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[objc-arc] Treat memcpy, memove, memset as just using pointers, not decrementing them. 

This will be tested in the next commit (which required it). The commit
is going to update a bunch of tests at the same time.

llvm-svn: 232350
This commit is contained in:
Michael Gottesman 2015-03-16 07:02:32 +00:00
parent 6779217ec5
commit 7a26d8fa54
1 changed files with 62 additions and 34 deletions
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96
llvm/lib/Transforms/ObjCARC/ARCInstKind.cpp
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@ -168,6 +168,60 @@ ARCInstKind llvm::objcarc::GetFunctionClass(const Function *F) {
return ARCInstKind::CallOrUser;
}
// A whitelist of intrinsics that we know do not use objc pointers or decrement
// ref counts.
static bool isInertIntrinsic(unsigned ID) {
// TODO: Make this into a covered switch.
switch (ID) {
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
case Intrinsic::stacksave:
case Intrinsic::stackrestore:
case Intrinsic::vastart:
case Intrinsic::vacopy:
case Intrinsic::vaend:
case Intrinsic::objectsize:
case Intrinsic::prefetch:
case Intrinsic::stackprotector:
case Intrinsic::eh_return_i32:
case Intrinsic::eh_return_i64:
case Intrinsic::eh_typeid_for:
case Intrinsic::eh_dwarf_cfa:
case Intrinsic::eh_sjlj_lsda:
case Intrinsic::eh_sjlj_functioncontext:
case Intrinsic::init_trampoline:
case Intrinsic::adjust_trampoline:
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
case Intrinsic::invariant_start:
case Intrinsic::invariant_end:
// Don't let dbg info affect our results.
case Intrinsic::dbg_declare:
case Intrinsic::dbg_value:
// Short cut: Some intrinsics obviously don't use ObjC pointers.
return true;
default:
return false;
}
}
// A whitelist of intrinsics that we know do not use objc pointers or decrement
// ref counts.
static bool isUseOnlyIntrinsic(unsigned ID) {
// We are conservative and even though intrinsics are unlikely to touch
// reference counts, we white list them for safety.
//
// TODO: Expand this into a covered switch. There is a lot more here.
switch (ID) {
case Intrinsic::memcpy:
case Intrinsic::memmove:
case Intrinsic::memset:
return true;
default:
return false;
}
}
/// \brief Determine what kind of construct V is.
ARCInstKind llvm::objcarc::GetARCInstKind(const Value *V) {
if (const Instruction *I = dyn_cast<Instruction>(V)) {
@ -180,49 +234,23 @@ ARCInstKind llvm::objcarc::GetARCInstKind(const Value *V) {
switch (I->getOpcode()) {
case Instruction::Call: {
const CallInst *CI = cast<CallInst>(I);
// Check for calls to special functions.
// See if we have a function that we know something about.
if (const Function *F = CI->getCalledFunction()) {
ARCInstKind Class = GetFunctionClass(F);
if (Class != ARCInstKind::CallOrUser)
return Class;
// None of the intrinsic functions do objc_release. For intrinsics, the
// only question is whether or not they may be users.
switch (F->getIntrinsicID()) {
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
case Intrinsic::stacksave:
case Intrinsic::stackrestore:
case Intrinsic::vastart:
case Intrinsic::vacopy:
case Intrinsic::vaend:
case Intrinsic::objectsize:
case Intrinsic::prefetch:
case Intrinsic::stackprotector:
case Intrinsic::eh_return_i32:
case Intrinsic::eh_return_i64:
case Intrinsic::eh_typeid_for:
case Intrinsic::eh_dwarf_cfa:
case Intrinsic::eh_sjlj_lsda:
case Intrinsic::eh_sjlj_functioncontext:
case Intrinsic::init_trampoline:
case Intrinsic::adjust_trampoline:
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
case Intrinsic::invariant_start:
case Intrinsic::invariant_end:
// Don't let dbg info affect our results.
case Intrinsic::dbg_declare:
case Intrinsic::dbg_value:
// Short cut: Some intrinsics obviously don't use ObjC pointers.
unsigned ID = F->getIntrinsicID();
if (isInertIntrinsic(ID))
return ARCInstKind::None;
default:
break;
}
if (isUseOnlyIntrinsic(ID))
return ARCInstKind::User;
}
// Otherwise, be conservative.
return GetCallSiteClass(CI);
}
case Instruction::Invoke:
// Otherwise, be conservative.
return GetCallSiteClass(cast<InvokeInst>(I));
case Instruction::BitCast:
case Instruction::GetElementPtr: