r216574 - Fix regression in r216520: don't apply nonnull to non-pointer function

[Richard Smith]

Author: rsmith
Date: Wed Aug 27 13:56:18 2014
New Revision: 216574

URL: http://llvm.org/viewvc/llvm-project?rev=216574&view=rev
Log:
Fix regression in r216520: don't apply nonnull to non-pointer function
parameters in the IR.

Modified:
    cfe/trunk/lib/CodeGen/CGCall.cpp
    cfe/trunk/test/CodeGen/nonnull.c

Modified: cfe/trunk/lib/CodeGen/CGCall.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=216574&r1=216573&r2=216574&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGCall.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGCall.cpp Wed Aug 27 13:56:18 2014
@@ -1557,8 +1557,17 @@ void CodeGenFunction::EmitFunctionProlog
         llvm::Value *V = AI;
 
         if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Arg)) {
-          if ((NNAtt && NNAtt->isNonNull(PVD->getFunctionScopeIndex())) ||
-              PVD->hasAttr<NonNullAttr>())
+          // FIXME: __attribute__((nonnull)) can also be applied to:
+          //   - references to pointers, where the pointee is known to be
+          //     nonnull (apparently a Clang extension)
+          //   - transparent unions containing pointers
+          // In the former case, LLVM IR cannot represent the constraint. In
+          // the latter case, we have no guarantee that the transparent union
+          // is in fact passed as a pointer.
+          if (((NNAtt && NNAtt->isNonNull(PVD->getFunctionScopeIndex())) ||
+               PVD->hasAttr<NonNullAttr>()) &&
+              (PVD->getType()->isAnyPointerType() ||
+               PVD->getType()->isBlockPointerType()))
             AI->addAttr(llvm::AttributeSet::get(getLLVMContext(),
                                                 AI->getArgNo() + 1,
                                                 llvm::Attribute::NonNull));

Modified: cfe/trunk/test/CodeGen/nonnull.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/nonnull.c?rev=216574&r1=216573&r2=216574&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/nonnull.c (original)
+++ cfe/trunk/test/CodeGen/nonnull.c Wed Aug 27 13:56:18 2014
@@ -21,3 +21,23 @@ int * bar3() __attribute__((returns_nonn
   return &a;
 }
 
+// CHECK: define i32 @bar4(i32 %n, i32* nonnull %p)
+int bar4(int n, int *p) __attribute__((nonnull)) {
+  return n + *p;
+}
+
+// CHECK: define i32 @bar5(i32 %n, i32* nonnull %p)
+int bar5(int n, int *p) __attribute__((nonnull(1, 2))) {
+  return n + *p;
+}
+
+typedef union {
+  unsigned long long n;
+  int *p;
+  double d;
+} TransparentUnion __attribute__((transparent_union));
+
+// CHECK: define i32 @bar6(i64 %
+int bar6(TransparentUnion tu) __attribute__((nonnull(1))) {
+  return *tu.p;
+}