llvm-project/clang-tools-extra/clang-modernize/LoopConvert/LoopMatchers.cpp

347 lines
12 KiB
C++

//===-- LoopConvert/LoopMatchers.cpp - Matchers for for loops -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file contains definitions of the matchers for use in migrating
/// C++ for loops.
///
//===----------------------------------------------------------------------===//
#include "LoopMatchers.h"
using namespace clang::ast_matchers;
using namespace clang;
const char LoopName[] = "forLoop";
const char ConditionBoundName[] = "conditionBound";
const char ConditionVarName[] = "conditionVar";
const char IncrementVarName[] = "incrementVar";
const char InitVarName[] = "initVar";
const char BeginCallName[] = "beginCall";
const char EndCallName[] = "endCall";
const char ConditionEndVarName[] = "conditionEndVar";
const char EndVarName[] = "endVar";
const char DerefByValueResultName[] = "derefByValueResult";
const char DerefByRefResultName[] = "derefByRefResult";
// shared matchers
static const TypeMatcher AnyType = anything();
static const StatementMatcher IntegerComparisonMatcher =
expr(ignoringParenImpCasts(declRefExpr(to(
varDecl(hasType(isInteger())).bind(ConditionVarName)))));
static const DeclarationMatcher InitToZeroMatcher =
varDecl(hasInitializer(ignoringParenImpCasts(
integerLiteral(equals(0))))).bind(InitVarName);
static const StatementMatcher IncrementVarMatcher =
declRefExpr(to(
varDecl(hasType(isInteger())).bind(IncrementVarName)));
// FIXME: How best to document complicated matcher expressions? They're fairly
// self-documenting...but there may be some unintuitive parts.
/// \brief The matcher for loops over arrays.
///
/// In this general example, assuming 'j' and 'k' are of integral type:
/// \code
/// for (int i = 0; j < 3 + 2; ++k) { ... }
/// \endcode
/// The following string identifiers are bound to these parts of the AST:
/// ConditionVarName: 'j' (as a VarDecl)
/// ConditionBoundName: '3 + 2' (as an Expr)
/// InitVarName: 'i' (as a VarDecl)
/// IncrementVarName: 'k' (as a VarDecl)
/// LoopName: The entire for loop (as a ForStmt)
///
/// Client code will need to make sure that:
/// - The three index variables identified by the matcher are the same
/// VarDecl.
/// - The index variable is only used as an array index.
/// - All arrays indexed by the loop are the same.
StatementMatcher makeArrayLoopMatcher() {
StatementMatcher ArrayBoundMatcher =
expr(hasType(isInteger())).bind(ConditionBoundName);
return forStmt(
hasLoopInit(declStmt(hasSingleDecl(InitToZeroMatcher))),
hasCondition(anyOf(binaryOperator(hasOperatorName("<"),
hasLHS(IntegerComparisonMatcher),
hasRHS(ArrayBoundMatcher)),
binaryOperator(hasOperatorName(">"),
hasLHS(ArrayBoundMatcher),
hasRHS(IntegerComparisonMatcher)))),
hasIncrement(unaryOperator(hasOperatorName("++"),
hasUnaryOperand(IncrementVarMatcher))))
.bind(LoopName);
}
/// \brief The matcher used for iterator-based for loops.
///
/// This matcher is more flexible than array-based loops. It will match
/// catch loops of the following textual forms (regardless of whether the
/// iterator type is actually a pointer type or a class type):
///
/// Assuming f, g, and h are of type containerType::iterator,
/// \code
/// for (containerType::iterator it = container.begin(),
/// e = createIterator(); f != g; ++h) { ... }
/// for (containerType::iterator it = container.begin();
/// f != anotherContainer.end(); ++h) { ... }
/// \endcode
/// The following string identifiers are bound to the parts of the AST:
/// InitVarName: 'it' (as a VarDecl)
/// ConditionVarName: 'f' (as a VarDecl)
/// LoopName: The entire for loop (as a ForStmt)
/// In the first example only:
/// EndVarName: 'e' (as a VarDecl)
/// ConditionEndVarName: 'g' (as a VarDecl)
/// In the second example only:
/// EndCallName: 'container.end()' (as a CXXMemberCallExpr)
///
/// Client code will need to make sure that:
/// - The iterator variables 'it', 'f', and 'h' are the same
/// - The two containers on which 'begin' and 'end' are called are the same
/// - If the end iterator variable 'g' is defined, it is the same as 'f'
StatementMatcher makeIteratorLoopMatcher() {
StatementMatcher BeginCallMatcher =
memberCallExpr(
argumentCountIs(0),
callee(
methodDecl(hasName("begin"))
)
).bind(BeginCallName);
DeclarationMatcher InitDeclMatcher =
varDecl(
hasInitializer(
anyOf(
ignoringParenImpCasts(BeginCallMatcher),
materializeTemporaryExpr(ignoringParenImpCasts(BeginCallMatcher)),
hasDescendant(BeginCallMatcher)
)
)
).bind(InitVarName);
DeclarationMatcher EndDeclMatcher =
varDecl(hasInitializer(anything())).bind(EndVarName);
StatementMatcher EndCallMatcher =
memberCallExpr(argumentCountIs(0), callee(methodDecl(hasName("end"))));
StatementMatcher IteratorBoundMatcher =
expr(anyOf(ignoringParenImpCasts(declRefExpr(to(
varDecl().bind(ConditionEndVarName)))),
ignoringParenImpCasts(
expr(EndCallMatcher).bind(EndCallName)),
materializeTemporaryExpr(ignoringParenImpCasts(
expr(EndCallMatcher).bind(EndCallName)))));
StatementMatcher IteratorComparisonMatcher =
expr(ignoringParenImpCasts(declRefExpr(to(
varDecl().bind(ConditionVarName)))));
StatementMatcher OverloadedNEQMatcher = operatorCallExpr(
hasOverloadedOperatorName("!="),
argumentCountIs(2),
hasArgument(0, IteratorComparisonMatcher),
hasArgument(1, IteratorBoundMatcher));
// This matcher tests that a declaration is a CXXRecordDecl that has an
// overloaded operator*(). If the operator*() returns by value instead of by
// reference then the return type is tagged with DerefByValueResultName.
internal::Matcher<VarDecl> TestDerefReturnsByValue =
hasType(
recordDecl(
hasMethod(
allOf(
hasOverloadedOperatorName("*"),
anyOf(
// Tag the return type if it's by value.
returns(
qualType(
unless(hasCanonicalType(referenceType()))
).bind(DerefByValueResultName)
),
returns(
// Skip loops where the iterator's operator* returns an
// rvalue reference. This is just weird.
qualType(
unless(
hasCanonicalType(rValueReferenceType())
)
).bind(DerefByRefResultName)
)
)
)
)
)
);
return
forStmt(
hasLoopInit(anyOf(
declStmt(
declCountIs(2),
containsDeclaration(0, InitDeclMatcher),
containsDeclaration(1, EndDeclMatcher)
),
declStmt(hasSingleDecl(InitDeclMatcher))
)),
hasCondition(anyOf(
binaryOperator(
hasOperatorName("!="),
hasLHS(IteratorComparisonMatcher),
hasRHS(IteratorBoundMatcher)
),
binaryOperator(
hasOperatorName("!="),
hasLHS(IteratorBoundMatcher),
hasRHS(IteratorComparisonMatcher)
),
OverloadedNEQMatcher
)),
hasIncrement(anyOf(
unaryOperator(
hasOperatorName("++"),
hasUnaryOperand(
declRefExpr(to(
varDecl(hasType(pointsTo(AnyType))).bind(IncrementVarName)
))
)
),
operatorCallExpr(
hasOverloadedOperatorName("++"),
hasArgument(0,
declRefExpr(to(
varDecl(TestDerefReturnsByValue).bind(IncrementVarName)
))
)
)
))
).bind(LoopName);
}
/// \brief The matcher used for array-like containers (pseudoarrays).
///
/// This matcher is more flexible than array-based loops. It will match
/// loops of the following textual forms (regardless of whether the
/// iterator type is actually a pointer type or a class type):
///
/// Assuming f, g, and h are of type containerType::iterator,
/// \code
/// for (int i = 0, j = container.size(); f < g; ++h) { ... }
/// for (int i = 0; f < container.size(); ++h) { ... }
/// \endcode
/// The following string identifiers are bound to the parts of the AST:
/// InitVarName: 'i' (as a VarDecl)
/// ConditionVarName: 'f' (as a VarDecl)
/// LoopName: The entire for loop (as a ForStmt)
/// In the first example only:
/// EndVarName: 'j' (as a VarDecl)
/// ConditionEndVarName: 'g' (as a VarDecl)
/// In the second example only:
/// EndCallName: 'container.size()' (as a CXXMemberCallExpr)
///
/// Client code will need to make sure that:
/// - The index variables 'i', 'f', and 'h' are the same
/// - The containers on which 'size()' is called is the container indexed
/// - The index variable is only used in overloaded operator[] or
/// container.at()
/// - If the end iterator variable 'g' is defined, it is the same as 'j'
/// - The container's iterators would not be invalidated during the loop
StatementMatcher makePseudoArrayLoopMatcher() {
// Test that the incoming type has a record declaration that has methods
// called 'begin' and 'end'. If the incoming type is const, then make sure
// these methods are also marked const.
//
// FIXME: To be completely thorough this matcher should also ensure the
// return type of begin/end is an iterator that dereferences to the same as
// what operator[] or at() returns. Such a test isn't likely to fail except
// for pathological cases.
//
// FIXME: Also, a record doesn't necessarily need begin() and end(). Free
// functions called begin() and end() taking the container as an argument
// are also allowed.
TypeMatcher RecordWithBeginEnd =
qualType(anyOf(
qualType(
isConstQualified(),
hasDeclaration(
recordDecl(
hasMethod(
methodDecl(
hasName("begin"),
isConst()
)
),
hasMethod(
methodDecl(
hasName("end"),
isConst()
)
)
)
) // hasDeclaration
), // qualType
qualType(
unless(isConstQualified()),
hasDeclaration(
recordDecl(
hasMethod(hasName("begin")),
hasMethod(hasName("end"))
)
)
) // qualType
)
);
StatementMatcher SizeCallMatcher =
memberCallExpr(argumentCountIs(0),
callee(methodDecl(anyOf(hasName("size"),
hasName("length")))),
on(anyOf(hasType(pointsTo(RecordWithBeginEnd)),
hasType(RecordWithBeginEnd))));
StatementMatcher EndInitMatcher =
expr(anyOf(
ignoringParenImpCasts(expr(SizeCallMatcher).bind(EndCallName)),
explicitCastExpr(hasSourceExpression(ignoringParenImpCasts(
expr(SizeCallMatcher).bind(EndCallName))))));
DeclarationMatcher EndDeclMatcher =
varDecl(hasInitializer(EndInitMatcher)).bind(EndVarName);
StatementMatcher IndexBoundMatcher =
expr(anyOf(
ignoringParenImpCasts(declRefExpr(to(
varDecl(hasType(isInteger())).bind(ConditionEndVarName)))),
EndInitMatcher));
return forStmt(
hasLoopInit(anyOf(
declStmt(declCountIs(2),
containsDeclaration(0, InitToZeroMatcher),
containsDeclaration(1, EndDeclMatcher)),
declStmt(hasSingleDecl(InitToZeroMatcher)))),
hasCondition(anyOf(
binaryOperator(hasOperatorName("<"),
hasLHS(IntegerComparisonMatcher),
hasRHS(IndexBoundMatcher)),
binaryOperator(hasOperatorName(">"),
hasLHS(IndexBoundMatcher),
hasRHS(IntegerComparisonMatcher)))),
hasIncrement(unaryOperator(
hasOperatorName("++"),
hasUnaryOperand(IncrementVarMatcher))))
.bind(LoopName);
}