Tidy up sema processing of attribute "nonull":

- warn about nonnull being applied to functions with no pointer arguments
- continue processing argument list in the attribute when we encounter a non-pointer parameter being marked as nonnull
- when no argument list is specified, only mark pointers as nonnull.  This fixes PR 2732 and radar 6188814.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55610 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 28 insertions, 13 deletions

diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 3510e7dee6..95d2112650 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -692,7 +692,9 @@ DIAG(err_mode_wrong_type, ERROR,
      "type of machine mode does not match type of base type")
 DIAG(err_attr_wrong_decl, ERROR,
      "'%0' attribute invalid on this declaration, requires typedef or value")
-     
+DIAG(warn_attribute_nonnull_no_pointers, WARNING,
+  "'nonnull' attribute applied to function with no pointer arguments")
+  
 // Clang-Specific Attributes
 DIAG(err_attribute_iboutlet_non_ivar, ERROR,
      "'iboutlet' attribute can only be applied to instance variables")
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index f94711e987..eb9888e9a2 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -282,20 +282,32 @@ static void HandleNonNullAttr(Decl *d, const AttributeList &Attr, Sema &S) {
       // FIXME: Should also highlight argument in decl.
       S.Diag(Attr.getLoc(), diag::err_nonnull_pointers_only,
              "nonnull", Ex->getSourceRange());
-      return;    
+      continue;
     }
     
     NonNullArgs.push_back(x);
   }
   
-  if (!NonNullArgs.empty()) {
-    unsigned* start = &NonNullArgs[0];
-    unsigned size = NonNullArgs.size();
-    std::sort(start, start + size);
-    d->addAttr(new NonNullAttr(start, size));
+  // If no arguments were specified to __attribute__((nonnull)) then all
+  // pointer arguments have a nonnull attribute.
+  if (NonNullArgs.empty()) {
+    unsigned idx = 0;
+    
+    for (FunctionTypeProto::arg_type_iterator
+         I=proto->arg_type_begin(), E=proto->arg_type_end(); I!=E; ++I, ++idx)
+      if ((*I)->isPointerType())
+        NonNullArgs.push_back(idx);
+    
+    if (NonNullArgs.empty()) {
+      S.Diag(Attr.getLoc(), diag::warn_attribute_nonnull_no_pointers);
+      return;
+    }
   }
-  else
-    d->addAttr(new NonNullAttr());
+
+  unsigned* start = &NonNullArgs[0];
+  unsigned size = NonNullArgs.size();
+  std::sort(start, start + size);
+  d->addAttr(new NonNullAttr(start, size));
 }
 
 static void HandleAliasAttr(Decl *d, const AttributeList &Attr, Sema &S) {
diff --git a/test/Analysis/null-deref-ps.c b/test/Analysis/null-deref-ps.c
index 92e8daa57e..06f67da45a 100644
--- a/test/Analysis/null-deref-ps.c
+++ b/test/Analysis/null-deref-ps.c
@@ -56,11 +56,12 @@ int f5() {
   return s[0]; // no-warning
 }
 
-int bar(int* p) __attribute__((nonnull));
+int bar(int* p, int q) __attribute__((nonnull));
 
 int f6(int *p) { 
-  return !p ? bar(p) : *p; // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
-} 
+  return !p ? bar(p, 1) // expected-warning {{Null pointer passed as an argument to a 'nonnull' parameter}}
+         : bar(p, 0);   // no-warning
+}
 
 int* qux();
 
diff --git a/test/Sema/nonnull.c b/test/Sema/nonnull.c
index f8a2a0ed78..9a64ce4320 100644
--- a/test/Sema/nonnull.c
+++ b/test/Sema/nonnull.c
@@ -1,6 +1,6 @@
 // RUN: clang -fsyntax-only -verify %s
 
-int f1(int x) __attribute__((nonnull));
+int f1(int x) __attribute__((nonnull)); // expected-warning{{'nonnull' attribute applied to function with no pointer arguments}}
 int f2(int *x) __attribute__ ((nonnull (1)));
 int f3(int *x) __attribute__ ((nonnull (0))); // expected-error {{'nonnull' attribute parameter 1 is out of bounds}}
 int f4(int *x, int *y) __attribute__ ((nonnull (1,2)));