mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-27 16:16:11 +00:00
7a51313d8a
lib dir and move all the libraries into it. This follows the main llvm tree, and allows the libraries to be built in parallel. The top level now enforces that all the libs are built before Driver, but we don't care what order the libs are built in. This speeds up parallel builds, particularly incremental ones. llvm-svn: 48402
88 lines
3.1 KiB
C++
88 lines
3.1 KiB
C++
//==- DeadStores.cpp - Check for stores to dead variables --------*- C++ -*-==//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines a DeadStores, a flow-sensitive checker that looks for
|
|
// stores to variables that are no longer live.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "clang/Analysis/LocalCheckers.h"
|
|
#include "clang/Analysis/Analyses/LiveVariables.h"
|
|
#include "clang/Analysis/Visitors/CFGRecStmtVisitor.h"
|
|
#include "clang/Basic/Diagnostic.h"
|
|
#include "clang/AST/ASTContext.h"
|
|
#include "llvm/Support/Compiler.h"
|
|
|
|
using namespace clang;
|
|
|
|
namespace {
|
|
|
|
class VISIBILITY_HIDDEN DeadStoreObs : public LiveVariables::ObserverTy {
|
|
ASTContext &Ctx;
|
|
Diagnostic &Diags;
|
|
public:
|
|
DeadStoreObs(ASTContext &ctx,Diagnostic &diags) : Ctx(ctx), Diags(diags){}
|
|
virtual ~DeadStoreObs() {}
|
|
|
|
virtual void ObserveStmt(Stmt* S,
|
|
const LiveVariables::AnalysisDataTy& AD,
|
|
const LiveVariables::ValTy& Live) {
|
|
|
|
if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
|
|
if (!B->isAssignmentOp()) return; // Skip non-assignments.
|
|
|
|
if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(B->getLHS()))
|
|
if (VarDecl* VD = dyn_cast<VarDecl>(DR->getDecl()))
|
|
if (VD->hasLocalStorage() && !Live(VD,AD)) {
|
|
SourceRange R = B->getRHS()->getSourceRange();
|
|
Diags.Report(Ctx.getFullLoc(DR->getSourceRange().getBegin()),
|
|
diag::warn_dead_store, 0, 0, &R, 1);
|
|
}
|
|
}
|
|
else if(DeclStmt* DS = dyn_cast<DeclStmt>(S))
|
|
// Iterate through the decls. Warn if any initializers are complex
|
|
// expressions that are not live (never used).
|
|
for (VarDecl* V = cast<VarDecl>(DS->getDecl()); V != NULL ;
|
|
V = cast_or_null<VarDecl>(V->getNextDeclarator())) {
|
|
if (V->hasLocalStorage())
|
|
if (Expr* E = V->getInit()) {
|
|
if (!Live(DS->getDecl(),AD)) {
|
|
// Special case: check for initializations with constants.
|
|
//
|
|
// e.g. : int x = 0;
|
|
//
|
|
// If x is EVER assigned a new value later, don't issue
|
|
// a warning. This is because such initialization can be
|
|
// due to defensive programming.
|
|
if (!E->isConstantExpr(Ctx,NULL)) {
|
|
// Flag a warning.
|
|
SourceRange R = E->getSourceRange();
|
|
Diags.Report(Ctx.getFullLoc(V->getLocation()),
|
|
diag::warn_dead_store, 0, 0, &R, 1);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
namespace clang {
|
|
|
|
void CheckDeadStores(CFG& cfg, ASTContext &Ctx, Diagnostic &Diags) {
|
|
|
|
LiveVariables L(cfg);
|
|
L.runOnCFG(cfg);
|
|
DeadStoreObs A(Ctx, Diags);
|
|
L.runOnAllBlocks(cfg, &A);
|
|
}
|
|
|
|
} // end namespace clang
|