llvm-project/clang/lib/Analysis/ThreadSafetyCommon.cpp
Aaron Puchert 73417aa642
Thread Safety Analysis: Compare values of literals (#148551)
The typical case for literals is an array of mutexes, where we want to
distinguish `mutex[0]` from `mutex[1]` and so on. Currently they're
treated as the same expression, in fact all literals are treated as the
same expression.

The infrastructure for literals is already there, although it required
some changes, and some simplifications seemed opportune:
* The `ValueType` had fields for size and signedness. But only integer
have signedness, and the size is irrelevant if we don't want to emit
machine code. For the abstract semantics that we're interested in, only
the number matters.
* We remove the `BT_Void`: `void` literals don't exist in C++.
* We remove `BT_Float` and `BT_ValueRef`: floating-point numbers and
complex numbers are probably not used in lock expressions.
* We replace `BT_Pointer` with `BT_NullPointer`. There are no pointer
literals, only null pointer literals.

It seems to me that `ValueType` was intended to assign types to any node
in the TIL, but it is currently only used for literals. I was trying to
come up with reasons to assign types everywhere, but we're not trying to
type check anything, and we don't support overloading. The comparison of
expressions surely doesn't need it. But maybe this should be clarified
at some point. (Including the fact that it is called Typed Intermediate
Language.)

We turn `Literal` into a pure base class, as it seems to have been
intended, and only create `LiteralT` instances of the correct type.
Assertions on `as` ensure we're not mixing up types.

We print to `llvm::raw_ostream` instead of `std::ostream` because that's
required for `CharacterLiteral::print`.

Fixes https://github.com/llvm/llvm-project/issues/58535.
2026-02-02 20:00:27 +01:00

1101 lines
39 KiB
C++

//===- ThreadSafetyCommon.cpp ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Implementation of the interfaces declared in ThreadSafetyCommon.h
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/Analyses/ThreadSafetyCommon.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclGroup.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/OperationKinds.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/Type.h"
#include "clang/Analysis/Analyses/ThreadSafetyTIL.h"
#include "clang/Analysis/CFG.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/Specifiers.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include <algorithm>
#include <cassert>
#include <string>
#include <utility>
using namespace clang;
using namespace threadSafety;
// From ThreadSafetyUtil.h
std::string threadSafety::getSourceLiteralString(const Expr *CE) {
switch (CE->getStmtClass()) {
case Stmt::IntegerLiteralClass:
return toString(cast<IntegerLiteral>(CE)->getValue(), 10, true);
case Stmt::StringLiteralClass: {
std::string ret("\"");
ret += cast<StringLiteral>(CE)->getString();
ret += "\"";
return ret;
}
case Stmt::CharacterLiteralClass:
case Stmt::CXXNullPtrLiteralExprClass:
case Stmt::GNUNullExprClass:
case Stmt::CXXBoolLiteralExprClass:
case Stmt::FloatingLiteralClass:
case Stmt::ImaginaryLiteralClass:
case Stmt::ObjCStringLiteralClass:
default:
return "#lit";
}
}
// Return true if E is a variable that points to an incomplete Phi node.
static bool isIncompletePhi(const til::SExpr *E) {
if (const auto *Ph = dyn_cast<til::Phi>(E))
return Ph->status() == til::Phi::PH_Incomplete;
return false;
}
static constexpr std::pair<StringRef, bool> ClassifyCapabilityFallback{
/*Kind=*/StringRef("mutex"),
/*Reentrant=*/false};
// Returns pair (Kind, Reentrant).
static std::pair<StringRef, bool> classifyCapability(const TypeDecl &TD) {
if (const auto *CA = TD.getAttr<CapabilityAttr>())
return {CA->getName(), TD.hasAttr<ReentrantCapabilityAttr>()};
return ClassifyCapabilityFallback;
}
// Returns pair (Kind, Reentrant).
static std::pair<StringRef, bool> classifyCapability(QualType QT) {
// We need to look at the declaration of the type of the value to determine
// which it is. The type should either be a record or a typedef, or a pointer
// or reference thereof.
if (const auto *RD = QT->getAsRecordDecl())
return classifyCapability(*RD);
if (const auto *TT = QT->getAs<TypedefType>())
return classifyCapability(*TT->getDecl());
if (QT->isPointerOrReferenceType())
return classifyCapability(QT->getPointeeType());
return ClassifyCapabilityFallback;
}
CapabilityExpr::CapabilityExpr(const til::SExpr *E, QualType QT, bool Neg) {
const auto &[Kind, Reentrant] = classifyCapability(QT);
*this = CapabilityExpr(E, Kind, Neg, Reentrant);
}
using CallingContext = SExprBuilder::CallingContext;
til::SExpr *SExprBuilder::lookupStmt(const Stmt *S) { return SMap.lookup(S); }
til::SCFG *SExprBuilder::buildCFG(CFGWalker &Walker) {
Walker.walk(*this);
return Scfg;
}
static bool isCalleeArrow(const Expr *E) {
const auto *ME = dyn_cast<MemberExpr>(E->IgnoreParenCasts());
return ME ? ME->isArrow() : false;
}
/// Translate a clang expression in an attribute to a til::SExpr.
/// Constructs the context from D, DeclExp, and SelfDecl.
///
/// \param AttrExp The expression to translate.
/// \param D The declaration to which the attribute is attached.
/// \param DeclExp An expression involving the Decl to which the attribute
/// is attached. E.g. the call to a function.
/// \param Self S-expression to substitute for a \ref CXXThisExpr in a call,
/// or argument to a cleanup function.
CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
const NamedDecl *D,
const Expr *DeclExp,
til::SExpr *Self) {
// If we are processing a raw attribute expression, with no substitutions.
if (!DeclExp && !Self)
return translateAttrExpr(AttrExp, nullptr);
CallingContext Ctx(nullptr, D);
// Examine DeclExp to find SelfArg and FunArgs, which are used to substitute
// for formal parameters when we call buildMutexID later.
if (!DeclExp)
/* We'll use Self. */;
else if (const auto *ME = dyn_cast<MemberExpr>(DeclExp)) {
Ctx.SelfArg = ME->getBase();
Ctx.SelfArrow = ME->isArrow();
} else if (const auto *CE = dyn_cast<CXXMemberCallExpr>(DeclExp)) {
Ctx.SelfArg = CE->getImplicitObjectArgument();
Ctx.SelfArrow = isCalleeArrow(CE->getCallee());
Ctx.NumArgs = CE->getNumArgs();
Ctx.FunArgs = CE->getArgs();
} else if (const auto *CE = dyn_cast<CallExpr>(DeclExp)) {
// Calls to operators that are members need to be treated like member calls.
if (isa<CXXOperatorCallExpr>(CE) && isa<CXXMethodDecl>(D)) {
Ctx.SelfArg = CE->getArg(0);
Ctx.SelfArrow = false;
Ctx.NumArgs = CE->getNumArgs() - 1;
Ctx.FunArgs = CE->getArgs() + 1;
} else {
Ctx.NumArgs = CE->getNumArgs();
Ctx.FunArgs = CE->getArgs();
}
} else if (const auto *CE = dyn_cast<CXXConstructExpr>(DeclExp)) {
Ctx.SelfArg = nullptr; // Will be set below
Ctx.NumArgs = CE->getNumArgs();
Ctx.FunArgs = CE->getArgs();
}
// Usually we want to substitute the self-argument for "this", but lambdas
// are an exception: "this" on or in a lambda call operator doesn't refer
// to the lambda, but to captured "this" in the context it was created in.
// This can happen for operator calls and member calls, so fix it up here.
if (const auto *CMD = dyn_cast<CXXMethodDecl>(D))
if (CMD->getParent()->isLambda())
Ctx.SelfArg = nullptr;
if (Self) {
assert(!Ctx.SelfArg && "Ambiguous self argument");
assert(isa<FunctionDecl>(D) && "Self argument requires function");
if (isa<CXXMethodDecl>(D))
Ctx.SelfArg = Self;
else
Ctx.FunArgs = Self;
// If the attribute has no arguments, then assume the argument is "this".
if (!AttrExp)
return CapabilityExpr(
Self, cast<CXXMethodDecl>(D)->getFunctionObjectParameterType(),
false);
else // For most attributes.
return translateAttrExpr(AttrExp, &Ctx);
}
// If the attribute has no arguments, then assume the argument is "this".
if (!AttrExp)
return translateAttrExpr(cast<const Expr *>(Ctx.SelfArg), nullptr);
else // For most attributes.
return translateAttrExpr(AttrExp, &Ctx);
}
/// Translate a clang expression in an attribute to a til::SExpr.
// This assumes a CallingContext has already been created.
CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
CallingContext *Ctx) {
if (!AttrExp)
return CapabilityExpr();
if (const auto* SLit = dyn_cast<StringLiteral>(AttrExp)) {
if (SLit->getString() == "*")
// The "*" expr is a universal lock, which essentially turns off
// checks until it is removed from the lockset.
return CapabilityExpr(new (Arena) til::Wildcard(), StringRef("wildcard"),
/*Neg=*/false, /*Reentrant=*/false);
else
// Ignore other string literals for now.
return CapabilityExpr();
}
bool Neg = false;
if (const auto *OE = dyn_cast<CXXOperatorCallExpr>(AttrExp)) {
if (OE->getOperator() == OO_Exclaim) {
Neg = true;
AttrExp = OE->getArg(0);
}
}
else if (const auto *UO = dyn_cast<UnaryOperator>(AttrExp)) {
if (UO->getOpcode() == UO_LNot) {
Neg = true;
AttrExp = UO->getSubExpr()->IgnoreImplicit();
}
}
const til::SExpr *E = translate(AttrExp, Ctx);
// Trap mutex expressions like nullptr, or 0.
// Any literal value is nonsense.
if (!E || isa<til::Literal>(E))
return CapabilityExpr();
// Hack to deal with smart pointers -- strip off top-level pointer casts.
if (const auto *CE = dyn_cast<til::Cast>(E)) {
if (CE->castOpcode() == til::CAST_objToPtr)
E = CE->expr();
}
return CapabilityExpr(E, AttrExp->getType(), Neg);
}
til::SExpr *SExprBuilder::translateVariable(const VarDecl *VD,
CallingContext *Ctx) {
assert(VD);
// General recursion guard for x = f(x). If we are already in the process of
// defining VD, use its pre-assignment value to break the cycle.
if (VarsBeingTranslated.contains(VD->getCanonicalDecl()))
return new (Arena) til::LiteralPtr(VD);
// The closure captures state that is updated to correctly translate chains of
// aliases. Restore it when we are done with recursive translation.
llvm::scope_exit Cleanup([&, RestoreClosure = VarsBeingTranslated.empty()
? LookupLocalVarExpr
: nullptr] {
VarsBeingTranslated.erase(VD->getCanonicalDecl());
if (VarsBeingTranslated.empty())
LookupLocalVarExpr = RestoreClosure;
});
VarsBeingTranslated.insert(VD->getCanonicalDecl());
QualType Ty = VD->getType();
if (!VD->isStaticLocal() && Ty->isPointerType()) {
// Substitute local variable aliases with a canonical definition.
if (LookupLocalVarExpr) {
// Attempt to resolve an alias through the more complex local variable map
// lookup. This will fail with complex control-flow graphs (where we
// revert to no alias resolution to retain stable variable names).
if (const Expr *E = LookupLocalVarExpr(VD)) {
til::SExpr *Result = translate(E, Ctx);
// Unsupported expression (such as heap allocations) will be undefined;
// rather than failing here, we simply revert to the pointer being the
// canonical variable.
if (Result && !isa<til::Undefined>(Result))
return Result;
}
}
}
return new (Arena) til::LiteralPtr(VD);
}
// Translate a clang statement or expression to a TIL expression.
// Also performs substitution of variables; Ctx provides the context.
// Dispatches on the type of S.
til::SExpr *SExprBuilder::translate(const Stmt *S, CallingContext *Ctx) {
if (!S)
return nullptr;
// Check if S has already been translated and cached.
// This handles the lookup of SSA names for DeclRefExprs here.
if (til::SExpr *E = lookupStmt(S))
return E;
switch (S->getStmtClass()) {
case Stmt::DeclRefExprClass:
return translateDeclRefExpr(cast<DeclRefExpr>(S), Ctx);
case Stmt::CXXThisExprClass:
return translateCXXThisExpr(cast<CXXThisExpr>(S), Ctx);
case Stmt::MemberExprClass:
return translateMemberExpr(cast<MemberExpr>(S), Ctx);
case Stmt::ObjCIvarRefExprClass:
return translateObjCIVarRefExpr(cast<ObjCIvarRefExpr>(S), Ctx);
case Stmt::CallExprClass:
return translateCallExpr(cast<CallExpr>(S), Ctx);
case Stmt::CXXMemberCallExprClass:
return translateCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), Ctx);
case Stmt::CXXOperatorCallExprClass:
return translateCXXOperatorCallExpr(cast<CXXOperatorCallExpr>(S), Ctx);
case Stmt::UnaryOperatorClass:
return translateUnaryOperator(cast<UnaryOperator>(S), Ctx);
case Stmt::BinaryOperatorClass:
case Stmt::CompoundAssignOperatorClass:
return translateBinaryOperator(cast<BinaryOperator>(S), Ctx);
case Stmt::ArraySubscriptExprClass:
return translateArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Ctx);
case Stmt::ConditionalOperatorClass:
return translateAbstractConditionalOperator(
cast<ConditionalOperator>(S), Ctx);
case Stmt::BinaryConditionalOperatorClass:
return translateAbstractConditionalOperator(
cast<BinaryConditionalOperator>(S), Ctx);
// We treat these as no-ops
case Stmt::ConstantExprClass:
return translate(cast<ConstantExpr>(S)->getSubExpr(), Ctx);
case Stmt::ParenExprClass:
return translate(cast<ParenExpr>(S)->getSubExpr(), Ctx);
case Stmt::ExprWithCleanupsClass:
return translate(cast<ExprWithCleanups>(S)->getSubExpr(), Ctx);
case Stmt::CXXBindTemporaryExprClass:
return translate(cast<CXXBindTemporaryExpr>(S)->getSubExpr(), Ctx);
case Stmt::MaterializeTemporaryExprClass:
return translate(cast<MaterializeTemporaryExpr>(S)->getSubExpr(), Ctx);
// Collect all literals
case Stmt::CharacterLiteralClass:
return new (Arena)
til::LiteralT<char32_t>(cast<CharacterLiteral>(S)->getValue());
case Stmt::CXXNullPtrLiteralExprClass:
case Stmt::GNUNullExprClass:
return new (Arena) til::LiteralT(nullptr);
case Stmt::CXXBoolLiteralExprClass:
return new (Arena) til::LiteralT(cast<CXXBoolLiteralExpr>(S)->getValue());
case Stmt::IntegerLiteralClass: {
const auto *IL = cast<IntegerLiteral>(S);
const auto *BT = cast<BuiltinType>(IL->getType());
const llvm::APInt &Value = IL->getValue();
if (BT->isSignedInteger())
return new (Arena) til::LiteralT(Value.getSExtValue());
else if (BT->isUnsignedInteger())
return new (Arena) til::LiteralT(Value.getZExtValue());
else
llvm_unreachable("Invalid integer type");
}
case Stmt::StringLiteralClass:
return new (Arena) til::LiteralT(cast<StringLiteral>(S)->getString());
case Stmt::ObjCStringLiteralClass:
return new (Arena)
til::LiteralT(cast<ObjCStringLiteral>(S)->getString()->getString());
case Stmt::DeclStmtClass:
return translateDeclStmt(cast<DeclStmt>(S), Ctx);
case Stmt::StmtExprClass:
return translateStmtExpr(cast<StmtExpr>(S), Ctx);
default:
break;
}
if (const auto *CE = dyn_cast<CastExpr>(S))
return translateCastExpr(CE, Ctx);
return new (Arena) til::Undefined(S);
}
til::SExpr *SExprBuilder::translateDeclRefExpr(const DeclRefExpr *DRE,
CallingContext *Ctx) {
const auto *VD = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
// Function parameters require substitution and/or renaming.
if (const auto *PV = dyn_cast<ParmVarDecl>(VD)) {
unsigned I = PV->getFunctionScopeIndex();
const DeclContext *D = PV->getDeclContext();
if (Ctx && Ctx->FunArgs) {
const Decl *Canonical = Ctx->AttrDecl->getCanonicalDecl();
if (isa<FunctionDecl>(D)
? (cast<FunctionDecl>(D)->getCanonicalDecl() == Canonical)
: (cast<ObjCMethodDecl>(D)->getCanonicalDecl() == Canonical)) {
// Substitute call arguments for references to function parameters
if (const Expr *const *FunArgs =
dyn_cast<const Expr *const *>(Ctx->FunArgs)) {
assert(I < Ctx->NumArgs);
return translate(FunArgs[I], Ctx->Prev);
}
assert(I == 0);
return cast<til::SExpr *>(Ctx->FunArgs);
}
}
// Map the param back to the param of the original function declaration
// for consistent comparisons.
VD = isa<FunctionDecl>(D)
? cast<FunctionDecl>(D)->getCanonicalDecl()->getParamDecl(I)
: cast<ObjCMethodDecl>(D)->getCanonicalDecl()->getParamDecl(I);
}
if (const auto *VarD = dyn_cast<VarDecl>(VD))
return translateVariable(VarD, Ctx);
// For non-local variables, treat it as a reference to a named object.
return new (Arena) til::LiteralPtr(VD);
}
til::SExpr *SExprBuilder::translateCXXThisExpr(const CXXThisExpr *TE,
CallingContext *Ctx) {
// Substitute for 'this'
if (Ctx && Ctx->SelfArg) {
if (const auto *SelfArg = dyn_cast<const Expr *>(Ctx->SelfArg))
return translate(SelfArg, Ctx->Prev);
else
return cast<til::SExpr *>(Ctx->SelfArg);
}
assert(SelfVar && "We have no variable for 'this'!");
return SelfVar;
}
static const ValueDecl *getValueDeclFromSExpr(const til::SExpr *E) {
if (const auto *V = dyn_cast<til::Variable>(E))
return V->clangDecl();
if (const auto *Ph = dyn_cast<til::Phi>(E))
return Ph->clangDecl();
if (const auto *P = dyn_cast<til::Project>(E))
return P->clangDecl();
if (const auto *L = dyn_cast<til::LiteralPtr>(E))
return L->clangDecl();
return nullptr;
}
static bool hasAnyPointerType(const til::SExpr *E) {
auto *VD = getValueDeclFromSExpr(E);
if (VD && VD->getType()->isAnyPointerType())
return true;
if (const auto *C = dyn_cast<til::Cast>(E))
return C->castOpcode() == til::CAST_objToPtr;
return false;
}
// Grab the very first declaration of virtual method D
static const CXXMethodDecl *getFirstVirtualDecl(const CXXMethodDecl *D) {
while (true) {
D = D->getCanonicalDecl();
auto OverriddenMethods = D->overridden_methods();
if (OverriddenMethods.begin() == OverriddenMethods.end())
return D; // Method does not override anything
// FIXME: this does not work with multiple inheritance.
D = *OverriddenMethods.begin();
}
return nullptr;
}
til::SExpr *SExprBuilder::translateMemberExpr(const MemberExpr *ME,
CallingContext *Ctx) {
til::SExpr *BE = translate(ME->getBase(), Ctx);
til::SExpr *E = new (Arena) til::SApply(BE);
const auto *D = cast<ValueDecl>(ME->getMemberDecl()->getCanonicalDecl());
if (const auto *VD = dyn_cast<CXXMethodDecl>(D))
D = getFirstVirtualDecl(VD);
til::Project *P = new (Arena) til::Project(E, D);
if (hasAnyPointerType(BE))
P->setArrow(true);
return P;
}
til::SExpr *SExprBuilder::translateObjCIVarRefExpr(const ObjCIvarRefExpr *IVRE,
CallingContext *Ctx) {
til::SExpr *BE = translate(IVRE->getBase(), Ctx);
til::SExpr *E = new (Arena) til::SApply(BE);
const auto *D = cast<ObjCIvarDecl>(IVRE->getDecl()->getCanonicalDecl());
til::Project *P = new (Arena) til::Project(E, D);
if (hasAnyPointerType(BE))
P->setArrow(true);
return P;
}
til::SExpr *SExprBuilder::translateCallExpr(const CallExpr *CE,
CallingContext *Ctx,
const Expr *SelfE) {
if (CapabilityExprMode) {
// Handle LOCK_RETURNED
if (const FunctionDecl *FD = CE->getDirectCallee()) {
FD = FD->getMostRecentDecl();
if (LockReturnedAttr *At = FD->getAttr<LockReturnedAttr>()) {
CallingContext LRCallCtx(Ctx);
LRCallCtx.AttrDecl = CE->getDirectCallee();
LRCallCtx.SelfArg = SelfE;
LRCallCtx.NumArgs = CE->getNumArgs();
LRCallCtx.FunArgs = CE->getArgs();
return const_cast<til::SExpr *>(
translateAttrExpr(At->getArg(), &LRCallCtx).sexpr());
}
}
}
til::SExpr *E = translate(CE->getCallee(), Ctx);
for (const auto *Arg : CE->arguments()) {
til::SExpr *A = translate(Arg, Ctx);
E = new (Arena) til::Apply(E, A);
}
return new (Arena) til::Call(E, CE);
}
til::SExpr *SExprBuilder::translateCXXMemberCallExpr(
const CXXMemberCallExpr *ME, CallingContext *Ctx) {
if (CapabilityExprMode) {
// Ignore calls to get() on smart pointers.
if (ME->getMethodDecl()->getNameAsString() == "get" &&
ME->getNumArgs() == 0) {
auto *E = translate(ME->getImplicitObjectArgument(), Ctx);
return new (Arena) til::Cast(til::CAST_objToPtr, E);
// return E;
}
}
return translateCallExpr(cast<CallExpr>(ME), Ctx,
ME->getImplicitObjectArgument());
}
til::SExpr *SExprBuilder::translateCXXOperatorCallExpr(
const CXXOperatorCallExpr *OCE, CallingContext *Ctx) {
if (CapabilityExprMode) {
// Ignore operator * and operator -> on smart pointers.
OverloadedOperatorKind k = OCE->getOperator();
if (k == OO_Star || k == OO_Arrow) {
auto *E = translate(OCE->getArg(0), Ctx);
return new (Arena) til::Cast(til::CAST_objToPtr, E);
// return E;
}
}
return translateCallExpr(cast<CallExpr>(OCE), Ctx);
}
til::SExpr *SExprBuilder::translateUnaryOperator(const UnaryOperator *UO,
CallingContext *Ctx) {
switch (UO->getOpcode()) {
case UO_PostInc:
case UO_PostDec:
case UO_PreInc:
case UO_PreDec:
return new (Arena) til::Undefined(UO);
case UO_AddrOf:
if (CapabilityExprMode) {
// interpret &Graph::mu_ as an existential.
if (const auto *DRE = dyn_cast<DeclRefExpr>(UO->getSubExpr())) {
if (DRE->getDecl()->isCXXInstanceMember()) {
// This is a pointer-to-member expression, e.g. &MyClass::mu_.
// We interpret this syntax specially, as a wildcard.
auto *W = new (Arena) til::Wildcard();
return new (Arena) til::Project(W, DRE->getDecl());
}
}
}
// otherwise, & is a no-op
return translate(UO->getSubExpr(), Ctx);
// We treat these as no-ops
case UO_Deref:
case UO_Plus:
return translate(UO->getSubExpr(), Ctx);
case UO_Minus:
return new (Arena)
til::UnaryOp(til::UOP_Minus, translate(UO->getSubExpr(), Ctx));
case UO_Not:
return new (Arena)
til::UnaryOp(til::UOP_BitNot, translate(UO->getSubExpr(), Ctx));
case UO_LNot:
return new (Arena)
til::UnaryOp(til::UOP_LogicNot, translate(UO->getSubExpr(), Ctx));
// Currently unsupported
case UO_Real:
case UO_Imag:
case UO_Extension:
case UO_Coawait:
return new (Arena) til::Undefined(UO);
}
return new (Arena) til::Undefined(UO);
}
til::SExpr *SExprBuilder::translateBinOp(til::TIL_BinaryOpcode Op,
const BinaryOperator *BO,
CallingContext *Ctx, bool Reverse) {
til::SExpr *E0 = translate(BO->getLHS(), Ctx);
til::SExpr *E1 = translate(BO->getRHS(), Ctx);
if (Reverse)
return new (Arena) til::BinaryOp(Op, E1, E0);
else
return new (Arena) til::BinaryOp(Op, E0, E1);
}
til::SExpr *SExprBuilder::translateBinAssign(til::TIL_BinaryOpcode Op,
const BinaryOperator *BO,
CallingContext *Ctx,
bool Assign) {
const Expr *LHS = BO->getLHS();
const Expr *RHS = BO->getRHS();
til::SExpr *E0 = translate(LHS, Ctx);
til::SExpr *E1 = translate(RHS, Ctx);
const ValueDecl *VD = nullptr;
til::SExpr *CV = nullptr;
if (const auto *DRE = dyn_cast<DeclRefExpr>(LHS)) {
VD = DRE->getDecl();
CV = lookupVarDecl(VD);
}
if (!Assign) {
til::SExpr *Arg = CV ? CV : new (Arena) til::Load(E0);
E1 = new (Arena) til::BinaryOp(Op, Arg, E1);
E1 = addStatement(E1, nullptr, VD);
}
if (VD && CV)
return updateVarDecl(VD, E1);
return new (Arena) til::Store(E0, E1);
}
til::SExpr *SExprBuilder::translateBinaryOperator(const BinaryOperator *BO,
CallingContext *Ctx) {
switch (BO->getOpcode()) {
case BO_PtrMemD:
case BO_PtrMemI:
return new (Arena) til::Undefined(BO);
case BO_Mul: return translateBinOp(til::BOP_Mul, BO, Ctx);
case BO_Div: return translateBinOp(til::BOP_Div, BO, Ctx);
case BO_Rem: return translateBinOp(til::BOP_Rem, BO, Ctx);
case BO_Add: return translateBinOp(til::BOP_Add, BO, Ctx);
case BO_Sub: return translateBinOp(til::BOP_Sub, BO, Ctx);
case BO_Shl: return translateBinOp(til::BOP_Shl, BO, Ctx);
case BO_Shr: return translateBinOp(til::BOP_Shr, BO, Ctx);
case BO_LT: return translateBinOp(til::BOP_Lt, BO, Ctx);
case BO_GT: return translateBinOp(til::BOP_Lt, BO, Ctx, true);
case BO_LE: return translateBinOp(til::BOP_Leq, BO, Ctx);
case BO_GE: return translateBinOp(til::BOP_Leq, BO, Ctx, true);
case BO_EQ: return translateBinOp(til::BOP_Eq, BO, Ctx);
case BO_NE: return translateBinOp(til::BOP_Neq, BO, Ctx);
case BO_Cmp: return translateBinOp(til::BOP_Cmp, BO, Ctx);
case BO_And: return translateBinOp(til::BOP_BitAnd, BO, Ctx);
case BO_Xor: return translateBinOp(til::BOP_BitXor, BO, Ctx);
case BO_Or: return translateBinOp(til::BOP_BitOr, BO, Ctx);
case BO_LAnd: return translateBinOp(til::BOP_LogicAnd, BO, Ctx);
case BO_LOr: return translateBinOp(til::BOP_LogicOr, BO, Ctx);
case BO_Assign: return translateBinAssign(til::BOP_Eq, BO, Ctx, true);
case BO_MulAssign: return translateBinAssign(til::BOP_Mul, BO, Ctx);
case BO_DivAssign: return translateBinAssign(til::BOP_Div, BO, Ctx);
case BO_RemAssign: return translateBinAssign(til::BOP_Rem, BO, Ctx);
case BO_AddAssign: return translateBinAssign(til::BOP_Add, BO, Ctx);
case BO_SubAssign: return translateBinAssign(til::BOP_Sub, BO, Ctx);
case BO_ShlAssign: return translateBinAssign(til::BOP_Shl, BO, Ctx);
case BO_ShrAssign: return translateBinAssign(til::BOP_Shr, BO, Ctx);
case BO_AndAssign: return translateBinAssign(til::BOP_BitAnd, BO, Ctx);
case BO_XorAssign: return translateBinAssign(til::BOP_BitXor, BO, Ctx);
case BO_OrAssign: return translateBinAssign(til::BOP_BitOr, BO, Ctx);
case BO_Comma:
// The clang CFG should have already processed both sides.
return translate(BO->getRHS(), Ctx);
}
return new (Arena) til::Undefined(BO);
}
til::SExpr *SExprBuilder::translateCastExpr(const CastExpr *CE,
CallingContext *Ctx) {
CastKind K = CE->getCastKind();
switch (K) {
case CK_LValueToRValue: {
if (const auto *DRE = dyn_cast<DeclRefExpr>(CE->getSubExpr())) {
til::SExpr *E0 = lookupVarDecl(DRE->getDecl());
if (E0)
return E0;
}
til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
return E0;
// FIXME!! -- get Load working properly
// return new (Arena) til::Load(E0);
}
case CK_NoOp:
case CK_DerivedToBase:
case CK_UncheckedDerivedToBase:
case CK_ArrayToPointerDecay:
case CK_FunctionToPointerDecay: {
til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
return E0;
}
default: {
// FIXME: handle different kinds of casts.
til::SExpr *E0 = translate(CE->getSubExpr(), Ctx);
if (CapabilityExprMode)
return E0;
return new (Arena) til::Cast(til::CAST_none, E0);
}
}
}
til::SExpr *
SExprBuilder::translateArraySubscriptExpr(const ArraySubscriptExpr *E,
CallingContext *Ctx) {
til::SExpr *E0 = translate(E->getBase(), Ctx);
til::SExpr *E1 = translate(E->getIdx(), Ctx);
return new (Arena) til::ArrayIndex(E0, E1);
}
til::SExpr *
SExprBuilder::translateAbstractConditionalOperator(
const AbstractConditionalOperator *CO, CallingContext *Ctx) {
auto *C = translate(CO->getCond(), Ctx);
auto *T = translate(CO->getTrueExpr(), Ctx);
auto *E = translate(CO->getFalseExpr(), Ctx);
return new (Arena) til::IfThenElse(C, T, E);
}
til::SExpr *
SExprBuilder::translateDeclStmt(const DeclStmt *S, CallingContext *Ctx) {
DeclGroupRef DGrp = S->getDeclGroup();
for (auto *I : DGrp) {
if (auto *VD = dyn_cast_or_null<VarDecl>(I)) {
Expr *E = VD->getInit();
til::SExpr* SE = translate(E, Ctx);
// Add local variables with trivial type to the variable map
QualType T = VD->getType();
if (T.isTrivialType(VD->getASTContext()))
return addVarDecl(VD, SE);
else {
// TODO: add alloca
}
}
}
return nullptr;
}
til::SExpr *SExprBuilder::translateStmtExpr(const StmtExpr *SE,
CallingContext *Ctx) {
// The value of a statement expression is the value of the last statement,
// which must be an expression.
const CompoundStmt *CS = SE->getSubStmt();
return CS->body_empty() ? new (Arena) til::Undefined(SE)
: translate(CS->body_back(), Ctx);
}
// If (E) is non-trivial, then add it to the current basic block, and
// update the statement map so that S refers to E. Returns a new variable
// that refers to E.
// If E is trivial returns E.
til::SExpr *SExprBuilder::addStatement(til::SExpr* E, const Stmt *S,
const ValueDecl *VD) {
if (!E || !CurrentBB || E->block() || til::ThreadSafetyTIL::isTrivial(E))
return E;
if (VD)
E = new (Arena) til::Variable(E, VD);
CurrentInstructions.push_back(E);
if (S)
insertStmt(S, E);
return E;
}
// Returns the current value of VD, if known, and nullptr otherwise.
til::SExpr *SExprBuilder::lookupVarDecl(const ValueDecl *VD) {
auto It = LVarIdxMap.find(VD);
if (It != LVarIdxMap.end()) {
assert(CurrentLVarMap[It->second].first == VD);
return CurrentLVarMap[It->second].second;
}
return nullptr;
}
// if E is a til::Variable, update its clangDecl.
static void maybeUpdateVD(til::SExpr *E, const ValueDecl *VD) {
if (!E)
return;
if (auto *V = dyn_cast<til::Variable>(E)) {
if (!V->clangDecl())
V->setClangDecl(VD);
}
}
// Adds a new variable declaration.
til::SExpr *SExprBuilder::addVarDecl(const ValueDecl *VD, til::SExpr *E) {
maybeUpdateVD(E, VD);
LVarIdxMap.insert(std::make_pair(VD, CurrentLVarMap.size()));
CurrentLVarMap.makeWritable();
CurrentLVarMap.push_back(std::make_pair(VD, E));
return E;
}
// Updates a current variable declaration. (E.g. by assignment)
til::SExpr *SExprBuilder::updateVarDecl(const ValueDecl *VD, til::SExpr *E) {
maybeUpdateVD(E, VD);
auto It = LVarIdxMap.find(VD);
if (It == LVarIdxMap.end()) {
til::SExpr *Ptr = new (Arena) til::LiteralPtr(VD);
til::SExpr *St = new (Arena) til::Store(Ptr, E);
return St;
}
CurrentLVarMap.makeWritable();
CurrentLVarMap.elem(It->second).second = E;
return E;
}
// Make a Phi node in the current block for the i^th variable in CurrentVarMap.
// If E != null, sets Phi[CurrentBlockInfo->ArgIndex] = E.
// If E == null, this is a backedge and will be set later.
void SExprBuilder::makePhiNodeVar(unsigned i, unsigned NPreds, til::SExpr *E) {
unsigned ArgIndex = CurrentBlockInfo->ProcessedPredecessors;
assert(ArgIndex > 0 && ArgIndex < NPreds);
til::SExpr *CurrE = CurrentLVarMap[i].second;
if (CurrE->block() == CurrentBB) {
// We already have a Phi node in the current block,
// so just add the new variable to the Phi node.
auto *Ph = dyn_cast<til::Phi>(CurrE);
assert(Ph && "Expecting Phi node.");
if (E)
Ph->values()[ArgIndex] = E;
return;
}
// Make a new phi node: phi(..., E)
// All phi args up to the current index are set to the current value.
til::Phi *Ph = new (Arena) til::Phi(Arena, NPreds);
Ph->values().setValues(NPreds, nullptr);
for (unsigned PIdx = 0; PIdx < ArgIndex; ++PIdx)
Ph->values()[PIdx] = CurrE;
if (E)
Ph->values()[ArgIndex] = E;
Ph->setClangDecl(CurrentLVarMap[i].first);
// If E is from a back-edge, or either E or CurrE are incomplete, then
// mark this node as incomplete; we may need to remove it later.
if (!E || isIncompletePhi(E) || isIncompletePhi(CurrE))
Ph->setStatus(til::Phi::PH_Incomplete);
// Add Phi node to current block, and update CurrentLVarMap[i]
CurrentArguments.push_back(Ph);
if (Ph->status() == til::Phi::PH_Incomplete)
IncompleteArgs.push_back(Ph);
CurrentLVarMap.makeWritable();
CurrentLVarMap.elem(i).second = Ph;
}
// Merge values from Map into the current variable map.
// This will construct Phi nodes in the current basic block as necessary.
void SExprBuilder::mergeEntryMap(LVarDefinitionMap Map) {
assert(CurrentBlockInfo && "Not processing a block!");
if (!CurrentLVarMap.valid()) {
// Steal Map, using copy-on-write.
CurrentLVarMap = std::move(Map);
return;
}
if (CurrentLVarMap.sameAs(Map))
return; // Easy merge: maps from different predecessors are unchanged.
unsigned NPreds = CurrentBB->numPredecessors();
unsigned ESz = CurrentLVarMap.size();
unsigned MSz = Map.size();
unsigned Sz = std::min(ESz, MSz);
for (unsigned i = 0; i < Sz; ++i) {
if (CurrentLVarMap[i].first != Map[i].first) {
// We've reached the end of variables in common.
CurrentLVarMap.makeWritable();
CurrentLVarMap.downsize(i);
break;
}
if (CurrentLVarMap[i].second != Map[i].second)
makePhiNodeVar(i, NPreds, Map[i].second);
}
if (ESz > MSz) {
CurrentLVarMap.makeWritable();
CurrentLVarMap.downsize(Map.size());
}
}
// Merge a back edge into the current variable map.
// This will create phi nodes for all variables in the variable map.
void SExprBuilder::mergeEntryMapBackEdge() {
// We don't have definitions for variables on the backedge, because we
// haven't gotten that far in the CFG. Thus, when encountering a back edge,
// we conservatively create Phi nodes for all variables. Unnecessary Phi
// nodes will be marked as incomplete, and stripped out at the end.
//
// An Phi node is unnecessary if it only refers to itself and one other
// variable, e.g. x = Phi(y, y, x) can be reduced to x = y.
assert(CurrentBlockInfo && "Not processing a block!");
if (CurrentBlockInfo->HasBackEdges)
return;
CurrentBlockInfo->HasBackEdges = true;
CurrentLVarMap.makeWritable();
unsigned Sz = CurrentLVarMap.size();
unsigned NPreds = CurrentBB->numPredecessors();
for (unsigned i = 0; i < Sz; ++i)
makePhiNodeVar(i, NPreds, nullptr);
}
// Update the phi nodes that were initially created for a back edge
// once the variable definitions have been computed.
// I.e., merge the current variable map into the phi nodes for Blk.
void SExprBuilder::mergePhiNodesBackEdge(const CFGBlock *Blk) {
til::BasicBlock *BB = lookupBlock(Blk);
unsigned ArgIndex = BBInfo[Blk->getBlockID()].ProcessedPredecessors;
assert(ArgIndex > 0 && ArgIndex < BB->numPredecessors());
for (til::SExpr *PE : BB->arguments()) {
auto *Ph = dyn_cast_or_null<til::Phi>(PE);
assert(Ph && "Expecting Phi Node.");
assert(Ph->values()[ArgIndex] == nullptr && "Wrong index for back edge.");
til::SExpr *E = lookupVarDecl(Ph->clangDecl());
assert(E && "Couldn't find local variable for Phi node.");
Ph->values()[ArgIndex] = E;
}
}
void SExprBuilder::enterCFG(CFG *Cfg, const NamedDecl *D,
const CFGBlock *First) {
// Perform initial setup operations.
unsigned NBlocks = Cfg->getNumBlockIDs();
Scfg = new (Arena) til::SCFG(Arena, NBlocks);
// allocate all basic blocks immediately, to handle forward references.
BBInfo.resize(NBlocks);
BlockMap.resize(NBlocks, nullptr);
// create map from clang blockID to til::BasicBlocks
for (auto *B : *Cfg) {
auto *BB = new (Arena) til::BasicBlock(Arena);
BB->reserveInstructions(B->size());
BlockMap[B->getBlockID()] = BB;
}
CurrentBB = lookupBlock(&Cfg->getEntry());
auto Parms = isa<ObjCMethodDecl>(D) ? cast<ObjCMethodDecl>(D)->parameters()
: cast<FunctionDecl>(D)->parameters();
for (auto *Pm : Parms) {
QualType T = Pm->getType();
if (!T.isTrivialType(Pm->getASTContext()))
continue;
// Add parameters to local variable map.
// FIXME: right now we emulate params with loads; that should be fixed.
til::SExpr *Lp = new (Arena) til::LiteralPtr(Pm);
til::SExpr *Ld = new (Arena) til::Load(Lp);
til::SExpr *V = addStatement(Ld, nullptr, Pm);
addVarDecl(Pm, V);
}
}
void SExprBuilder::enterCFGBlock(const CFGBlock *B) {
// Initialize TIL basic block and add it to the CFG.
CurrentBB = lookupBlock(B);
CurrentBB->reservePredecessors(B->pred_size());
Scfg->add(CurrentBB);
CurrentBlockInfo = &BBInfo[B->getBlockID()];
// CurrentLVarMap is moved to ExitMap on block exit.
// FIXME: the entry block will hold function parameters.
// assert(!CurrentLVarMap.valid() && "CurrentLVarMap already initialized.");
}
void SExprBuilder::handlePredecessor(const CFGBlock *Pred) {
// Compute CurrentLVarMap on entry from ExitMaps of predecessors
CurrentBB->addPredecessor(BlockMap[Pred->getBlockID()]);
BlockInfo *PredInfo = &BBInfo[Pred->getBlockID()];
assert(PredInfo->UnprocessedSuccessors > 0);
if (--PredInfo->UnprocessedSuccessors == 0)
mergeEntryMap(std::move(PredInfo->ExitMap));
else
mergeEntryMap(PredInfo->ExitMap.clone());
++CurrentBlockInfo->ProcessedPredecessors;
}
void SExprBuilder::handlePredecessorBackEdge(const CFGBlock *Pred) {
mergeEntryMapBackEdge();
}
void SExprBuilder::enterCFGBlockBody(const CFGBlock *B) {
// The merge*() methods have created arguments.
// Push those arguments onto the basic block.
CurrentBB->arguments().reserve(
static_cast<unsigned>(CurrentArguments.size()), Arena);
for (auto *A : CurrentArguments)
CurrentBB->addArgument(A);
}
void SExprBuilder::handleStatement(const Stmt *S) {
til::SExpr *E = translate(S, nullptr);
addStatement(E, S);
}
void SExprBuilder::handleDestructorCall(const VarDecl *VD,
const CXXDestructorDecl *DD) {
til::SExpr *Sf = new (Arena) til::LiteralPtr(VD);
til::SExpr *Dr = new (Arena) til::LiteralPtr(DD);
til::SExpr *Ap = new (Arena) til::Apply(Dr, Sf);
til::SExpr *E = new (Arena) til::Call(Ap);
addStatement(E, nullptr);
}
void SExprBuilder::exitCFGBlockBody(const CFGBlock *B) {
CurrentBB->instructions().reserve(
static_cast<unsigned>(CurrentInstructions.size()), Arena);
for (auto *V : CurrentInstructions)
CurrentBB->addInstruction(V);
// Create an appropriate terminator
unsigned N = B->succ_size();
auto It = B->succ_begin();
if (N == 1) {
til::BasicBlock *BB = *It ? lookupBlock(*It) : nullptr;
// TODO: set index
unsigned Idx = BB ? BB->findPredecessorIndex(CurrentBB) : 0;
auto *Tm = new (Arena) til::Goto(BB, Idx);
CurrentBB->setTerminator(Tm);
}
else if (N == 2) {
til::SExpr *C = translate(B->getTerminatorCondition(true), nullptr);
til::BasicBlock *BB1 = *It ? lookupBlock(*It) : nullptr;
++It;
til::BasicBlock *BB2 = *It ? lookupBlock(*It) : nullptr;
// FIXME: make sure these aren't critical edges.
auto *Tm = new (Arena) til::Branch(C, BB1, BB2);
CurrentBB->setTerminator(Tm);
}
}
void SExprBuilder::handleSuccessor(const CFGBlock *Succ) {
++CurrentBlockInfo->UnprocessedSuccessors;
}
void SExprBuilder::handleSuccessorBackEdge(const CFGBlock *Succ) {
mergePhiNodesBackEdge(Succ);
++BBInfo[Succ->getBlockID()].ProcessedPredecessors;
}
void SExprBuilder::exitCFGBlock(const CFGBlock *B) {
CurrentArguments.clear();
CurrentInstructions.clear();
CurrentBlockInfo->ExitMap = std::move(CurrentLVarMap);
CurrentBB = nullptr;
CurrentBlockInfo = nullptr;
}
void SExprBuilder::exitCFG(const CFGBlock *Last) {
for (auto *Ph : IncompleteArgs) {
if (Ph->status() == til::Phi::PH_Incomplete)
simplifyIncompleteArg(Ph);
}
CurrentArguments.clear();
CurrentInstructions.clear();
IncompleteArgs.clear();
}
#ifndef NDEBUG
namespace {
class TILPrinter :
public til::PrettyPrinter<TILPrinter, llvm::raw_ostream> {};
} // namespace
namespace clang {
namespace threadSafety {
void printSCFG(CFGWalker &Walker) {
llvm::BumpPtrAllocator Bpa;
til::MemRegionRef Arena(&Bpa);
SExprBuilder SxBuilder(Arena);
til::SCFG *Scfg = SxBuilder.buildCFG(Walker);
TILPrinter::print(Scfg, llvm::errs());
}
} // namespace threadSafety
} // namespace clang
#endif // NDEBUG