Reapply r137903, but fix the definition of size_t in the test case to use __SIZE_TYPE__ (and hence be portable).
Also, change the warning to -Wstrl-incorrect-size.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137980 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 94e1c4f..882668e 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -319,7 +319,7 @@
TheCall->getCallee()->getLocStart());
}
- // Memset/memcpy/memmove/memcmp handling
+ // Builtin handling
int CMF = -1;
switch (FDecl->getBuiltinID()) {
case Builtin::BI__builtin_memset:
@@ -339,6 +339,11 @@
case Builtin::BImemmove:
CMF = CMF_Memmove;
break;
+
+ case Builtin::BIstrlcpy:
+ case Builtin::BIstrlcat:
+ CheckStrlcpycatArguments(TheCall, FnInfo);
+ break;
case Builtin::BI__builtin_memcmp:
CMF = CMF_Memcmp;
@@ -359,6 +364,7 @@
break;
}
+ // Memset/memcpy/memmove handling
if (CMF != -1)
CheckMemaccessArguments(TheCall, CheckedMemoryFunction(CMF), FnInfo);
@@ -1990,6 +1996,95 @@
}
}
+// A little helper routine: ignore addition and subtraction of integer literals.
+// This intentionally does not ignore all integer constant expressions because
+// we don't want to remove sizeof().
+static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) {
+ Ex = Ex->IgnoreParenCasts();
+
+ for (;;) {
+ const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex);
+ if (!BO || !BO->isAdditiveOp())
+ break;
+
+ const Expr *RHS = BO->getRHS()->IgnoreParenCasts();
+ const Expr *LHS = BO->getLHS()->IgnoreParenCasts();
+
+ if (isa<IntegerLiteral>(RHS))
+ Ex = LHS;
+ else if (isa<IntegerLiteral>(LHS))
+ Ex = RHS;
+ else
+ break;
+ }
+
+ return Ex;
+}
+
+// Warn if the user has made the 'size' argument to strlcpy or strlcat
+// be the size of the source, instead of the destination.
+void Sema::CheckStrlcpycatArguments(const CallExpr *Call,
+ IdentifierInfo *FnName) {
+
+ // Don't crash if the user has the wrong number of arguments
+ if (Call->getNumArgs() != 3)
+ return;
+
+ const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context);
+ const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context);
+ const Expr *CompareWithSrc = NULL;
+
+ // Look for 'strlcpy(dst, x, sizeof(x))'
+ if (const Expr *Ex = getSizeOfExprArg(SizeArg))
+ CompareWithSrc = Ex;
+ else {
+ // Look for 'strlcpy(dst, x, strlen(x))'
+ if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) {
+ if (SizeCall->isBuiltinCall(Context) == Builtin::BIstrlen
+ && SizeCall->getNumArgs() == 1)
+ CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context);
+ }
+ }
+
+ if (!CompareWithSrc)
+ return;
+
+ // Determine if the argument to sizeof/strlen is equal to the source
+ // argument. In principle there's all kinds of things you could do
+ // here, for instance creating an == expression and evaluating it with
+ // EvaluateAsBooleanCondition, but this uses a more direct technique:
+ const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg);
+ if (!SrcArgDRE)
+ return;
+
+ const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc);
+ if (!CompareWithSrcDRE ||
+ SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl())
+ return;
+
+ const Expr *OriginalSizeArg = Call->getArg(2);
+ Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size)
+ << OriginalSizeArg->getSourceRange() << FnName;
+
+ // Output a FIXIT hint if the destination is an array (rather than a
+ // pointer to an array). This could be enhanced to handle some
+ // pointers if we know the actual size, like if DstArg is 'array+2'
+ // we could say 'sizeof(array)-2'.
+ const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts();
+
+ if (DstArg->getType()->isArrayType()) {
+ llvm::SmallString<128> sizeString;
+ llvm::raw_svector_ostream OS(sizeString);
+ OS << "sizeof(";
+ DstArg->printPretty(OS, Context, 0, Context.PrintingPolicy);
+ OS << ")";
+
+ Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size)
+ << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(),
+ OS.str());
+ }
+}
+
//===--- CHECK: Return Address of Stack Variable --------------------------===//
static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars);