[arcmt] Allow removing an -autorelease of a variable initialized in the previous statement.
rdar://11074996
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171485 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index 97d9bff..0c8d155 100644
--- a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -174,7 +174,7 @@
/// return var;
///
bool isCommonUnusedAutorelease(ObjCMessageExpr *E) {
- if (isPlusOneAssignAfterAutorelease(E))
+ if (isPlusOneAssignBeforeOrAfterAutorelease(E))
return true;
if (isReturnedAfterAutorelease(E))
return true;
@@ -202,7 +202,7 @@
return false;
}
- bool isPlusOneAssignAfterAutorelease(ObjCMessageExpr *E) {
+ bool isPlusOneAssignBeforeOrAfterAutorelease(ObjCMessageExpr *E) {
Expr *Rec = E->getInstanceReceiver();
if (!Rec)
return false;
@@ -211,24 +211,46 @@
if (!RefD)
return false;
- Stmt *nextStmt = getNextStmt(E);
- if (!nextStmt)
+ Stmt *prevStmt, *nextStmt;
+ llvm::tie(prevStmt, nextStmt) = getPreviousAndNextStmt(E);
+
+ return isPlusOneAssignToVar(prevStmt, RefD) ||
+ isPlusOneAssignToVar(nextStmt, RefD);
+ }
+
+ bool isPlusOneAssignToVar(Stmt *S, Decl *RefD) {
+ if (!S)
return false;
// Check for "RefD = [+1 retained object];".
- if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(nextStmt)) {
+ if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
if (RefD != getReferencedDecl(Bop->getLHS()))
return false;
if (isPlusOneAssign(Bop))
return true;
+ return false;
}
+
+ if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
+ if (DS->isSingleDecl() && DS->getSingleDecl() == RefD) {
+ if (VarDecl *VD = dyn_cast<VarDecl>(RefD))
+ return isPlusOne(VD->getInit());
+ }
+ return false;
+ }
+
return false;
}
Stmt *getNextStmt(Expr *E) {
+ return getPreviousAndNextStmt(E).second;
+ }
+
+ std::pair<Stmt *, Stmt *> getPreviousAndNextStmt(Expr *E) {
+ Stmt *prevStmt = 0, *nextStmt = 0;
if (!E)
- return 0;
+ return std::make_pair(prevStmt, nextStmt);
Stmt *OuterS = E, *InnerS;
do {
@@ -240,24 +262,34 @@
isa<ExprWithCleanups>(OuterS)));
if (!OuterS)
- return 0;
+ return std::make_pair(prevStmt, nextStmt);
Stmt::child_iterator currChildS = OuterS->child_begin();
Stmt::child_iterator childE = OuterS->child_end();
+ Stmt::child_iterator prevChildS = childE;
for (; currChildS != childE; ++currChildS) {
if (*currChildS == InnerS)
break;
+ prevChildS = currChildS;
}
+
+ if (prevChildS != childE) {
+ prevStmt = *prevChildS;
+ if (prevStmt)
+ prevStmt = prevStmt->IgnoreImplicit();
+ }
+
if (currChildS == childE)
- return 0;
+ return std::make_pair(prevStmt, nextStmt);
++currChildS;
if (currChildS == childE)
- return 0;
+ return std::make_pair(prevStmt, nextStmt);
- Stmt *nextStmt = *currChildS;
- if (!nextStmt)
- return 0;
- return nextStmt->IgnoreImplicit();
+ nextStmt = *currChildS;
+ if (nextStmt)
+ nextStmt = nextStmt->IgnoreImplicit();
+
+ return std::make_pair(prevStmt, nextStmt);
}
Decl *getReferencedDecl(Expr *E) {
diff --git a/lib/ARCMigrate/Transforms.cpp b/lib/ARCMigrate/Transforms.cpp
index 938f015..136f618 100644
--- a/lib/ARCMigrate/Transforms.cpp
+++ b/lib/ARCMigrate/Transforms.cpp
@@ -71,13 +71,22 @@
if (E->getOpcode() != BO_Assign)
return false;
+ return isPlusOne(E->getRHS());
+}
+
+bool trans::isPlusOne(const Expr *E) {
+ if (!E)
+ return false;
+ if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E))
+ E = EWC->getSubExpr();
+
if (const ObjCMessageExpr *
- ME = dyn_cast<ObjCMessageExpr>(E->getRHS()->IgnoreParenCasts()))
+ ME = dyn_cast<ObjCMessageExpr>(E->IgnoreParenCasts()))
if (ME->getMethodFamily() == OMF_retain)
return true;
if (const CallExpr *
- callE = dyn_cast<CallExpr>(E->getRHS()->IgnoreParenCasts())) {
+ callE = dyn_cast<CallExpr>(E->IgnoreParenCasts())) {
if (const FunctionDecl *FD = callE->getDirectCallee()) {
if (FD->getAttr<CFReturnsRetainedAttr>())
return true;
@@ -98,7 +107,7 @@
}
}
- const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E->getRHS());
+ const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E);
while (implCE && implCE->getCastKind() == CK_BitCast)
implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());
diff --git a/lib/ARCMigrate/Transforms.h b/lib/ARCMigrate/Transforms.h
index 69e91e7..cb7d153 100644
--- a/lib/ARCMigrate/Transforms.h
+++ b/lib/ARCMigrate/Transforms.h
@@ -161,6 +161,7 @@
bool AllowOnUnknownClass = false);
bool isPlusOneAssign(const BinaryOperator *E);
+bool isPlusOne(const Expr *E);
/// \brief 'Loc' is the end of a statement range. This returns the location
/// immediately after the semicolon following the statement.
diff --git a/test/ARCMT/autoreleases.m b/test/ARCMT/autoreleases.m
index d491394..543bcf6 100644
--- a/test/ARCMT/autoreleases.m
+++ b/test/ARCMT/autoreleases.m
@@ -69,3 +69,8 @@
[[val retain] autorelease];
return val;
}
+
+id test3() {
+ id a = [[A alloc] init];
+ [a autorelease];
+}
diff --git a/test/ARCMT/autoreleases.m.result b/test/ARCMT/autoreleases.m.result
index 76ce8cf..9b71ff8 100644
--- a/test/ARCMT/autoreleases.m.result
+++ b/test/ARCMT/autoreleases.m.result
@@ -64,3 +64,7 @@
id test2(A* val) {
return val;
}
+
+id test3() {
+ id a = [[A alloc] init];
+}