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//===--- DataflowDiagnostics.cpp - Emits diagnostics based on SIL analysis ===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#include "swift/SILOptimizer/PassManager/Passes.h"
#include "swift/SILOptimizer/PassManager/Transforms.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/DiagnosticEngine.h"
#include "swift/AST/DiagnosticsSema.h"
#include "swift/AST/DiagnosticsSIL.h"
#include "swift/AST/Expr.h"
#include "swift/AST/Stmt.h"
#include "swift/SIL/SILFunction.h"
#include "swift/SIL/SILInstruction.h"
#include "swift/SIL/SILLocation.h"
#include "swift/SIL/SILModule.h"
#include "swift/SIL/SILVisitor.h"
using namespace swift;
template<typename...T, typename...U>
static void diagnose(ASTContext &Context, SourceLoc loc, Diag<T...> diag,
U &&...args) {
Context.Diags.diagnose(loc,
diag, std::forward<U>(args)...);
}
static void diagnoseMissingReturn(const UnreachableInst *UI,
ASTContext &Context) {
const SILBasicBlock *BB = UI->getParent();
const SILFunction *F = BB->getParent();
SILLocation FLoc = F->getLocation();
Type ResTy;
if (auto *FD = FLoc.getAsASTNode<FuncDecl>()) {
ResTy = FD->getResultInterfaceType();
} else if (auto *CD = FLoc.getAsASTNode<ConstructorDecl>()) {
ResTy = CD->getResultInterfaceType();
} else if (auto *CE = FLoc.getAsASTNode<ClosureExpr>()) {
ResTy = CE->getResultType();
} else {
llvm_unreachable("unhandled case in MissingReturn");
}
SILLocation L = UI->getLoc();
assert(L && ResTy);
auto diagID = F->isNoReturnFunction() ? diag::missing_never_call
: diag::missing_return;
diagnose(Context,
L.getEndSourceLoc(),
diagID, ResTy,
FLoc.isASTNode<ClosureExpr>() ? 1 : 0);
}
static void diagnoseUnreachable(const SILInstruction *I,
ASTContext &Context) {
if (auto *UI = dyn_cast<UnreachableInst>(I)) {
SILLocation L = UI->getLoc();
// Invalid location means that the instruction has been generated by SIL
// passes, such as DCE. FIXME: we might want to just introduce a separate
// instruction kind, instead of keeping this invariant.
//
// We also do not want to emit diagnostics for code that was
// transparently inlined. We should have already emitted these
// diagnostics when we process the callee function prior to
// inlining it.
if (!L || L.is<MandatoryInlinedLocation>())
return;
// The most common case of getting an unreachable instruction is a
// missing return statement. In this case, we know that the instruction
// location will be the enclosing function.
if (L.isASTNode<AbstractFunctionDecl>() || L.isASTNode<ClosureExpr>()) {
diagnoseMissingReturn(UI, Context);
return;
}
if (auto *Guard = L.getAsASTNode<GuardStmt>()) {
diagnose(Context, Guard->getBody()->getEndLoc(),
diag::guard_body_must_not_fallthrough);
return;
}
}
}
/// \brief Issue diagnostics whenever we see Builtin.static_report(1, ...).
static void diagnoseStaticReports(const SILInstruction *I,
SILModule &M) {
// Find out if we are dealing with Builtin.staticReport().
if (auto *BI = dyn_cast<BuiltinInst>(I)) {
const BuiltinInfo &B = BI->getBuiltinInfo();
if (B.ID == BuiltinValueKind::StaticReport) {
// Report diagnostic if the first argument has been folded to '1'.
OperandValueArrayRef Args = BI->getArguments();
auto *V = dyn_cast<IntegerLiteralInst>(Args[0]);
if (!V || V->getValue() != 1)
return;
diagnose(M.getASTContext(), I->getLoc().getSourceLoc(),
diag::static_report_error);
}
}
}
namespace {
class EmitDFDiagnostics : public SILFunctionTransform {
~EmitDFDiagnostics() override {}
/// The entry point to the transformation.
void run() override {
SILModule &M = getFunction()->getModule();
for (auto &BB : *getFunction())
for (auto &I : BB) {
diagnoseUnreachable(&I, M.getASTContext());
diagnoseStaticReports(&I, M);
}
}
};
} // end anonymous namespace
SILTransform *swift::createEmitDFDiagnostics() {
return new EmitDFDiagnostics();
}