-//===- ObjCARCUtil.h - ObjC ARC Optimization ----------*- mode: c++ -*-----===//
+//===- ObjCARCUtil.cpp - ObjC ARC Optimization ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
#include "ObjCARC.h"
+#include "llvm/IR/Intrinsics.h"
using namespace llvm;
using namespace llvm::objcarc;
return OS << "IC_Call";
case IC_User:
return OS << "IC_User";
+ case IC_IntrinsicUser:
+ return OS << "IC_IntrinsicUser";
case IC_None:
return OS << "IC_None";
}
InstructionClass llvm::objcarc::GetFunctionClass(const Function *F) {
Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
- // No arguments.
+ // No (mandatory) arguments.
if (AI == AE)
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_autoreleasePoolPush", IC_AutoreleasepoolPush)
+ .Case("clang.arc.use", IC_IntrinsicUser)
.Default(IC_CallOrUser);
// One argument.
.Case("objc_retain_autorelease", IC_FusedRetainAutorelease)
.Case("objc_retainAutorelease", IC_FusedRetainAutorelease)
.Case("objc_retainAutoreleaseReturnValue",IC_FusedRetainAutoreleaseRV)
+ .Case("objc_sync_enter", IC_User)
+ .Case("objc_sync_exit", IC_User)
.Default(IC_CallOrUser);
// Argument is i8**
return StringSwitch<InstructionClass>(F->getName())
.Case("objc_moveWeak", IC_MoveWeak)
.Case("objc_copyWeak", IC_CopyWeak)
+ // Ignore annotation calls. This is important to stop the
+ // optimizer from treating annotations as uses which would
+ // make the state of the pointers they are attempting to
+ // elucidate to be incorrect.
+ .Case("llvm.arc.annotation.topdown.bbstart", IC_None)
+ .Case("llvm.arc.annotation.topdown.bbend", IC_None)
+ .Case("llvm.arc.annotation.bottomup.bbstart", IC_None)
+ .Case("llvm.arc.annotation.bottomup.bbend", IC_None)
.Default(IC_CallOrUser);
}
// Anything else.
return IC_CallOrUser;
}
+
+/// \brief Determine what kind of construct V is.
+InstructionClass
+llvm::objcarc::GetInstructionClass(const Value *V) {
+ if (const Instruction *I = dyn_cast<Instruction>(V)) {
+ // Any instruction other than bitcast and gep with a pointer operand have a
+ // use of an objc pointer. Bitcasts, GEPs, Selects, PHIs transfer a pointer
+ // to a subsequent use, rather than using it themselves, in this sense.
+ // As a short cut, several other opcodes are known to have no pointer
+ // operands of interest. And ret is never followed by a release, so it's
+ // not interesting to examine.
+ switch (I->getOpcode()) {
+ case Instruction::Call: {
+ const CallInst *CI = cast<CallInst>(I);
+ // Check for calls to special functions.
+ if (const Function *F = CI->getCalledFunction()) {
+ InstructionClass Class = GetFunctionClass(F);
+ if (Class != IC_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.
+ return IC_None;
+ default:
+ break;
+ }
+ }
+ return GetCallSiteClass(CI);
+ }
+ case Instruction::Invoke:
+ return GetCallSiteClass(cast<InvokeInst>(I));
+ case Instruction::BitCast:
+ case Instruction::GetElementPtr:
+ case Instruction::Select: case Instruction::PHI:
+ case Instruction::Ret: case Instruction::Br:
+ case Instruction::Switch: case Instruction::IndirectBr:
+ case Instruction::Alloca: case Instruction::VAArg:
+ case Instruction::Add: case Instruction::FAdd:
+ case Instruction::Sub: case Instruction::FSub:
+ case Instruction::Mul: case Instruction::FMul:
+ case Instruction::SDiv: case Instruction::UDiv: case Instruction::FDiv:
+ case Instruction::SRem: case Instruction::URem: case Instruction::FRem:
+ case Instruction::Shl: case Instruction::LShr: case Instruction::AShr:
+ case Instruction::And: case Instruction::Or: case Instruction::Xor:
+ case Instruction::SExt: case Instruction::ZExt: case Instruction::Trunc:
+ case Instruction::IntToPtr: case Instruction::FCmp:
+ case Instruction::FPTrunc: case Instruction::FPExt:
+ case Instruction::FPToUI: case Instruction::FPToSI:
+ case Instruction::UIToFP: case Instruction::SIToFP:
+ case Instruction::InsertElement: case Instruction::ExtractElement:
+ case Instruction::ShuffleVector:
+ case Instruction::ExtractValue:
+ break;
+ case Instruction::ICmp:
+ // Comparing a pointer with null, or any other constant, isn't an
+ // interesting use, because we don't care what the pointer points to, or
+ // about the values of any other dynamic reference-counted pointers.
+ if (IsPotentialRetainableObjPtr(I->getOperand(1)))
+ return IC_User;
+ break;
+ default:
+ // For anything else, check all the operands.
+ // Note that this includes both operands of a Store: while the first
+ // operand isn't actually being dereferenced, it is being stored to
+ // memory where we can no longer track who might read it and dereference
+ // it, so we have to consider it potentially used.
+ for (User::const_op_iterator OI = I->op_begin(), OE = I->op_end();
+ OI != OE; ++OI)
+ if (IsPotentialRetainableObjPtr(*OI))
+ return IC_User;
+ }
+ }
+
+ // Otherwise, it's totally inert for ARC purposes.
+ return IC_None;
+}
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