void SrcRec::emitFallbackJump(CodeBlock& cb, ConditionCode cc /* = -1 */) {
// This is a spurious platform dependency. TODO(2990497)
JIT::prepareForSmash(
cb,
cc == CC_None ? JIT::X64::kJmpLen : JIT::X64::kJmpccLen
);
auto from = cb.frontier();
TCA destAddr = getFallbackTranslation();
auto incoming = cc < 0 ? IncomingBranch::jmpFrom(from)
: IncomingBranch::jccFrom(from);
JIT::emitSmashableJump(cb, destAddr, cc);
// We'll need to know the location of this jump later so we can
// patch it to new translations added to the chain.
m_inProgressTailJumps.push_back(incoming);
}
void SrcRec::emitFallbackJump(TCA from, int cc /* = -1 */) {
TCA destAddr = getFallbackTranslation();
auto incoming = cc < 0 ? IncomingBranch::jmpFrom(from)
: IncomingBranch::jccFrom(from);
auto& a = tx64->getAsmFor(from);
// emit dummy jump to be smashed via patch()
if (cc < 0) {
a.jmp(a.frontier());
} else {
assert(incoming.type() == IncomingBranch::Tag::JCC);
a.jcc((ConditionCode)cc, a.frontier());
}
patch(incoming, destAddr);
// We'll need to know the location of this jump later so we can
// patch it to new translations added to the chain.
m_inProgressTailJumps.push_back(incoming);
}
FPInvOffset SrcRec::nonResumedSPOff() const {
return svcreq::extract_spoff(getFallbackTranslation());
}
void emit_svcreq_stub(Venv& env, const Venv::SvcReqPatch& p) {
auto& frozen = env.text.frozen().code;
TCA stub = nullptr;
switch (p.svcreq.op) {
case Vinstr::bindjmp:
{ auto const& i = p.svcreq.bindjmp_;
assertx(p.jmp && !p.jcc);
stub = svcreq::emit_bindjmp_stub(frozen, env.text.data(),
env.meta, i.spOff, p.jmp,
i.target, i.trflags);
} break;
case Vinstr::bindjcc:
{ auto const& i = p.svcreq.bindjcc_;
assertx(!p.jmp && p.jcc);
stub = svcreq::emit_bindjmp_stub(frozen, env.text.data(),
env.meta, i.spOff, p.jcc,
i.target, i.trflags);
} break;
case Vinstr::bindaddr:
{ auto const& i = p.svcreq.bindaddr_;
assertx(!p.jmp && !p.jcc);
stub = svcreq::emit_bindaddr_stub(frozen, env.text.data(),
env.meta, i.spOff, i.addr.get(),
i.target, TransFlags{});
// The bound pointer may not belong to the data segment, as is the case
// with SSwitchMap (see #10347945)
auto realAddr = env.text.data().contains((TCA)i.addr.get())
? (TCA*)env.text.data().toDestAddress((TCA)i.addr.get())
: (TCA*)i.addr.get();
*realAddr = stub;
} break;
case Vinstr::fallback:
{ auto const& i = p.svcreq.fallback_;
assertx(p.jmp && !p.jcc);
auto const srcrec = tc::findSrcRec(i.target);
always_assert(srcrec);
stub = i.trflags.packed
? svcreq::emit_retranslate_stub(frozen, env.text.data(),
i.spOff, i.target, i.trflags)
: srcrec->getFallbackTranslation();
} break;
case Vinstr::fallbackcc:
{ auto const& i = p.svcreq.fallbackcc_;
assertx(!p.jmp && p.jcc);
auto const srcrec = tc::findSrcRec(i.target);
always_assert(srcrec);
stub = i.trflags.packed
? svcreq::emit_retranslate_stub(frozen, env.text.data(),
i.spOff, i.target, i.trflags)
: srcrec->getFallbackTranslation();
} break;
default: always_assert(false);
}
assertx(stub != nullptr);
// Register any necessary patches by creating fake labels for the stubs.
if (p.jmp) {
env.jmps.push_back({p.jmp, Vlabel { env.addrs.size() }});
env.addrs.push_back(stub);
}
if (p.jcc) {
env.jccs.push_back({p.jcc, Vlabel { env.addrs.size() }});
env.addrs.push_back(stub);
}
}
void emit_svcreq_stub(Venv& env, const Venv::SvcReqPatch& p) {
auto& frozen = env.text.frozen().code;
TCA stub = nullptr;
switch (p.svcreq.op) {
case Vinstr::bindjmp:
{ auto const& i = p.svcreq.bindjmp_;
assertx(p.jmp && !p.jcc);
stub = svcreq::emit_bindjmp_stub(frozen, env.meta, i.spOff, p.jmp,
i.target, i.trflags);
} break;
case Vinstr::bindjcc:
{ auto const& i = p.svcreq.bindjcc_;
assertx(!p.jmp && p.jcc);
stub = svcreq::emit_bindjmp_stub(frozen, env.meta, i.spOff, p.jcc,
i.target, i.trflags);
} break;
case Vinstr::bindaddr:
{ auto const& i = p.svcreq.bindaddr_;
assertx(!p.jmp && !p.jcc);
stub = svcreq::emit_bindaddr_stub(frozen, env.meta, i.spOff, i.addr,
i.target, TransFlags{});
*i.addr = stub;
} break;
case Vinstr::bindjcc1st:
{ auto const& i = p.svcreq.bindjcc1st_;
assertx(p.jmp && p.jcc);
stub = svcreq::emit_bindjcc1st_stub(frozen, env.meta, i.spOff, p.jcc,
i.targets[1], i.targets[0], i.cc);
} break;
case Vinstr::fallback:
{ auto const& i = p.svcreq.fallback_;
assertx(p.jmp && !p.jcc);
auto const srcrec = mcg->tx().getSrcRec(i.target);
stub = i.trflags.packed
? svcreq::emit_retranslate_stub(frozen, i.spOff, i.target, i.trflags)
: srcrec->getFallbackTranslation();
} break;
case Vinstr::fallbackcc:
{ auto const& i = p.svcreq.fallbackcc_;
assertx(!p.jmp && p.jcc);
auto const srcrec = mcg->tx().getSrcRec(i.target);
stub = i.trflags.packed
? svcreq::emit_retranslate_stub(frozen, i.spOff, i.target, i.trflags)
: srcrec->getFallbackTranslation();
} break;
default: always_assert(false);
}
assertx(stub != nullptr);
// Register any necessary patches by creating fake labels for the stubs.
if (p.jmp) {
env.jmps.push_back({p.jmp, Vlabel { env.addrs.size() }});
env.addrs.push_back(stub);
}
if (p.jcc) {
env.jccs.push_back({p.jcc, Vlabel { env.addrs.size() }});
env.addrs.push_back(stub);
}
}
