void CodeGenFunction::EmitForStmt(const ForStmt &S) {
// FIXME: What do we do if the increment (f.e.) contains a stmt expression,
// which contains a continue/break?
// Evaluate the first part before the loop.
if (S.getInit())
EmitStmt(S.getInit());
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
llvm::BasicBlock *AfterFor = createBasicBlock("for.end");
EmitBlock(CondBlock);
// Evaluate the condition if present. If not, treat it as a
// non-zero-constant according to 6.8.5.3p2, aka, true.
if (S.getCond()) {
// As long as the condition is true, iterate the loop.
llvm::BasicBlock *ForBody = createBasicBlock("for.body");
// C99 6.8.5p2/p4: The first substatement is executed if the expression
// compares unequal to 0. The condition must be a scalar type.
EmitBranchOnBoolExpr(S.getCond(), ForBody, AfterFor);
EmitBlock(ForBody);
} else {
// Treat it as a non-zero constant. Don't even create a new block for the
// body, just fall into it.
}
// If the for loop doesn't have an increment we can just use the
// condition as the continue block.
llvm::BasicBlock *ContinueBlock;
if (S.getInc())
ContinueBlock = createBasicBlock("for.inc");
else
ContinueBlock = CondBlock;
// Store the blocks to use for break and continue.
BreakContinueStack.push_back(BreakContinue(AfterFor, ContinueBlock));
// If the condition is true, execute the body of the for stmt.
EmitStmt(S.getBody());
BreakContinueStack.pop_back();
// If there is an increment, emit it next.
if (S.getInc()) {
EmitBlock(ContinueBlock);
EmitStmt(S.getInc());
}
// Finally, branch back up to the condition for the next iteration.
EmitBranch(CondBlock);
// Emit the fall-through block.
EmitBlock(AfterFor, true);
}
bool VisitForStmt(ForStmt *parentStmt)
{
Stmt *bodyStmt = parentStmt->getBody();
ForStmt *forStmt = dyn_cast_or_null<ForStmt>(bodyStmt);
CompoundStmt *compoundStmt = dyn_cast_or_null<CompoundStmt>(bodyStmt);
if (!forStmt && compoundStmt && compoundStmt->size() == 1)
{
forStmt = dyn_cast_or_null<ForStmt>(compoundStmt->body_back());
}
if (forStmt)
{
Stmt *initStmt = parentStmt->getInit();
Expr *incExpr = forStmt->getInc();
if (isInnerIncMatchingOuterInit(incExpr, initStmt))
{
addViolation(incExpr, this);
}
}
return true;
}
