Update Clang for 3.5 rebase (r209713).
Change-Id: I8c9133b0f8f776dc915f270b60f94962e771bc83
diff --git a/lib/Analysis/ReachableCode.cpp b/lib/Analysis/ReachableCode.cpp
index 3cc8ae4..b4a72a7 100644
--- a/lib/Analysis/ReachableCode.cpp
+++ b/lib/Analysis/ReachableCode.cpp
@@ -59,32 +59,57 @@
}
static bool isDeadReturn(const CFGBlock *B, const Stmt *S) {
- // Look to see if the block ends with a 'return', and see if 'S'
- // is a substatement. The 'return' may not be the last element in
- // the block because of destructors.
- for (CFGBlock::const_reverse_iterator I = B->rbegin(), E = B->rend();
- I != E; ++I) {
- if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
- if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(CS->getStmt())) {
- if (RS == S)
- return true;
- if (const Expr *RE = RS->getRetValue()) {
- RE = RE->IgnoreParenCasts();
- if (RE == S)
+ // Look to see if the current control flow ends with a 'return', and see if
+ // 'S' is a substatement. The 'return' may not be the last element in the
+ // block, or may be in a subsequent block because of destructors.
+ const CFGBlock *Current = B;
+ while (true) {
+ for (CFGBlock::const_reverse_iterator I = Current->rbegin(),
+ E = Current->rend();
+ I != E; ++I) {
+ if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
+ if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(CS->getStmt())) {
+ if (RS == S)
return true;
- ParentMap PM(const_cast<Expr*>(RE));
- // If 'S' is in the ParentMap, it is a subexpression of
- // the return statement. Note also that we are restricting
- // to looking at return statements in the same CFGBlock,
- // so this will intentionally not catch cases where the
- // return statement contains nested control-flow.
- return PM.getParent(S);
+ if (const Expr *RE = RS->getRetValue()) {
+ RE = RE->IgnoreParenCasts();
+ if (RE == S)
+ return true;
+ ParentMap PM(const_cast<Expr *>(RE));
+ // If 'S' is in the ParentMap, it is a subexpression of
+ // the return statement.
+ return PM.getParent(S);
+ }
}
+ break;
}
- break;
+ }
+ // Note also that we are restricting the search for the return statement
+ // to stop at control-flow; only part of a return statement may be dead,
+ // without the whole return statement being dead.
+ if (Current->getTerminator().isTemporaryDtorsBranch()) {
+ // Temporary destructors have a predictable control flow, thus we want to
+ // look into the next block for the return statement.
+ // We look into the false branch, as we know the true branch only contains
+ // the call to the destructor.
+ assert(Current->succ_size() == 2);
+ Current = *(Current->succ_begin() + 1);
+ } else if (!Current->getTerminator() && Current->succ_size() == 1) {
+ // If there is only one successor, we're not dealing with outgoing control
+ // flow. Thus, look into the next block.
+ Current = *Current->succ_begin();
+ if (Current->pred_size() > 1) {
+ // If there is more than one predecessor, we're dealing with incoming
+ // control flow - if the return statement is in that block, it might
+ // well be reachable via a different control flow, thus it's not dead.
+ return false;
+ }
+ } else {
+ // We hit control flow or a dead end. Stop searching.
+ return false;
}
}
- return false;
+ llvm_unreachable("Broke out of infinite loop.");
}
static SourceLocation getTopMostMacro(SourceLocation Loc, SourceManager &SM) {
@@ -139,6 +164,9 @@
if (!S)
return false;
+ if (const Expr *Ex = dyn_cast<Expr>(S))
+ S = Ex->IgnoreCasts();
+
// Special case looking for the sigil '()' around an integer literal.
if (const ParenExpr *PE = dyn_cast<ParenExpr>(S))
if (!PE->getLocStart().isMacroID())
@@ -146,7 +174,7 @@
IncludeIntegers, true);
if (const Expr *Ex = dyn_cast<Expr>(S))
- S = Ex->IgnoreParenCasts();
+ S = Ex->IgnoreCasts();
bool IgnoreYES_NO = false;
@@ -399,7 +427,7 @@
}
}
- return 0;
+ return nullptr;
}
static int SrcCmp(const std::pair<const CFGBlock *, const Stmt *> *p1,
@@ -603,7 +631,7 @@
unsigned ScanReachableFromBlock(const CFGBlock *Start,
llvm::BitVector &Reachable) {
- return scanFromBlock(Start, Reachable, /* SourceManager* */ 0, false);
+ return scanFromBlock(Start, Reachable, /* SourceManager* */ nullptr, false);
}
void FindUnreachableCode(AnalysisDeclContext &AC, Preprocessor &PP,