llvm-project/llvm/lib/Analysis/AliasAnalysisSummary.cpp

106 lines
3.6 KiB
C++

#include "AliasAnalysisSummary.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Compiler.h"
namespace llvm {
namespace cflaa {
namespace {
LLVM_CONSTEXPR unsigned AttrEscapedIndex = 0;
LLVM_CONSTEXPR unsigned AttrUnknownIndex = 1;
LLVM_CONSTEXPR unsigned AttrGlobalIndex = 2;
LLVM_CONSTEXPR unsigned AttrCallerIndex = 3;
LLVM_CONSTEXPR unsigned AttrFirstArgIndex = 4;
LLVM_CONSTEXPR unsigned AttrLastArgIndex = NumAliasAttrs;
LLVM_CONSTEXPR unsigned AttrMaxNumArgs = AttrLastArgIndex - AttrFirstArgIndex;
// NOTE: These aren't AliasAttrs because bitsets don't have a constexpr
// ctor for some versions of MSVC that we support. We could maybe refactor,
// but...
using AliasAttr = unsigned;
LLVM_CONSTEXPR AliasAttr AttrNone = 0;
LLVM_CONSTEXPR AliasAttr AttrEscaped = 1 << AttrEscapedIndex;
LLVM_CONSTEXPR AliasAttr AttrUnknown = 1 << AttrUnknownIndex;
LLVM_CONSTEXPR AliasAttr AttrGlobal = 1 << AttrGlobalIndex;
LLVM_CONSTEXPR AliasAttr AttrCaller = 1 << AttrCallerIndex;
LLVM_CONSTEXPR AliasAttr ExternalAttrMask =
AttrEscaped | AttrUnknown | AttrGlobal;
}
AliasAttrs getAttrNone() { return AttrNone; }
AliasAttrs getAttrUnknown() { return AttrUnknown; }
bool hasUnknownAttr(AliasAttrs Attr) { return Attr.test(AttrUnknownIndex); }
AliasAttrs getAttrCaller() { return AttrCaller; }
bool hasCallerAttr(AliasAttrs Attr) { return Attr.test(AttrCaller); }
bool hasUnknownOrCallerAttr(AliasAttrs Attr) {
return Attr.test(AttrUnknownIndex) || Attr.test(AttrCallerIndex);
}
AliasAttrs getAttrEscaped() { return AttrEscaped; }
bool hasEscapedAttr(AliasAttrs Attr) { return Attr.test(AttrEscapedIndex); }
static AliasAttr argNumberToAttr(unsigned ArgNum) {
if (ArgNum >= AttrMaxNumArgs)
return AttrUnknown;
// N.B. MSVC complains if we use `1U` here, since AliasAttr' ctor takes
// an unsigned long long.
return AliasAttr(1ULL << (ArgNum + AttrFirstArgIndex));
}
AliasAttrs getGlobalOrArgAttrFromValue(const Value &Val) {
if (isa<GlobalValue>(Val))
return AttrGlobal;
if (auto *Arg = dyn_cast<Argument>(&Val))
// Only pointer arguments should have the argument attribute,
// because things can't escape through scalars without us seeing a
// cast, and thus, interaction with them doesn't matter.
if (!Arg->hasNoAliasAttr() && Arg->getType()->isPointerTy())
return argNumberToAttr(Arg->getArgNo());
return AttrNone;
}
bool isGlobalOrArgAttr(AliasAttrs Attr) {
return Attr.reset(AttrEscapedIndex)
.reset(AttrUnknownIndex)
.reset(AttrCallerIndex)
.any();
}
AliasAttrs getExternallyVisibleAttrs(AliasAttrs Attr) {
return Attr & AliasAttrs(ExternalAttrMask);
}
Optional<InstantiatedValue> instantiateInterfaceValue(InterfaceValue IValue,
CallSite CS) {
auto Index = IValue.Index;
auto Value = (Index == 0) ? CS.getInstruction() : CS.getArgument(Index - 1);
if (Value->getType()->isPointerTy())
return InstantiatedValue{Value, IValue.DerefLevel};
return None;
}
Optional<InstantiatedRelation>
instantiateExternalRelation(ExternalRelation ERelation, CallSite CS) {
auto From = instantiateInterfaceValue(ERelation.From, CS);
if (!From)
return None;
auto To = instantiateInterfaceValue(ERelation.To, CS);
if (!To)
return None;
return InstantiatedRelation{*From, *To, ERelation.Offset};
}
Optional<InstantiatedAttr> instantiateExternalAttribute(ExternalAttribute EAttr,
CallSite CS) {
auto Value = instantiateInterfaceValue(EAttr.IValue, CS);
if (!Value)
return None;
return InstantiatedAttr{*Value, EAttr.Attr};
}
}
}