[PATCH] D41399: [CodeGen] Represent array members in new-format TBAA type descriptors

[Ivan Kosarev via Phabricator via cfe-commits]

kosarev created this revision.
kosarev added reviewers: rjmccall, hfinkel.
kosarev added a project: clang.

Now that in the new TBAA format we allow access types to be of any object types, including aggregate ones, it becomes critical to specify types of all sub-objects such aggregates comprise as their members. In order to meet this requirement, this patch enables generation of field descriptors for members of array types.

This patch requires https://reviews.llvm.org/D41394 to be landed first.


Repository:
  rL LLVM

https://reviews.llvm.org/D41399

Files:
  lib/CodeGen/CodeGenTBAA.cpp
  test/CodeGen/tbaa-array.cpp


Index: test/CodeGen/tbaa-array.cpp
===================================================================
--- test/CodeGen/tbaa-array.cpp
+++ test/CodeGen/tbaa-array.cpp
@@ -1,18 +1,28 @@
 // RUN: %clang_cc1 -triple x86_64-linux -O1 -disable-llvm-passes %s \
-// RUN:     -emit-llvm -o - | FileCheck %s
-//
-// Check that we generate correct TBAA information for accesses to array
-// elements.
+// RUN:     -new-struct-path-tbaa -emit-llvm -o - | FileCheck %s
 
 struct A { int i; };
 struct B { A a[1]; };
+struct C { int i; int x[3]; };
 
+// Check that we generate correct TBAA information for accesses to array
+// elements.
 int foo(B *b) {
 // CHECK-LABEL: _Z3fooP1B
 // CHECK: load i32, {{.*}}, !tbaa [[TAG_A_i:!.*]]
   return b->a->i;
 }
 
-// CHECK-DAG: [[TAG_A_i]] = !{[[TYPE_A:!.*]], [[TYPE_int:!.*]], i64 0}
-// CHECK-DAG: [[TYPE_A]] = !{!"_ZTS1A", !{{.*}}, i64 0}
-// CHECK-DAG: [[TYPE_int]] = !{!"int", !{{.*}}, i64 0}
+// Check that members of array types are represented correctly.
+int bar(C *c) {
+// CHECK-LABEL: _Z3barP1C
+// CHECK: load i32, {{.*}}, !tbaa [[TAG_C_i:!.*]]
+  return c->i;
+}
+
+// CHECK-DAG: [[TAG_A_i]] = !{[[TYPE_A:!.*]], [[TYPE_int:!.*]], i64 0, i64 4}
+// CHECK-DAG: [[TAG_C_i]] = !{[[TYPE_C:!.*]], [[TYPE_int:!.*]], i64 0, i64 16}
+// CHECK-DAG: [[TYPE_A]] = !{[[TYPE_char:!.*]], i64 4, !"_ZTS1A", [[TYPE_int]], i64 0, i64 4}
+// CHECK-DAG: [[TYPE_C]] = !{[[TYPE_char]], i64 16, !"_ZTS1C", [[TYPE_int]], i64 0, i64 4, [[TYPE_int]], i64 4, i64 12}
+// CHECK-DAG: [[TYPE_int]] = !{[[TYPE_char]], i64 4, !"int"}
+// CHECK-DAG: [[TYPE_char]] = !{{{!.*}}, i64 1, !"omnipotent char"}
Index: lib/CodeGen/CodeGenTBAA.cpp
===================================================================
--- lib/CodeGen/CodeGenTBAA.cpp
+++ lib/CodeGen/CodeGenTBAA.cpp
@@ -161,6 +161,10 @@
   if (Ty->isPointerType() || Ty->isReferenceType())
     return createScalarTypeNode("any pointer", getChar(), Size);
 
+  // Accesses to arrays are accesses to objects of their element types.
+  if (CodeGenOpts.NewStructPathTBAA && Ty->isArrayType())
+    return getTypeInfo(cast<ArrayType>(Ty)->getElementType());
+
   // Enum types are distinct types. In C++ they have "underlying types",
   // however they aren't related for TBAA.
   if (const EnumType *ETy = dyn_cast<EnumType>(Ty)) {


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