This is an archive of the discontinued LLVM Phabricator instance.

	//== PseudoConstantAnalysis.h - Find Pseudo-constants 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.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_PSEUDOCONSTANTANALYSIS_H
	#define LLVM_CLANG_ANALYSIS_ANALYSES_PSEUDOCONSTANTANALYSIS_H

	#include "clang/AST/Stmt.h"

	namespace clang {

	class PseudoConstantAnalysis {
	public:
	PseudoConstantAnalysis(const Stmt *DeclBody);
	~PseudoConstantAnalysis();

	bool isPseudoConstant(const VarDecl *VD);
	bool wasReferenced(const VarDecl *VD);

	private:
	void RunAnalysis();
	inline static const Decl getDecl(const Expr E);

	// for storing the result of analyzed ValueDecls
	void *NonConstantsImpl;
	void *UsedVarsImpl;

	const Stmt *DeclBody;
	bool Analyzed;
	};

	}

	#endif

cfe/trunk/include/clang/Analysis/AnalysisDeclContext.h

Show All 34 Lines
class BlockDecl;		class BlockDecl;
class BlockInvocationContext;		class BlockInvocationContext;
class CFGReverseBlockReachabilityAnalysis;		class CFGReverseBlockReachabilityAnalysis;
class CFGStmtMap;		class CFGStmtMap;
class ImplicitParamDecl;		class ImplicitParamDecl;
class LocationContext;		class LocationContext;
class LocationContextManager;		class LocationContextManager;
class ParentMap;		class ParentMap;
class PseudoConstantAnalysis;
class StackFrameContext;		class StackFrameContext;
class Stmt;		class Stmt;
class VarDecl;		class VarDecl;

/// The base class of a hierarchy of objects representing analyses tied		/// The base class of a hierarchy of objects representing analyses tied
/// to AnalysisDeclContext.		/// to AnalysisDeclContext.
class ManagedAnalysis {		class ManagedAnalysis {
protected:		protected:
Show All 27 Lines	class AnalysisDeclContext {
std::unique_ptr<CFGStmtMap> cfgStmtMap;		std::unique_ptr<CFGStmtMap> cfgStmtMap;

CFG::BuildOptions cfgBuildOptions;		CFG::BuildOptions cfgBuildOptions;
CFG::BuildOptions::ForcedBlkExprs *forcedBlkExprs = nullptr;		CFG::BuildOptions::ForcedBlkExprs *forcedBlkExprs = nullptr;

bool builtCFG = false;		bool builtCFG = false;
bool builtCompleteCFG = false;		bool builtCompleteCFG = false;
std::unique_ptr<ParentMap> PM;		std::unique_ptr<ParentMap> PM;
std::unique_ptr<PseudoConstantAnalysis> PCA;
std::unique_ptr<CFGReverseBlockReachabilityAnalysis> CFA;		std::unique_ptr<CFGReverseBlockReachabilityAnalysis> CFA;

llvm::BumpPtrAllocator A;		llvm::BumpPtrAllocator A;

llvm::DenseMap<const BlockDecl ,void > *ReferencedBlockVars = nullptr;		llvm::DenseMap<const BlockDecl ,void > *ReferencedBlockVars = nullptr;

void *ManagedAnalyses = nullptr;		void *ManagedAnalyses = nullptr;

▲ Show 20 Lines • Show All 74 Lines • ▼ Show 20 Lines	public:
void dumpCFG(bool ShowColors);		void dumpCFG(bool ShowColors);

/// Returns true if we have built a CFG for this analysis context.		/// Returns true if we have built a CFG for this analysis context.
/// Note that this doesn't correspond to whether or not a valid CFG exists, it		/// Note that this doesn't correspond to whether or not a valid CFG exists, it
/// corresponds to whether we attempted to build one.		/// corresponds to whether we attempted to build one.
bool isCFGBuilt() const { return builtCFG; }		bool isCFGBuilt() const { return builtCFG; }

ParentMap &getParentMap();		ParentMap &getParentMap();
PseudoConstantAnalysis *getPseudoConstantAnalysis();

using referenced_decls_iterator = const VarDecl * const *;		using referenced_decls_iterator = const VarDecl * const *;

llvm::iterator_range<referenced_decls_iterator>		llvm::iterator_range<referenced_decls_iterator>
getReferencedBlockVars(const BlockDecl *BD);		getReferencedBlockVars(const BlockDecl *BD);

/// Return the ImplicitParamDecl* associated with 'self' if this		/// Return the ImplicitParamDecl* associated with 'self' if this
/// AnalysisDeclContext wraps an ObjCMethodDecl. Returns NULL otherwise.		/// AnalysisDeclContext wraps an ObjCMethodDecl. Returns NULL otherwise.
▲ Show 20 Lines • Show All 324 Lines • Show Last 20 Lines

cfe/trunk/lib/Analysis/AnalysisDeclContext.cpp

Show All 21 Lines
#include "clang/AST/Expr.h"		#include "clang/AST/Expr.h"
#include "clang/AST/LambdaCapture.h"		#include "clang/AST/LambdaCapture.h"
#include "clang/AST/ParentMap.h"		#include "clang/AST/ParentMap.h"
#include "clang/AST/PrettyPrinter.h"		#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/Stmt.h"		#include "clang/AST/Stmt.h"
#include "clang/AST/StmtCXX.h"		#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtVisitor.h"		#include "clang/AST/StmtVisitor.h"
#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"		#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
#include "clang/Analysis/Analyses/PseudoConstantAnalysis.h"
#include "clang/Analysis/BodyFarm.h"		#include "clang/Analysis/BodyFarm.h"
#include "clang/Analysis/CFG.h"		#include "clang/Analysis/CFG.h"
#include "clang/Analysis/CFGStmtMap.h"		#include "clang/Analysis/CFGStmtMap.h"
#include "clang/Analysis/Support/BumpVector.h"		#include "clang/Analysis/Support/BumpVector.h"
#include "clang/Basic/LLVM.h"		#include "clang/Basic/LLVM.h"
#include "clang/Basic/SourceLocation.h"		#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"		#include "clang/Basic/SourceManager.h"
#include "llvm/ADT/DenseMap.h"		#include "llvm/ADT/DenseMap.h"
▲ Show 20 Lines • Show All 248 Lines • ▼ Show 20 Lines	if (!PM) {
if (builtCFG)		if (builtCFG)
addParentsForSyntheticStmts(getCFG(), *PM);		addParentsForSyntheticStmts(getCFG(), *PM);
if (builtCompleteCFG)		if (builtCompleteCFG)
addParentsForSyntheticStmts(getUnoptimizedCFG(), *PM);		addParentsForSyntheticStmts(getUnoptimizedCFG(), *PM);
}		}
return *PM;		return *PM;
}		}

PseudoConstantAnalysis *AnalysisDeclContext::getPseudoConstantAnalysis() {
if (!PCA)
PCA.reset(new PseudoConstantAnalysis(getBody()));
return PCA.get();
}

AnalysisDeclContext AnalysisDeclContextManager::getContext(const Decl D) {		AnalysisDeclContext AnalysisDeclContextManager::getContext(const Decl D) {
if (const auto *FD = dyn_cast<FunctionDecl>(D)) {		if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
// Calling 'hasBody' replaces 'FD' in place with the FunctionDecl		// Calling 'hasBody' replaces 'FD' in place with the FunctionDecl
// that has the body.		// that has the body.
FD->hasBody(FD);		FD->hasBody(FD);
D = FD;		D = FD;
}		}

▲ Show 20 Lines • Show All 344 Lines • Show Last 20 Lines

cfe/trunk/lib/Analysis/CMakeLists.txt

Show All 17 Lines	add_clang_library(clangAnalysis
ExprMutationAnalyzer.cpp		ExprMutationAnalyzer.cpp
FormatString.cpp		FormatString.cpp
LiveVariables.cpp		LiveVariables.cpp
OSLog.cpp		OSLog.cpp
ObjCNoReturn.cpp		ObjCNoReturn.cpp
PostOrderCFGView.cpp		PostOrderCFGView.cpp
PrintfFormatString.cpp		PrintfFormatString.cpp
ProgramPoint.cpp		ProgramPoint.cpp
PseudoConstantAnalysis.cpp
ReachableCode.cpp		ReachableCode.cpp
ScanfFormatString.cpp		ScanfFormatString.cpp
ThreadSafety.cpp		ThreadSafety.cpp
ThreadSafetyCommon.cpp		ThreadSafetyCommon.cpp
ThreadSafetyLogical.cpp		ThreadSafetyLogical.cpp
ThreadSafetyTIL.cpp		ThreadSafetyTIL.cpp
UninitializedValues.cpp		UninitializedValues.cpp

LINK_LIBS		LINK_LIBS
clangAST		clangAST
clangASTMatchers		clangASTMatchers
clangBasic		clangBasic
clangLex		clangLex
)		)

cfe/trunk/lib/Analysis/PseudoConstantAnalysis.cpp

	//== 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 <deque>

	using namespace clang;

	typedef llvm::SmallPtrSet<const VarDecl*, 32> 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<DeclRefExpr>(E))
	return DR->getDecl();
	else
	return nullptr;
	}

	void PseudoConstantAnalysis::RunAnalysis() {
	std::deque<const Stmt *> 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<Expr>(Head))
	Head = Ex->IgnoreParenCasts();

	switch (Head->getStmtClass()) {
	// Case 1: Assignment operators modifying VarDecls
	case Stmt::BinaryOperatorClass: {
	const BinaryOperator *BO = cast<BinaryOperator>(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;

	LLVM_FALLTHROUGH;
	}
	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<VarDecl>(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<UnaryOperator>(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<VarDecl>(D);
	if (VD)
	NonConstants->insert(VD);
	break;
	}

	default:
	break;
	}
	break;
	}

	// Case 3: Reference Declarations
	case Stmt::DeclStmtClass: {
	const DeclStmt *DS = cast<DeclStmt>(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<VarDecl>(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<VarDecl>(D)) {
	NonConstants->insert(RefVD);
	continue;
	}
	}
	break;
	}

	// Case 4: Variable references
	case Stmt::DeclRefExprClass: {
	const DeclRefExpr *DR = cast<DeclRefExpr>(Head);
	if (const VarDecl *VD = dyn_cast<VarDecl>(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<BlockExpr>(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 (const Stmt *SubStmt : Head->children())
	if (SubStmt)
	WorkList.push_back(SubStmt);
	} // while (!WorkList.empty())
	}

This is an archive of the discontinued LLVM Phabricator instance.

[analyzer] Remove PseudoConstantAnalysisClosedPublic

Details

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Revision Contents

Diff 165531

cfe/trunk/include/clang/Analysis/Analyses/PseudoConstantAnalysis.h

cfe/trunk/include/clang/Analysis/AnalysisDeclContext.h

cfe/trunk/lib/Analysis/AnalysisDeclContext.cpp

cfe/trunk/lib/Analysis/CMakeLists.txt

cfe/trunk/lib/Analysis/PseudoConstantAnalysis.cpp

[analyzer] Remove PseudoConstantAnalysis
ClosedPublic