head 1.1; branch 1.1.1; access; symbols netbsd-11-0-RC4:1.1.1.6 netbsd-11-0-RC3:1.1.1.6 netbsd-11-0-RC2:1.1.1.6 netbsd-11-0-RC1:1.1.1.6 perseant-exfatfs-base-20250801:1.1.1.6 netbsd-11:1.1.1.6.0.10 netbsd-11-base:1.1.1.6 netbsd-10-1-RELEASE:1.1.1.6 perseant-exfatfs-base-20240630:1.1.1.6 perseant-exfatfs:1.1.1.6.0.8 perseant-exfatfs-base:1.1.1.6 netbsd-8-3-RELEASE:1.1.1.4 netbsd-9-4-RELEASE:1.1.1.5 netbsd-10-0-RELEASE:1.1.1.6 netbsd-10-0-RC6:1.1.1.6 netbsd-10-0-RC5:1.1.1.6 netbsd-10-0-RC4:1.1.1.6 netbsd-10-0-RC3:1.1.1.6 netbsd-10-0-RC2:1.1.1.6 netbsd-10-0-RC1:1.1.1.6 netbsd-10:1.1.1.6.0.6 netbsd-10-base:1.1.1.6 netbsd-9-3-RELEASE:1.1.1.5 cjep_sun2x:1.1.1.6.0.4 cjep_sun2x-base:1.1.1.6 cjep_staticlib_x-base1:1.1.1.6 netbsd-9-2-RELEASE:1.1.1.5 cjep_staticlib_x:1.1.1.6.0.2 cjep_staticlib_x-base:1.1.1.6 netbsd-9-1-RELEASE:1.1.1.5 phil-wifi-20200421:1.1.1.6 phil-wifi-20200411:1.1.1.6 phil-wifi-20200406:1.1.1.6 netbsd-8-2-RELEASE:1.1.1.4 netbsd-9-0-RELEASE:1.1.1.5 netbsd-9-0-RC2:1.1.1.5 netbsd-9-0-RC1:1.1.1.5 netbsd-9:1.1.1.5.0.6 netbsd-9-base:1.1.1.5 phil-wifi-20190609:1.1.1.5 netbsd-8-1-RELEASE:1.1.1.4 netbsd-8-1-RC1:1.1.1.4 pgoyette-compat-merge-20190127:1.1.1.5 pgoyette-compat-20190127:1.1.1.5 pgoyette-compat-20190118:1.1.1.5 pgoyette-compat-1226:1.1.1.5 pgoyette-compat-1126:1.1.1.5 pgoyette-compat-1020:1.1.1.5 pgoyette-compat-0930:1.1.1.5 pgoyette-compat-0906:1.1.1.5 netbsd-7-2-RELEASE:1.1.1.2 pgoyette-compat-0728:1.1.1.5 clang-337282:1.1.1.5 netbsd-8-0-RELEASE:1.1.1.4 phil-wifi:1.1.1.5.0.4 phil-wifi-base:1.1.1.5 pgoyette-compat-0625:1.1.1.5 netbsd-8-0-RC2:1.1.1.4 pgoyette-compat-0521:1.1.1.5 pgoyette-compat-0502:1.1.1.5 pgoyette-compat-0422:1.1.1.5 netbsd-8-0-RC1:1.1.1.4 pgoyette-compat-0415:1.1.1.5 pgoyette-compat-0407:1.1.1.5 pgoyette-compat-0330:1.1.1.5 pgoyette-compat-0322:1.1.1.5 pgoyette-compat-0315:1.1.1.5 netbsd-7-1-2-RELEASE:1.1.1.2 pgoyette-compat:1.1.1.5.0.2 pgoyette-compat-base:1.1.1.5 netbsd-7-1-1-RELEASE:1.1.1.2 clang-319952:1.1.1.5 matt-nb8-mediatek:1.1.1.4.0.10 matt-nb8-mediatek-base:1.1.1.4 clang-309604:1.1.1.5 perseant-stdc-iso10646:1.1.1.4.0.8 perseant-stdc-iso10646-base:1.1.1.4 netbsd-8:1.1.1.4.0.6 netbsd-8-base:1.1.1.4 prg-localcount2-base3:1.1.1.4 prg-localcount2-base2:1.1.1.4 prg-localcount2-base1:1.1.1.4 prg-localcount2:1.1.1.4.0.4 prg-localcount2-base:1.1.1.4 pgoyette-localcount-20170426:1.1.1.4 bouyer-socketcan-base1:1.1.1.4 pgoyette-localcount-20170320:1.1.1.4 netbsd-7-1:1.1.1.2.0.10 netbsd-7-1-RELEASE:1.1.1.2 netbsd-7-1-RC2:1.1.1.2 clang-294123:1.1.1.4 netbsd-7-nhusb-base-20170116:1.1.1.2 bouyer-socketcan:1.1.1.4.0.2 bouyer-socketcan-base:1.1.1.4 clang-291444:1.1.1.4 pgoyette-localcount-20170107:1.1.1.3 netbsd-7-1-RC1:1.1.1.2 pgoyette-localcount-20161104:1.1.1.3 netbsd-7-0-2-RELEASE:1.1.1.2 localcount-20160914:1.1.1.3 netbsd-7-nhusb:1.1.1.2.0.8 netbsd-7-nhusb-base:1.1.1.2 clang-280599:1.1.1.3 pgoyette-localcount-20160806:1.1.1.3 pgoyette-localcount-20160726:1.1.1.3 pgoyette-localcount:1.1.1.3.0.2 pgoyette-localcount-base:1.1.1.3 netbsd-7-0-1-RELEASE:1.1.1.2 clang-261930:1.1.1.3 netbsd-7-0:1.1.1.2.0.6 netbsd-7-0-RELEASE:1.1.1.2 netbsd-7-0-RC3:1.1.1.2 netbsd-7-0-RC2:1.1.1.2 netbsd-7-0-RC1:1.1.1.2 clang-237755:1.1.1.2 clang-232565:1.1.1.2 clang-227398:1.1.1.2 tls-maxphys-base:1.1.1.2 tls-maxphys:1.1.1.2.0.4 netbsd-7:1.1.1.2.0.2 netbsd-7-base:1.1.1.2 clang-215315:1.1.1.2 clang-209886:1.1.1.2 yamt-pagecache:1.1.1.1.0.4 yamt-pagecache-base9:1.1.1.1 tls-earlyentropy:1.1.1.1.0.2 tls-earlyentropy-base:1.1.1.2 riastradh-xf86-video-intel-2-7-1-pre-2-21-15:1.1.1.1 riastradh-drm2-base3:1.1.1.1 clang-202566:1.1.1.1 clang-201163:1.1.1.1 clang-199312:1.1.1.1 clang-198450:1.1.1.1 clang-196603:1.1.1.1 clang-195771:1.1.1.1 LLVM:1.1.1; locks; strict; comment @// @; 1.1 date 2013.11.28.14.14.49; author joerg; state Exp; branches 1.1.1.1; next ; commitid ow8OybrawrB1f3fx; 1.1.1.1 date 2013.11.28.14.14.49; author joerg; state Exp; branches 1.1.1.1.2.1 1.1.1.1.4.1; next 1.1.1.2; commitid ow8OybrawrB1f3fx; 1.1.1.2 date 2014.05.30.18.14.40; author joerg; state Exp; branches 1.1.1.2.4.1; next 1.1.1.3; commitid 8q0kdlBlCn09GACx; 1.1.1.3 date 2016.02.27.22.11.54; author joerg; state Exp; branches 1.1.1.3.2.1; next 1.1.1.4; commitid tIimz3oDlh1NpBWy; 1.1.1.4 date 2017.01.11.10.34.43; author joerg; state Exp; branches; next 1.1.1.5; commitid CNnUNfII1jgNmxBz; 1.1.1.5 date 2017.08.01.19.35.37; author joerg; state Exp; branches 1.1.1.5.4.1; next 1.1.1.6; commitid pMuDy65V0VicSx1A; 1.1.1.6 date 2019.11.13.22.19.20; author joerg; state dead; branches; next ; commitid QD8YATxuNG34YJKB; 1.1.1.1.2.1 date 2014.08.10.07.08.07; author tls; state Exp; branches; next ; commitid t01A1TLTYxkpGMLx; 1.1.1.1.4.1 date 2013.11.28.14.14.49; author yamt; state dead; branches; next 1.1.1.1.4.2; commitid WSrDtL5nYAUyiyBx; 1.1.1.1.4.2 date 2014.05.22.16.18.26; author yamt; state Exp; branches; next ; commitid WSrDtL5nYAUyiyBx; 1.1.1.2.4.1 date 2014.05.30.18.14.40; author tls; state dead; branches; next 1.1.1.2.4.2; commitid jTnpym9Qu0o4R1Nx; 1.1.1.2.4.2 date 2014.08.19.23.47.26; author tls; state Exp; branches; next ; commitid jTnpym9Qu0o4R1Nx; 1.1.1.3.2.1 date 2017.03.20.06.52.36; author pgoyette; state Exp; branches; next ; commitid jjw7cAwgyKq7RfKz; 1.1.1.5.4.1 date 2020.04.13.07.46.31; author martin; state dead; branches; next ; commitid X01YhRUPVUDaec4C; desc @@ 1.1 log @Initial revision @ text @//== PseudoConstantAnalysis.cpp - Find Pseudoconstants in the AST-*- C++ -*-==// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file tracks the usage of variables in a Decl body to see if they are // never written to, implying that they constant. This is useful in static // analysis to see if a developer might have intended a variable to be const. // //===----------------------------------------------------------------------===// #include "clang/Analysis/Analyses/PseudoConstantAnalysis.h" #include "clang/AST/Decl.h" #include "clang/AST/Expr.h" #include "clang/AST/Stmt.h" #include "llvm/ADT/SmallPtrSet.h" #include using namespace clang; // The number of ValueDecls we want to keep track of by default (per-function) #define VARDECL_SET_SIZE 256 typedef llvm::SmallPtrSet VarDeclSet; PseudoConstantAnalysis::PseudoConstantAnalysis(const Stmt *DeclBody) : DeclBody(DeclBody), Analyzed(false) { NonConstantsImpl = new VarDeclSet; UsedVarsImpl = new VarDeclSet; } PseudoConstantAnalysis::~PseudoConstantAnalysis() { delete (VarDeclSet*)NonConstantsImpl; delete (VarDeclSet*)UsedVarsImpl; } // Returns true if the given ValueDecl is never written to in the given DeclBody bool PseudoConstantAnalysis::isPseudoConstant(const VarDecl *VD) { // Only local and static variables can be pseudoconstants if (!VD->hasLocalStorage() && !VD->isStaticLocal()) return false; if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; return !NonConstants->count(VD); } // Returns true if the variable was used (self assignments don't count) bool PseudoConstantAnalysis::wasReferenced(const VarDecl *VD) { if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; return UsedVars->count(VD); } // Returns a Decl from a (Block)DeclRefExpr (if any) const Decl *PseudoConstantAnalysis::getDecl(const Expr *E) { if (const DeclRefExpr *DR = dyn_cast(E)) return DR->getDecl(); else return 0; } void PseudoConstantAnalysis::RunAnalysis() { std::deque WorkList; VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; // Start with the top level statement of the function WorkList.push_back(DeclBody); while (!WorkList.empty()) { const Stmt *Head = WorkList.front(); WorkList.pop_front(); if (const Expr *Ex = dyn_cast(Head)) Head = Ex->IgnoreParenCasts(); switch (Head->getStmtClass()) { // Case 1: Assignment operators modifying VarDecls case Stmt::BinaryOperatorClass: { const BinaryOperator *BO = cast(Head); // Look for a Decl on the LHS const Decl *LHSDecl = getDecl(BO->getLHS()->IgnoreParenCasts()); if (!LHSDecl) break; // We found a binary operator with a DeclRefExpr on the LHS. We now check // for any of the assignment operators, implying that this Decl is being // written to. switch (BO->getOpcode()) { // Self-assignments don't count as use of a variable case BO_Assign: { // Look for a DeclRef on the RHS const Decl *RHSDecl = getDecl(BO->getRHS()->IgnoreParenCasts()); // If the Decls match, we have self-assignment if (LHSDecl == RHSDecl) // Do not visit the children continue; } case BO_AddAssign: case BO_SubAssign: case BO_MulAssign: case BO_DivAssign: case BO_AndAssign: case BO_OrAssign: case BO_XorAssign: case BO_ShlAssign: case BO_ShrAssign: { const VarDecl *VD = dyn_cast(LHSDecl); // The DeclRefExpr is being assigned to - mark it as non-constant if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 2: Pre/post increment/decrement and address of case Stmt::UnaryOperatorClass: { const UnaryOperator *UO = cast(Head); // Look for a DeclRef in the subexpression const Decl *D = getDecl(UO->getSubExpr()->IgnoreParenCasts()); if (!D) break; // We found a unary operator with a DeclRef as a subexpression. We now // check for any of the increment/decrement operators, as well as // addressOf. switch (UO->getOpcode()) { case UO_PostDec: case UO_PostInc: case UO_PreDec: case UO_PreInc: // The DeclRef is being changed - mark it as non-constant case UO_AddrOf: { // If we are taking the address of the DeclRefExpr, assume it is // non-constant. const VarDecl *VD = dyn_cast(D); if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 3: Reference Declarations case Stmt::DeclStmtClass: { const DeclStmt *DS = cast(Head); // Iterate over each decl and see if any of them contain reference decls for (DeclStmt::const_decl_iterator I = DS->decl_begin(), E = DS->decl_end(); I != E; ++I) { // We only care about VarDecls const VarDecl *VD = dyn_cast(*I); if (!VD) continue; // We found a VarDecl; make sure it is a reference type if (!VD->getType().getTypePtr()->isReferenceType()) continue; // Try to find a Decl in the initializer const Decl *D = getDecl(VD->getInit()->IgnoreParenCasts()); if (!D) break; // If the reference is to another var, add the var to the non-constant // list if (const VarDecl *RefVD = dyn_cast(D)) { NonConstants->insert(RefVD); continue; } } break; } // Case 4: Variable references case Stmt::DeclRefExprClass: { const DeclRefExpr *DR = cast(Head); if (const VarDecl *VD = dyn_cast(DR->getDecl())) { // Add the Decl to the used list UsedVars->insert(VD); continue; } break; } // Case 5: Block expressions case Stmt::BlockExprClass: { const BlockExpr *B = cast(Head); // Add the body of the block to the list WorkList.push_back(B->getBody()); continue; } default: break; } // switch (head->getStmtClass()) // Add all substatements to the worklist for (Stmt::const_child_range I = Head->children(); I; ++I) if (*I) WorkList.push_back(*I); } // while (!WorkList.empty()) } @ 1.1.1.1 log @Import Clang 3.4rc1 r195771. @ text @@ 1.1.1.1.2.1 log @Rebase. @ text @d73 1 a73 1 return nullptr; d174 2 a175 1 for (const auto *I : DS->decls()) { d177 1 a177 1 const VarDecl *VD = dyn_cast(I); @ 1.1.1.2 log @Import Clang 3.5svn r209886. @ text @d73 1 a73 1 return nullptr; d174 2 a175 1 for (const auto *I : DS->decls()) { d177 1 a177 1 const VarDecl *VD = dyn_cast(I); @ 1.1.1.3 log @Import Clang 3.8.0rc3 r261930. @ text @d223 3 a225 3 for (const Stmt *SubStmt : Head->children()) if (SubStmt) WorkList.push_back(SubStmt); @ 1.1.1.3.2.1 log @Sync with HEAD @ text @d25 3 a27 1 typedef llvm::SmallPtrSet VarDeclSet; @ 1.1.1.4 log @Import Clang pre-4.0.0 r291444. @ text @d25 3 a27 1 typedef llvm::SmallPtrSet VarDeclSet; @ 1.1.1.5 log @Import clang r309604 from branches/release_50 @ text @a111 1 LLVM_FALLTHROUGH; @ 1.1.1.5.4.1 log @Mostly merge changes from HEAD upto 20200411 @ text @@ 1.1.1.6 log @Mark old LLVM instance as dead. @ text @@ 1.1.1.2.4.1 log @file PseudoConstantAnalysis.cpp was added on branch tls-maxphys on 2014-08-19 23:47:26 +0000 @ text @d1 227 @ 1.1.1.2.4.2 log @Rebase to HEAD as of a few days ago. @ text @a0 227 //== PseudoConstantAnalysis.cpp - Find Pseudoconstants in the AST-*- C++ -*-==// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file tracks the usage of variables in a Decl body to see if they are // never written to, implying that they constant. This is useful in static // analysis to see if a developer might have intended a variable to be const. // //===----------------------------------------------------------------------===// #include "clang/Analysis/Analyses/PseudoConstantAnalysis.h" #include "clang/AST/Decl.h" #include "clang/AST/Expr.h" #include "clang/AST/Stmt.h" #include "llvm/ADT/SmallPtrSet.h" #include using namespace clang; // The number of ValueDecls we want to keep track of by default (per-function) #define VARDECL_SET_SIZE 256 typedef llvm::SmallPtrSet VarDeclSet; PseudoConstantAnalysis::PseudoConstantAnalysis(const Stmt *DeclBody) : DeclBody(DeclBody), Analyzed(false) { NonConstantsImpl = new VarDeclSet; UsedVarsImpl = new VarDeclSet; } PseudoConstantAnalysis::~PseudoConstantAnalysis() { delete (VarDeclSet*)NonConstantsImpl; delete (VarDeclSet*)UsedVarsImpl; } // Returns true if the given ValueDecl is never written to in the given DeclBody bool PseudoConstantAnalysis::isPseudoConstant(const VarDecl *VD) { // Only local and static variables can be pseudoconstants if (!VD->hasLocalStorage() && !VD->isStaticLocal()) return false; if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; return !NonConstants->count(VD); } // Returns true if the variable was used (self assignments don't count) bool PseudoConstantAnalysis::wasReferenced(const VarDecl *VD) { if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; return UsedVars->count(VD); } // Returns a Decl from a (Block)DeclRefExpr (if any) const Decl *PseudoConstantAnalysis::getDecl(const Expr *E) { if (const DeclRefExpr *DR = dyn_cast(E)) return DR->getDecl(); else return nullptr; } void PseudoConstantAnalysis::RunAnalysis() { std::deque WorkList; VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; // Start with the top level statement of the function WorkList.push_back(DeclBody); while (!WorkList.empty()) { const Stmt *Head = WorkList.front(); WorkList.pop_front(); if (const Expr *Ex = dyn_cast(Head)) Head = Ex->IgnoreParenCasts(); switch (Head->getStmtClass()) { // Case 1: Assignment operators modifying VarDecls case Stmt::BinaryOperatorClass: { const BinaryOperator *BO = cast(Head); // Look for a Decl on the LHS const Decl *LHSDecl = getDecl(BO->getLHS()->IgnoreParenCasts()); if (!LHSDecl) break; // We found a binary operator with a DeclRefExpr on the LHS. We now check // for any of the assignment operators, implying that this Decl is being // written to. switch (BO->getOpcode()) { // Self-assignments don't count as use of a variable case BO_Assign: { // Look for a DeclRef on the RHS const Decl *RHSDecl = getDecl(BO->getRHS()->IgnoreParenCasts()); // If the Decls match, we have self-assignment if (LHSDecl == RHSDecl) // Do not visit the children continue; } case BO_AddAssign: case BO_SubAssign: case BO_MulAssign: case BO_DivAssign: case BO_AndAssign: case BO_OrAssign: case BO_XorAssign: case BO_ShlAssign: case BO_ShrAssign: { const VarDecl *VD = dyn_cast(LHSDecl); // The DeclRefExpr is being assigned to - mark it as non-constant if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 2: Pre/post increment/decrement and address of case Stmt::UnaryOperatorClass: { const UnaryOperator *UO = cast(Head); // Look for a DeclRef in the subexpression const Decl *D = getDecl(UO->getSubExpr()->IgnoreParenCasts()); if (!D) break; // We found a unary operator with a DeclRef as a subexpression. We now // check for any of the increment/decrement operators, as well as // addressOf. switch (UO->getOpcode()) { case UO_PostDec: case UO_PostInc: case UO_PreDec: case UO_PreInc: // The DeclRef is being changed - mark it as non-constant case UO_AddrOf: { // If we are taking the address of the DeclRefExpr, assume it is // non-constant. const VarDecl *VD = dyn_cast(D); if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 3: Reference Declarations case Stmt::DeclStmtClass: { const DeclStmt *DS = cast(Head); // Iterate over each decl and see if any of them contain reference decls for (const auto *I : DS->decls()) { // We only care about VarDecls const VarDecl *VD = dyn_cast(I); if (!VD) continue; // We found a VarDecl; make sure it is a reference type if (!VD->getType().getTypePtr()->isReferenceType()) continue; // Try to find a Decl in the initializer const Decl *D = getDecl(VD->getInit()->IgnoreParenCasts()); if (!D) break; // If the reference is to another var, add the var to the non-constant // list if (const VarDecl *RefVD = dyn_cast(D)) { NonConstants->insert(RefVD); continue; } } break; } // Case 4: Variable references case Stmt::DeclRefExprClass: { const DeclRefExpr *DR = cast(Head); if (const VarDecl *VD = dyn_cast(DR->getDecl())) { // Add the Decl to the used list UsedVars->insert(VD); continue; } break; } // Case 5: Block expressions case Stmt::BlockExprClass: { const BlockExpr *B = cast(Head); // Add the body of the block to the list WorkList.push_back(B->getBody()); continue; } default: break; } // switch (head->getStmtClass()) // Add all substatements to the worklist for (Stmt::const_child_range I = Head->children(); I; ++I) if (*I) WorkList.push_back(*I); } // while (!WorkList.empty()) } @ 1.1.1.1.4.1 log @file PseudoConstantAnalysis.cpp was added on branch yamt-pagecache on 2014-05-22 16:18:26 +0000 @ text @d1 228 @ 1.1.1.1.4.2 log @sync with head. for a reference, the tree before this commit was tagged as yamt-pagecache-tag8. this commit was splitted into small chunks to avoid a limitation of cvs. ("Protocol error: too many arguments") @ text @a0 228 //== PseudoConstantAnalysis.cpp - Find Pseudoconstants in the AST-*- C++ -*-==// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file tracks the usage of variables in a Decl body to see if they are // never written to, implying that they constant. This is useful in static // analysis to see if a developer might have intended a variable to be const. // //===----------------------------------------------------------------------===// #include "clang/Analysis/Analyses/PseudoConstantAnalysis.h" #include "clang/AST/Decl.h" #include "clang/AST/Expr.h" #include "clang/AST/Stmt.h" #include "llvm/ADT/SmallPtrSet.h" #include using namespace clang; // The number of ValueDecls we want to keep track of by default (per-function) #define VARDECL_SET_SIZE 256 typedef llvm::SmallPtrSet VarDeclSet; PseudoConstantAnalysis::PseudoConstantAnalysis(const Stmt *DeclBody) : DeclBody(DeclBody), Analyzed(false) { NonConstantsImpl = new VarDeclSet; UsedVarsImpl = new VarDeclSet; } PseudoConstantAnalysis::~PseudoConstantAnalysis() { delete (VarDeclSet*)NonConstantsImpl; delete (VarDeclSet*)UsedVarsImpl; } // Returns true if the given ValueDecl is never written to in the given DeclBody bool PseudoConstantAnalysis::isPseudoConstant(const VarDecl *VD) { // Only local and static variables can be pseudoconstants if (!VD->hasLocalStorage() && !VD->isStaticLocal()) return false; if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; return !NonConstants->count(VD); } // Returns true if the variable was used (self assignments don't count) bool PseudoConstantAnalysis::wasReferenced(const VarDecl *VD) { if (!Analyzed) { RunAnalysis(); Analyzed = true; } VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; return UsedVars->count(VD); } // Returns a Decl from a (Block)DeclRefExpr (if any) const Decl *PseudoConstantAnalysis::getDecl(const Expr *E) { if (const DeclRefExpr *DR = dyn_cast(E)) return DR->getDecl(); else return 0; } void PseudoConstantAnalysis::RunAnalysis() { std::deque WorkList; VarDeclSet *NonConstants = (VarDeclSet*)NonConstantsImpl; VarDeclSet *UsedVars = (VarDeclSet*)UsedVarsImpl; // Start with the top level statement of the function WorkList.push_back(DeclBody); while (!WorkList.empty()) { const Stmt *Head = WorkList.front(); WorkList.pop_front(); if (const Expr *Ex = dyn_cast(Head)) Head = Ex->IgnoreParenCasts(); switch (Head->getStmtClass()) { // Case 1: Assignment operators modifying VarDecls case Stmt::BinaryOperatorClass: { const BinaryOperator *BO = cast(Head); // Look for a Decl on the LHS const Decl *LHSDecl = getDecl(BO->getLHS()->IgnoreParenCasts()); if (!LHSDecl) break; // We found a binary operator with a DeclRefExpr on the LHS. We now check // for any of the assignment operators, implying that this Decl is being // written to. switch (BO->getOpcode()) { // Self-assignments don't count as use of a variable case BO_Assign: { // Look for a DeclRef on the RHS const Decl *RHSDecl = getDecl(BO->getRHS()->IgnoreParenCasts()); // If the Decls match, we have self-assignment if (LHSDecl == RHSDecl) // Do not visit the children continue; } case BO_AddAssign: case BO_SubAssign: case BO_MulAssign: case BO_DivAssign: case BO_AndAssign: case BO_OrAssign: case BO_XorAssign: case BO_ShlAssign: case BO_ShrAssign: { const VarDecl *VD = dyn_cast(LHSDecl); // The DeclRefExpr is being assigned to - mark it as non-constant if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 2: Pre/post increment/decrement and address of case Stmt::UnaryOperatorClass: { const UnaryOperator *UO = cast(Head); // Look for a DeclRef in the subexpression const Decl *D = getDecl(UO->getSubExpr()->IgnoreParenCasts()); if (!D) break; // We found a unary operator with a DeclRef as a subexpression. We now // check for any of the increment/decrement operators, as well as // addressOf. switch (UO->getOpcode()) { case UO_PostDec: case UO_PostInc: case UO_PreDec: case UO_PreInc: // The DeclRef is being changed - mark it as non-constant case UO_AddrOf: { // If we are taking the address of the DeclRefExpr, assume it is // non-constant. const VarDecl *VD = dyn_cast(D); if (VD) NonConstants->insert(VD); break; } default: break; } break; } // Case 3: Reference Declarations case Stmt::DeclStmtClass: { const DeclStmt *DS = cast(Head); // Iterate over each decl and see if any of them contain reference decls for (DeclStmt::const_decl_iterator I = DS->decl_begin(), E = DS->decl_end(); I != E; ++I) { // We only care about VarDecls const VarDecl *VD = dyn_cast(*I); if (!VD) continue; // We found a VarDecl; make sure it is a reference type if (!VD->getType().getTypePtr()->isReferenceType()) continue; // Try to find a Decl in the initializer const Decl *D = getDecl(VD->getInit()->IgnoreParenCasts()); if (!D) break; // If the reference is to another var, add the var to the non-constant // list if (const VarDecl *RefVD = dyn_cast(D)) { NonConstants->insert(RefVD); continue; } } break; } // Case 4: Variable references case Stmt::DeclRefExprClass: { const DeclRefExpr *DR = cast(Head); if (const VarDecl *VD = dyn_cast(DR->getDecl())) { // Add the Decl to the used list UsedVars->insert(VD); continue; } break; } // Case 5: Block expressions case Stmt::BlockExprClass: { const BlockExpr *B = cast(Head); // Add the body of the block to the list WorkList.push_back(B->getBody()); continue; } default: break; } // switch (head->getStmtClass()) // Add all substatements to the worklist for (Stmt::const_child_range I = Head->children(); I; ++I) if (*I) WorkList.push_back(*I); } // while (!WorkList.empty()) } @