mirror of
https://github.com/capstone-engine/llvm-capstone.git
synced 2024-12-05 04:38:37 +00:00
8ae1203992
llvm-svn: 208163
254 lines
7.1 KiB
C++
254 lines
7.1 KiB
C++
//===--- TransEmptyStatements.cpp - Transformations to ARC mode -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// removeEmptyStatementsAndDealloc:
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//
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// Removes empty statements that are leftovers from previous transformations.
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// e.g for
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//
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// [x retain];
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//
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// removeRetainReleaseDealloc will leave an empty ";" that removeEmptyStatements
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// will remove.
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//
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//===----------------------------------------------------------------------===//
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#include "Transforms.h"
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#include "Internals.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Basic/SourceManager.h"
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using namespace clang;
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using namespace arcmt;
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using namespace trans;
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static bool isEmptyARCMTMacroStatement(NullStmt *S,
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std::vector<SourceLocation> &MacroLocs,
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ASTContext &Ctx) {
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if (!S->hasLeadingEmptyMacro())
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return false;
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SourceLocation SemiLoc = S->getSemiLoc();
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if (SemiLoc.isInvalid() || SemiLoc.isMacroID())
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return false;
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if (MacroLocs.empty())
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return false;
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SourceManager &SM = Ctx.getSourceManager();
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std::vector<SourceLocation>::iterator
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I = std::upper_bound(MacroLocs.begin(), MacroLocs.end(), SemiLoc,
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BeforeThanCompare<SourceLocation>(SM));
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--I;
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SourceLocation
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AfterMacroLoc = I->getLocWithOffset(getARCMTMacroName().size());
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assert(AfterMacroLoc.isFileID());
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if (AfterMacroLoc == SemiLoc)
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return true;
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int RelOffs = 0;
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if (!SM.isInSameSLocAddrSpace(AfterMacroLoc, SemiLoc, &RelOffs))
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return false;
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if (RelOffs < 0)
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return false;
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// We make the reasonable assumption that a semicolon after 100 characters
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// means that it is not the next token after our macro. If this assumption
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// fails it is not critical, we will just fail to clear out, e.g., an empty
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// 'if'.
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if (RelOffs - getARCMTMacroName().size() > 100)
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return false;
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SourceLocation AfterMacroSemiLoc = findSemiAfterLocation(AfterMacroLoc, Ctx);
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return AfterMacroSemiLoc == SemiLoc;
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}
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namespace {
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/// \brief Returns true if the statement became empty due to previous
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/// transformations.
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class EmptyChecker : public StmtVisitor<EmptyChecker, bool> {
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ASTContext &Ctx;
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std::vector<SourceLocation> &MacroLocs;
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public:
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EmptyChecker(ASTContext &ctx, std::vector<SourceLocation> ¯oLocs)
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: Ctx(ctx), MacroLocs(macroLocs) { }
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bool VisitNullStmt(NullStmt *S) {
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return isEmptyARCMTMacroStatement(S, MacroLocs, Ctx);
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}
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bool VisitCompoundStmt(CompoundStmt *S) {
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if (S->body_empty())
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return false; // was already empty, not because of transformations.
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for (auto *I : S->body())
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if (!Visit(I))
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return false;
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return true;
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}
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bool VisitIfStmt(IfStmt *S) {
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if (S->getConditionVariable())
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return false;
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Expr *condE = S->getCond();
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if (!condE)
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return false;
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if (hasSideEffects(condE, Ctx))
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return false;
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if (!S->getThen() || !Visit(S->getThen()))
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return false;
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if (S->getElse() && !Visit(S->getElse()))
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return false;
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return true;
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}
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bool VisitWhileStmt(WhileStmt *S) {
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if (S->getConditionVariable())
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return false;
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Expr *condE = S->getCond();
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if (!condE)
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return false;
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if (hasSideEffects(condE, Ctx))
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return false;
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if (!S->getBody())
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return false;
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return Visit(S->getBody());
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}
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bool VisitDoStmt(DoStmt *S) {
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Expr *condE = S->getCond();
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if (!condE)
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return false;
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if (hasSideEffects(condE, Ctx))
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return false;
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if (!S->getBody())
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return false;
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return Visit(S->getBody());
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}
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bool VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
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Expr *Exp = S->getCollection();
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if (!Exp)
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return false;
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if (hasSideEffects(Exp, Ctx))
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return false;
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if (!S->getBody())
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return false;
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return Visit(S->getBody());
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}
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bool VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
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if (!S->getSubStmt())
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return false;
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return Visit(S->getSubStmt());
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}
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};
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class EmptyStatementsRemover :
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public RecursiveASTVisitor<EmptyStatementsRemover> {
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MigrationPass &Pass;
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public:
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EmptyStatementsRemover(MigrationPass &pass) : Pass(pass) { }
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bool TraverseStmtExpr(StmtExpr *E) {
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CompoundStmt *S = E->getSubStmt();
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for (CompoundStmt::body_iterator
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I = S->body_begin(), E = S->body_end(); I != E; ++I) {
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if (I != E - 1)
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check(*I);
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TraverseStmt(*I);
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}
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return true;
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}
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bool VisitCompoundStmt(CompoundStmt *S) {
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for (auto *I : S->body())
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check(I);
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return true;
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}
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ASTContext &getContext() { return Pass.Ctx; }
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private:
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void check(Stmt *S) {
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if (!S) return;
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if (EmptyChecker(Pass.Ctx, Pass.ARCMTMacroLocs).Visit(S)) {
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Transaction Trans(Pass.TA);
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Pass.TA.removeStmt(S);
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}
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}
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};
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} // anonymous namespace
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static bool isBodyEmpty(CompoundStmt *body, ASTContext &Ctx,
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std::vector<SourceLocation> &MacroLocs) {
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for (auto *I : body->body())
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if (!EmptyChecker(Ctx, MacroLocs).Visit(I))
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return false;
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return true;
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}
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static void cleanupDeallocOrFinalize(MigrationPass &pass) {
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ASTContext &Ctx = pass.Ctx;
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TransformActions &TA = pass.TA;
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DeclContext *DC = Ctx.getTranslationUnitDecl();
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Selector FinalizeSel =
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Ctx.Selectors.getNullarySelector(&pass.Ctx.Idents.get("finalize"));
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typedef DeclContext::specific_decl_iterator<ObjCImplementationDecl>
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impl_iterator;
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for (impl_iterator I = impl_iterator(DC->decls_begin()),
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E = impl_iterator(DC->decls_end()); I != E; ++I) {
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ObjCMethodDecl *DeallocM = nullptr;
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ObjCMethodDecl *FinalizeM = nullptr;
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for (auto *MD : I->instance_methods()) {
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if (!MD->hasBody())
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continue;
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if (MD->getMethodFamily() == OMF_dealloc) {
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DeallocM = MD;
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} else if (MD->isInstanceMethod() && MD->getSelector() == FinalizeSel) {
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FinalizeM = MD;
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}
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}
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if (DeallocM) {
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if (isBodyEmpty(DeallocM->getCompoundBody(), Ctx, pass.ARCMTMacroLocs)) {
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Transaction Trans(TA);
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TA.remove(DeallocM->getSourceRange());
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}
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if (FinalizeM) {
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Transaction Trans(TA);
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TA.remove(FinalizeM->getSourceRange());
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}
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} else if (FinalizeM) {
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if (isBodyEmpty(FinalizeM->getCompoundBody(), Ctx, pass.ARCMTMacroLocs)) {
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Transaction Trans(TA);
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TA.remove(FinalizeM->getSourceRange());
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} else {
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Transaction Trans(TA);
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TA.replaceText(FinalizeM->getSelectorStartLoc(), "finalize", "dealloc");
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}
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}
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}
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}
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void trans::removeEmptyStatementsAndDeallocFinalize(MigrationPass &pass) {
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EmptyStatementsRemover(pass).TraverseDecl(pass.Ctx.getTranslationUnitDecl());
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cleanupDeallocOrFinalize(pass);
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for (unsigned i = 0, e = pass.ARCMTMacroLocs.size(); i != e; ++i) {
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Transaction Trans(pass.TA);
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pass.TA.remove(pass.ARCMTMacroLocs[i]);
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}
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}
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