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llvm-project/clang/lib/Analysis/ThreadSafetyCommon.cpp

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//===- 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/StringRef.h"
#include "llvm/Support/Casting.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 cast<IntegerLiteral>(CE)->getValue().toString(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;
}
using CallingContext = SExprBuilder::CallingContext;
til::SExpr *SExprBuilder::lookupStmt(const Stmt *S) {
auto It = SMap.find(S);
if (It != SMap.end())
return It->second;
return nullptr;
}
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.
CapabilityExpr SExprBuilder::translateAttrExpr(const Expr *AttrExp,
const NamedDecl *D,
const Expr *DeclExp,
VarDecl *SelfDecl) {
// If we are processing a raw attribute expression, with no substitutions.
if (!DeclExp)
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 (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)) {
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();
} else if (D && isa<CXXDestructorDecl>(D)) {
// There's no such thing as a "destructor call" in the AST.
Ctx.SelfArg = DeclExp;
}
// Hack to handle constructors, where self cannot be recovered from
// the expression.
if (SelfDecl && !Ctx.SelfArg) {
DeclRefExpr SelfDRE(SelfDecl->getASTContext(), SelfDecl, false,
SelfDecl->getType(), VK_LValue,
SelfDecl->getLocation());
Ctx.SelfArg = &SelfDRE;
// If the attribute has no arguments, then assume the argument is "this".
if (!AttrExp)
return translateAttrExpr(Ctx.SelfArg, nullptr);
else // For most attributes.
return translateAttrExpr(AttrExp, &Ctx);
}
// If the attribute has no arguments, then assume the argument is "this".
if (!AttrExp)
return translateAttrExpr(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(nullptr, false);
if (const auto* SLit = dyn_cast<StringLiteral>(AttrExp)) {
if (SLit->getString() == StringRef("*"))
// The "*" expr is a universal lock, which essentially turns off
// checks until it is removed from the lockset.
return CapabilityExpr(new (Arena) til::Wildcard(), false);
else
// Ignore other string literals for now.
return CapabilityExpr(nullptr, false);
}
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();
}
}
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(nullptr, false);
// 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)
return CapabilityExpr(CE->expr(), Neg);
}
return CapabilityExpr(E, Neg);
}
// 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:
case Stmt::CXXNullPtrLiteralExprClass:
case Stmt::GNUNullExprClass:
case Stmt::CXXBoolLiteralExprClass:
case Stmt::FloatingLiteralClass:
case Stmt::ImaginaryLiteralClass:
case Stmt::IntegerLiteralClass:
case Stmt::StringLiteralClass:
case Stmt::ObjCStringLiteralClass:
return new (Arena) til::Literal(cast<Expr>(S));
case Stmt::DeclStmtClass:
return translateDeclStmt(cast<DeclStmt>(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
assert(I < Ctx->NumArgs);
return translate(Ctx->FunArgs[I], Ctx->Prev);
}
}
// 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);
}
// 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)
return translate(Ctx->SelfArg, Ctx->Prev);
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;
}
// 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();
}
/*
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
*/
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