[Sema][OpenCL] Make address space conversions a bit stricter.

The semantics for converting nested pointers between address
spaces are not very well defined. Some conversions which do not
really carry any meaning only produce warnings, and in some cases
warnings hide invalid conversions, such as 'global int*' to
'local float*'!

This patch changes the logic in checkPointerTypesForAssignment
and checkAddressSpaceCast to fail properly on implicit conversions
that should definitely not be permitted. We also dig deeper into the
pointer types and warn on explicit conversions where the address
space in a nested pointer changes, regardless of whether the address
space is compatible with the corresponding pointer nesting level
on the destination type.

Fixes PR39674!

Patch by ebevhan (Bevin Hansson)!

Differential Revision: https://reviews.llvm.org/D58236



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@360258 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 179 insertions, 30 deletions

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 9205405853..ba376d5f10 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -7005,6 +7005,19 @@ def err_typecheck_incompatible_address_space : Error<
   "sending to parameter of different type}0,1"
   "|%diff{casting $ to type $|casting between types}0,1}2"
   " changes address space of pointer">;
+def err_typecheck_incompatible_nested_address_space : Error<
+  "%select{%diff{assigning $ to $|assigning to different types}1,0"
+  "|%diff{passing $ to parameter of type $|"
+  "passing to parameter of different type}0,1"
+  "|%diff{returning $ from a function with result type $|"
+  "returning from function with different return type}0,1"
+  "|%diff{converting $ to type $|converting between types}0,1"
+  "|%diff{initializing $ with an expression of type $|"
+  "initializing with expression of different type}0,1"
+  "|%diff{sending $ to parameter of type $|"
+  "sending to parameter of different type}0,1"
+  "|%diff{casting $ to type $|casting between types}0,1}2"
+  " changes address space of nested pointer">;
 def err_typecheck_incompatible_ownership : Error<
   "%select{%diff{assigning $ to $|assigning to different types}1,0"
   "|%diff{passing $ to parameter of type $|"
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 0ce34251e9..5f29fb8244 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -9726,6 +9726,12 @@ public:
     /// like address spaces.
     IncompatiblePointerDiscardsQualifiers,
 
+    /// IncompatibleNestedPointerAddressSpaceMismatch - The assignment
+    /// changes address spaces in nested pointer types which is not allowed.
+    /// For instance, converting __private int ** to __generic int ** is
+    /// illegal even though __private could be converted to __generic.
+    IncompatibleNestedPointerAddressSpaceMismatch,
+
     /// IncompatibleNestedPointerQualifiers - The assignment is between two
     /// nested pointer types, and the qualifiers other than the first two
     /// levels differ e.g. char ** -> const char **, but we accept them as an
diff --git a/lib/Sema/SemaCast.cpp b/lib/Sema/SemaCast.cpp
index 21a4d107ba..0958943f9e 100644
--- a/lib/Sema/SemaCast.cpp
+++ b/lib/Sema/SemaCast.cpp
@@ -2323,19 +2323,41 @@ void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) {
   // In OpenCL only conversions between pointers to objects in overlapping
   // addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps
   // with any named one, except for constant.
+
+  // Converting the top level pointee addrspace is permitted for compatible
+  // addrspaces (such as 'generic int *' to 'local int *' or vice versa), but
+  // if any of the nested pointee addrspaces differ, we emit a warning
+  // regardless of addrspace compatibility. This makes
+  //   local int ** p;
+  //   return (generic int **) p;
+  // warn even though local -> generic is permitted.
   if (Self.getLangOpts().OpenCL) {
-    auto SrcPtrType = SrcType->getAs<PointerType>();
-    if (!SrcPtrType)
-      return;
-    auto DestPtrType = DestType->getAs<PointerType>();
-    if (!DestPtrType)
-      return;
-    if (!DestPtrType->isAddressSpaceOverlapping(*SrcPtrType)) {
-      Self.Diag(OpRange.getBegin(),
-                diag::err_typecheck_incompatible_address_space)
-          << SrcType << DestType << Sema::AA_Casting
-          << SrcExpr.get()->getSourceRange();
-      SrcExpr = ExprError();
+    const Type *DestPtr, *SrcPtr;
+    bool Nested = false;
+    unsigned DiagID = diag::err_typecheck_incompatible_address_space;
+    DestPtr = Self.getASTContext().getCanonicalType(DestType.getTypePtr()),
+    SrcPtr  = Self.getASTContext().getCanonicalType(SrcType.getTypePtr());
+
+    while (isa<PointerType>(DestPtr) && isa<PointerType>(SrcPtr)) {
+      const PointerType *DestPPtr = cast<PointerType>(DestPtr);
+      const PointerType *SrcPPtr = cast<PointerType>(SrcPtr);
+      QualType DestPPointee = DestPPtr->getPointeeType();
+      QualType SrcPPointee = SrcPPtr->getPointeeType();
+      if (Nested ? DestPPointee.getAddressSpace() !=
+                   SrcPPointee.getAddressSpace()
+                 : !DestPPtr->isAddressSpaceOverlapping(*SrcPPtr)) {
+        Self.Diag(OpRange.getBegin(), DiagID)
+            << SrcType << DestType << Sema::AA_Casting
+            << SrcExpr.get()->getSourceRange();
+        if (!Nested)
+          SrcExpr = ExprError();
+        return;
+      }
+
+      DestPtr = DestPPtr->getPointeeType().getTypePtr();
+      SrcPtr = SrcPPtr->getPointeeType().getTypePtr();
+      Nested = true;
+      DiagID = diag::ext_nested_pointer_qualifier_mismatch;
     }
   }
 }
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index d8c0896147..8bb306e66d 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -7724,9 +7724,9 @@ checkPointerTypesForAssignment(Sema &S, QualType LHSType, QualType RHSType) {
   }
 
   if (!lhq.compatiblyIncludes(rhq)) {
-    // Treat address-space mismatches as fatal.  TODO: address subspaces
+    // Treat address-space mismatches as fatal.
     if (!lhq.isAddressSpaceSupersetOf(rhq))
-      ConvTy = Sema::IncompatiblePointerDiscardsQualifiers;
+      return Sema::IncompatiblePointerDiscardsQualifiers;
 
     // It's okay to add or remove GC or lifetime qualifiers when converting to
     // and from void*.
@@ -7799,8 +7799,22 @@ checkPointerTypesForAssignment(Sema &S, QualType LHSType, QualType RHSType) {
     // level of indirection, this must be the issue.
     if (isa<PointerType>(lhptee) && isa<PointerType>(rhptee)) {
       do {
-        lhptee = cast<PointerType>(lhptee)->getPointeeType().getTypePtr();
-        rhptee = cast<PointerType>(rhptee)->getPointeeType().getTypePtr();
+        std::tie(lhptee, lhq) =
+          cast<PointerType>(lhptee)->getPointeeType().split().asPair();
+        std::tie(rhptee, rhq) =
+          cast<PointerType>(rhptee)->getPointeeType().split().asPair();
+
+        // Inconsistent address spaces at this point is invalid, even if the
+        // address spaces would be compatible.
+        // FIXME: This doesn't catch address space mismatches for pointers of
+        // different nesting levels, like:
+        //   __local int *** a;
+        //   int ** b = a;
+        // It's not clear how to actually determine when such pointers are
+        // invalidly incompatible.
+        if (lhq.getAddressSpace() != rhq.getAddressSpace())
+          return Sema::IncompatibleNestedPointerAddressSpaceMismatch;
+
       } while (isa<PointerType>(lhptee) && isa<PointerType>(rhptee));
 
       if (lhptee == rhptee)
@@ -14213,6 +14227,9 @@ bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
   case IncompatibleNestedPointerQualifiers:
     DiagKind = diag::ext_nested_pointer_qualifier_mismatch;
     break;
+  case IncompatibleNestedPointerAddressSpaceMismatch:
+    DiagKind = diag::err_typecheck_incompatible_nested_address_space;
+    break;
   case IntToBlockPointer:
     DiagKind = diag::err_int_to_block_pointer;
     break;
diff --git a/test/CodeGenOpenCL/numbered-address-space.cl b/test/CodeGenOpenCL/numbered-address-space.cl
index dbaba87476..296923ee50 100644
--- a/test/CodeGenOpenCL/numbered-address-space.cl
+++ b/test/CodeGenOpenCL/numbered-address-space.cl
@@ -11,12 +11,6 @@ void test_numbered_as_to_generic(__attribute__((address_space(42))) int *arbitar
   *generic_ptr = 4;
 }
 
-// CHECK-LABEL: @test_numbered_as_to_builtin(
-// CHECK: addrspacecast i32 addrspace(42)* %0 to float addrspace(3)*
-void test_numbered_as_to_builtin(__attribute__((address_space(42))) int *arbitary_numbered_ptr, float src) {
-  volatile float result = __builtin_amdgcn_ds_fmaxf(arbitary_numbered_ptr, src, 0, 0, false);
-}
-
 // CHECK-LABEL: @test_generic_as_to_builtin_parameter_explicit_cast(
 // CHECK: addrspacecast i32 addrspace(3)* %0 to i32*
 void test_generic_as_to_builtin_parameter_explicit_cast(__local int *local_ptr, float src) {
@@ -25,10 +19,7 @@ void test_generic_as_to_builtin_parameter_explicit_cast(__local int *local_ptr,
 }
 
 // CHECK-LABEL: @test_generic_as_to_builtin_parameter_implicit_cast(
-// CHECK: addrspacecast i32* %2 to float addrspace(3)*
+// CHECK: bitcast i32 addrspace(3)* %0 to float addrspace(3)*
 void test_generic_as_to_builtin_parameter_implicit_cast(__local int *local_ptr, float src) {
-  generic int* generic_ptr = local_ptr;
-
-  volatile float result = __builtin_amdgcn_ds_fmaxf(generic_ptr, src, 0, 0, false);
+  volatile float result = __builtin_amdgcn_ds_fmaxf(local_ptr, src, 0, 0, false);
 }
-
diff --git a/test/SemaOpenCL/address-spaces.cl b/test/SemaOpenCL/address-spaces.cl
index f5fa43d922..13e9442b95 100644
--- a/test/SemaOpenCL/address-spaces.cl
+++ b/test/SemaOpenCL/address-spaces.cl
@@ -124,6 +124,106 @@ void ok_explicit_casts(__global int *g, __global int *g2, __local int *l, __loca
   p = (__private int *)p2;
 }
 
+#if !__OPENCL_CPP_VERSION__
+void nested(__global int *g, __global int * __private *gg, __local int *l, __local int * __private *ll, __global float * __private *gg_f) {
+  g = gg;    // expected-error {{assigning '__global int **' to '__global int *' changes address space of pointer}}
+  g = l;     // expected-error {{assigning '__local int *' to '__global int *' changes address space of pointer}}
+  g = ll;    // expected-error {{assigning '__local int **' to '__global int *' changes address space of pointer}}
+  g = gg_f;  // expected-error {{assigning '__global float **' to '__global int *' changes address space of pointer}}
+  g = (__global int *)gg_f; // expected-error {{casting '__global float **' to type '__global int *' changes address space of pointer}}
+
+  gg = g;    // expected-error {{assigning '__global int *' to '__global int **' changes address space of pointer}}
+  gg = l;    // expected-error {{assigning '__local int *' to '__global int **' changes address space of pointer}}
+  gg = ll;   // expected-error {{assigning '__local int **' to '__global int **' changes address space of nested pointer}}
+  gg = gg_f; // expected-warning {{incompatible pointer types assigning to '__global int **' from '__global float **'}}
+  gg = (__global int * __private *)gg_f;
+
+  l = g;     // expected-error {{assigning '__global int *' to '__local int *' changes address space of pointer}}
+  l = gg;    // expected-error {{assigning '__global int **' to '__local int *' changes address space of pointer}}
+  l = ll;    // expected-error {{assigning '__local int **' to '__local int *' changes address space of pointer}}
+  l = gg_f;  // expected-error {{assigning '__global float **' to '__local int *' changes address space of pointer}}
+  l = (__local int *)gg_f; // expected-error {{casting '__global float **' to type '__local int *' changes address space of pointer}}
+
+  ll = g;    // expected-error {{assigning '__global int *' to '__local int **' changes address space of pointer}}
+  ll = gg;   // expected-error {{assigning '__global int **' to '__local int **' changes address space of nested pointer}}
+  ll = l;    // expected-error {{assigning '__local int *' to '__local int **' changes address space of pointer}}
+  ll = gg_f; // expected-error {{assigning '__global float **' to '__local int **' changes address space of nested pointer}}
+  ll = (__local int * __private *)gg_f; // expected-warning {{casting '__global float **' to type '__local int **' discards qualifiers in nested pointer types}}
+
+  gg_f = g;  // expected-error {{assigning '__global int *' to '__global float **' changes address space of pointer}}
+  gg_f = gg; // expected-warning {{incompatible pointer types assigning to '__global float **' from '__global int **'}}
+  gg_f = l;  // expected-error {{assigning '__local int *' to '__global float **' changes address space of pointer}}
+  gg_f = ll; // expected-error {{assigning '__local int **' to '__global float **' changes address space of nested pointer}}
+  gg_f = (__global float * __private *)gg;
+
+  // FIXME: This doesn't seem right. This should be an error, not a warning.
+  __local int * __global * __private * lll;
+  lll = gg; // expected-warning {{incompatible pointer types assigning to '__local int *__global **' from '__global int **'}}
+
+  typedef __local int * l_t;
+  typedef __global int * g_t;
+  __private l_t * pl;
+  __private g_t * pg;
+  gg = pl;  // expected-error {{assigning 'l_t *' (aka '__local int **') to '__global int **' changes address space of nested pointer}}
+  pl = gg;  // expected-error {{assigning '__global int **' to 'l_t *' (aka '__local int **') changes address space of nested pointer}}
+  gg = pg;
+  pg = gg;
+  pg = pl;  // expected-error {{assigning 'l_t *' (aka '__local int **') to 'g_t *' (aka '__global int **') changes address space of nested pointer}}
+  pl = pg;  // expected-error {{assigning 'g_t *' (aka '__global int **') to 'l_t *' (aka '__local int **') changes address space of nested pointer}}
+
+  ll = (__local int * __private *)(void *)gg;
+  void *vp = ll;
+}
+#else
+void nested(__global int *g, __global int * __private *gg, __local int *l, __local int * __private *ll, __global float * __private *gg_f) {
+  g = gg;    // expected-error {{assigning to '__global int *' from incompatible type '__global int **'}}
+  g = l;     // expected-error {{assigning to '__global int *' from incompatible type '__local int *'}}
+  g = ll;    // expected-error {{assigning to '__global int *' from incompatible type '__local int **'}}
+  g = gg_f;  // expected-error {{assigning to '__global int *' from incompatible type '__global float **'}}
+  g = (__global int *)gg_f; // expected-error {{C-style cast from '__global float **' to '__global int *' converts between mismatching address spaces}}
+
+  gg = g;    // expected-error {{assigning to '__global int **' from incompatible type '__global int *'; take the address with &}}
+  gg = l;    // expected-error {{assigning to '__global int **' from incompatible type '__local int *'}}
+  gg = ll;   // expected-error {{assigning to '__global int **' from incompatible type '__local int **'}}
+  gg = gg_f; // expected-error {{assigning to '__global int **' from incompatible type '__global float **'}}
+  gg = (__global int * __private *)gg_f;
+
+  l = g;     // expected-error {{assigning to '__local int *' from incompatible type '__global int *'}}
+  l = gg;    // expected-error {{assigning to '__local int *' from incompatible type '__global int **'}}
+  l = ll;    // expected-error {{assigning to '__local int *' from incompatible type '__local int **'}}
+  l = gg_f;  // expected-error {{assigning to '__local int *' from incompatible type '__global float **'}}
+  l = (__local int *)gg_f; // expected-error {{C-style cast from '__global float **' to '__local int *' converts between mismatching address spaces}}
+
+  ll = g;    // expected-error {{assigning to '__local int **' from incompatible type '__global int *'}}
+  ll = gg;   // expected-error {{assigning to '__local int **' from incompatible type '__global int **'}}
+  ll = l;    // expected-error {{assigning to '__local int **' from incompatible type '__local int *'; take the address with &}}
+  ll = gg_f; // expected-error {{assigning to '__local int **' from incompatible type '__global float **'}}
+  // FIXME: The below becomes a reinterpret_cast, and therefore does not emit an error
+  // even though the address space mismatches in the nested pointers.
+  ll = (__local int * __private *)gg;
+
+  gg_f = g;  // expected-error {{assigning to '__global float **' from incompatible type '__global int *'}}
+  gg_f = gg; // expected-error {{assigning to '__global float **' from incompatible type '__global int **'}}
+  gg_f = l;  // expected-error {{assigning to '__global float **' from incompatible type '__local int *'}}
+  gg_f = ll; // expected-error {{assigning to '__global float **' from incompatible type '__local int **'}}
+  gg_f = (__global float * __private *)gg;
+
+  typedef __local int * l_t;
+  typedef __global int * g_t;
+  __private l_t * pl;
+  __private g_t * pg;
+  gg = pl;  // expected-error {{assigning to '__global int **' from incompatible type 'l_t *' (aka '__local int **')}}
+  pl = gg;  // expected-error {{assigning to 'l_t *' (aka '__local int **') from incompatible type '__global int **'}}
+  gg = pg;
+  pg = gg;
+  pg = pl;  // expected-error {{assigning to 'g_t *' (aka '__global int **') from incompatible type 'l_t *' (aka '__local int **')}}
+  pl = pg;  // expected-error {{assigning to 'l_t *' (aka '__local int **') from incompatible type 'g_t *' (aka '__global int **')}}
+
+  ll = (__local int * __private *)(void *)gg;
+  void *vp = ll;
+}
+#endif
+
 __private int func_return_priv(void);       //expected-error {{return value cannot be qualified with address space}}
 __global int func_return_global(void);      //expected-error {{return value cannot be qualified with address space}}
 __local int func_return_local(void);        //expected-error {{return value cannot be qualified with address space}}
diff --git a/test/SemaOpenCL/event_t_overload.cl b/test/SemaOpenCL/event_t_overload.cl
index 0bc67c13c7..eaf05a0489 100644
--- a/test/SemaOpenCL/event_t_overload.cl
+++ b/test/SemaOpenCL/event_t_overload.cl
@@ -7,5 +7,5 @@ void kernel ker(__local char *src1, __local float *src2, __global int *src3) {
   event_t evt;
   foo(evt, src1);
   foo(0, src2);
-  foo(evt, src3); // expected-error {{call to 'foo' is ambiguous}}
+  foo(evt, src3); // expected-error {{no matching function for call to 'foo'}}
 }
diff --git a/test/SemaOpenCL/numbered-address-space.cl b/test/SemaOpenCL/numbered-address-space.cl
index 423d03274c..8a24b3ce97 100644
--- a/test/SemaOpenCL/numbered-address-space.cl
+++ b/test/SemaOpenCL/numbered-address-space.cl
@@ -26,6 +26,6 @@ void test_generic_as_to_builtin_parameter_explicit_cast_numeric(__attribute__((a
 
 void test_generic_as_to_builtin_parameterimplicit_cast_numeric(__attribute__((address_space(3))) int *as3_ptr, float src) {
   generic int* generic_ptr = as3_ptr;
-  volatile float result = __builtin_amdgcn_ds_fmaxf(generic_ptr, src, 0, 0, false); // expected-warning {{incompatible pointer types passing '__generic int *' to parameter of type '__local float *'}}
+  volatile float result = __builtin_amdgcn_ds_fmaxf(generic_ptr, src, 0, 0, false); // expected-error {{passing '__generic int *' to parameter of type '__local float *' changes address space of pointer}}
 }
 
diff --git a/test/SemaOpenCL/queue_t_overload.cl b/test/SemaOpenCL/queue_t_overload.cl
index 0048895ac8..bc3b241bbe 100644
--- a/test/SemaOpenCL/queue_t_overload.cl
+++ b/test/SemaOpenCL/queue_t_overload.cl
@@ -7,6 +7,6 @@ void kernel ker(__local char *src1, __local float *src2, __global int *src3) {
   queue_t q;
   foo(q, src1);
   foo(0, src2);
-  foo(q, src3); // expected-error {{call to 'foo' is ambiguous}}
+  foo(q, src3); // expected-error {{no matching function for call to 'foo'}}
   foo(1, src3); // expected-error {{no matching function for call to 'foo'}}
 }