commit 588bd9b7f869578e80c4359694425a5fd20e3ebd
author Richard Smith <richard-llvm@metafoo.co.uk> Wed Aug 27 04:59:42 2014 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Wed Aug 27 04:59:42 2014 +0000
tree a128c29aad9b61368c5b0f12d776a2cbb5a29fa6
parent 88d786eab827ca485e31f256e4b5a2cf93fc6b50

Fix representation of __attribute__((nonnull)) to support correctly modeling
the no-arguments case. Don't expand this to an __attribute__((nonnull(A, B,
C))) attribute, since that does the wrong thing for function templates and
varargs functions.

In passing, fix a grammar error in the diagnostic, a crash if
__attribute__((nonnull(N))) is applied to a varargs function,
a bug where the same null argument could be diagnosed multiple
times if there were multiple nonnull attributes referring to it,
and a bug where nonnull attributes would not be accumulated correctly
across redeclarations.

llvm-svn: 216520

clang/lib/Sema/SemaChecking.cpp

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 331c5b3..c1263d4 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -764,12 +764,26 @@
 
 static void CheckNonNullArguments(Sema &S,
                                   const NamedDecl *FDecl,
-                                  const Expr * const *ExprArgs,
+                                  ArrayRef<const Expr *> Args,
                                   SourceLocation CallSiteLoc) {
   // Check the attributes attached to the method/function itself.
+  llvm::SmallBitVector NonNullArgs;
   for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) {
-    for (const auto &Val : NonNull->args())
-      CheckNonNullArgument(S, ExprArgs[Val], CallSiteLoc);
+    if (!NonNull->args_size()) {
+      // Easy case: all pointer arguments are nonnull.
+      for (const auto *Arg : Args)
+        if (S.isValidNonNullAttrType(Arg->getType()))
+          CheckNonNullArgument(S, Arg, CallSiteLoc);
+      return;
+    }
+
+    for (unsigned Val : NonNull->args()) {
+      if (Val >= Args.size())
+        continue;
+      if (NonNullArgs.empty())
+        NonNullArgs.resize(Args.size());
+      NonNullArgs.set(Val);
+    }
   }
 
   // Check the attributes on the parameters.
@@ -779,13 +793,19 @@
   else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(FDecl))
     parms = MD->parameters();
 
-  unsigned argIndex = 0;
+  unsigned ArgIndex = 0;
   for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end();
-       I != E; ++I, ++argIndex) {
+       I != E; ++I, ++ArgIndex) {
     const ParmVarDecl *PVD = *I;
-    if (PVD->hasAttr<NonNullAttr>())
-      CheckNonNullArgument(S, ExprArgs[argIndex], CallSiteLoc);
+    if (PVD->hasAttr<NonNullAttr>() ||
+        (ArgIndex < NonNullArgs.size() && NonNullArgs[ArgIndex]))
+      CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc);
   }
+
+  // In case this is a variadic call, check any remaining arguments.
+  for (/**/; ArgIndex < NonNullArgs.size(); ++ArgIndex)
+    if (NonNullArgs[ArgIndex])
+      CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc);
 }
 
 /// Handles the checks for format strings, non-POD arguments to vararg
@@ -823,7 +843,7 @@
   }
 
   if (FDecl) {
-    CheckNonNullArguments(*this, FDecl, Args.data(), Loc);
+    CheckNonNullArguments(*this, FDecl, Args, Loc);
 
     // Type safety checking.
     for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>())