. We can just take the head of
// the list hanging off of label, and dump that into target.
DebugOnly<uint32_t> prev = target->use(label->offset());
MOZ_ASSERT((int32_t)prev == Label::INVALID_OFFSET);
target->use(label->offset());
}
}
label->reset();

3
js/src/jit/arm64/Assembler-arm64.cpp
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@ -662,8 +662,7 @@ Assembler::retarget(Label* label, Label* target)
} else {
// The target is unbound and unused. We can just take the head of
// the list hanging off of label, and dump that into target.
DebugOnly<uint32_t> prev = target->use(label->offset());
MOZ_ASSERT((int32_t)prev == Label::INVALID_OFFSET);
target->use(label->offset());
}
}
label->reset();

15
js/src/jit/arm64/Assembler-arm64.h
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@ -368,21 +368,8 @@ class Assembler : public vixl::Assembler
static const size_t OffsetOfJumpTableEntryPointer = 8;
public:
void writeCodePointer(AbsoluteLabel* absoluteLabel) {
MOZ_ASSERT(!absoluteLabel->bound());
uintptr_t x = LabelBase::INVALID_OFFSET;
BufferOffset off = EmitData(&x, sizeof(uintptr_t));
// The x86/x64 makes general use of AbsoluteLabel and weaves a linked list
// of uses of an AbsoluteLabel through the assembly. ARM only uses labels
// for the case statements of switch jump tables. Thus, for simplicity, we
// simply treat the AbsoluteLabel as a label and bind it to the offset of
// the jump table entry that needs to be patched.
LabelBase* label = absoluteLabel;
label->bind(off.getOffset());
}
void writeCodePointer(CodeOffset* label) {
uintptr_t x = LabelBase::INVALID_OFFSET;
uintptr_t x = uintptr_t(-1);
BufferOffset off = EmitData(&x, sizeof(uintptr_t));
label->bind(off.getOffset());
}

26
js/src/jit/shared/Assembler-shared.h
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@ -399,32 +399,6 @@ class RepatchLabel
}
};
// An absolute label is like a Label, except it represents an absolute
// reference rather than a relative one. Thus, it cannot be patched until after
// linking.
struct AbsoluteLabel : public LabelBase
{
public:
AbsoluteLabel()
{ }
AbsoluteLabel(const AbsoluteLabel& label) : LabelBase(label)
{ }
int32_t prev() const {
MOZ_ASSERT(!bound());
if (!used())
return INVALID_OFFSET;
return offset();
}
void setPrev(int32_t offset) {
use(offset);
}
void bind() {
bound_ = true;
// These labels cannot be used after being bound.
offset_ = -1;
}
};
class CodeOffset
{

35
js/src/jit/x86-shared/Assembler-x86-shared.h
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@ -449,8 +449,8 @@ class AssemblerX86Shared : public AssemblerShared
masm.nopAlign(alignment);
}
void writeCodePointer(CodeOffset* label) {
// A CodeOffset only has one use, bake in the "end of list" value.
masm.jumpTablePointer(LabelBase::INVALID_OFFSET);
// Use -1 as dummy value. This will be patched after codegen.
masm.jumpTablePointer(-1);
label->bind(masm.size());
}
void cmovz(const Operand& src, Register dest) {
@ -853,7 +853,10 @@ class AssemblerX86Shared : public AssemblerShared
} else {
// Thread the jump list through the unpatched jump targets.
JmpSrc j = masm.jCC(static_cast<X86Encoding::Condition>(cond));
JmpSrc prev = JmpSrc(label->use(j.offset()));
JmpSrc prev;
if (label->used())
prev = JmpSrc(label->offset());
label->use(j.offset());
masm.setNextJump(j, prev);
}
}
@ -864,7 +867,10 @@ class AssemblerX86Shared : public AssemblerShared
} else {
// Thread the jump list through the unpatched jump targets.
JmpSrc j = masm.jmp();
JmpSrc prev = JmpSrc(label->use(j.offset()));
JmpSrc prev;
if (label->used())
prev = JmpSrc(label->offset());
label->use(j.offset());
masm.setNextJump(j, prev);
}
}
@ -877,7 +883,10 @@ class AssemblerX86Shared : public AssemblerShared
masm.linkJump(j, JmpDst(label->offset()));
} else {
// Thread the jump list through the unpatched jump targets.
JmpSrc prev = JmpSrc(label->use(j.offset()));
JmpSrc prev;
if (label->used())
prev = JmpSrc(label->offset());
label->use(j.offset());
masm.setNextJump(j, prev);
}
return j;
@ -992,7 +1001,10 @@ class AssemblerX86Shared : public AssemblerShared
masm.linkJump(jmp, JmpDst(target->offset()));
} else {
// Thread the jump list through the unpatched jump targets.
JmpSrc prev(target->use(jmp.offset()));
JmpSrc prev;
if (target->used())
prev = JmpSrc(target->offset());
target->use(jmp.offset());
masm.setNextJump(jmp, prev);
}
jmp = JmpSrc(next.offset());
@ -1020,11 +1032,14 @@ class AssemblerX86Shared : public AssemblerShared
masm.ret_i(n.value - sizeof(void*));
}
CodeOffset call(Label* label) {
if (label->bound()) {
masm.linkJump(masm.call(), JmpDst(label->offset()));
} else {
JmpSrc j = masm.call();
JmpSrc prev = JmpSrc(label->use(j.offset()));
if (label->bound()) {
masm.linkJump(j, JmpDst(label->offset()));
} else {
JmpSrc prev;
if (label->used())
prev = JmpSrc(label->offset());
label->use(j.offset());
masm.setNextJump(j, prev);
}
return CodeOffset(masm.currentOffset());