[CodeGen] Fix generation of TBAA tags for may-alias accesses

This patch fixes creating TBAA access descriptors for
may_alias-marked access types. Currently, for such types we
generate ordinary descriptors with char as its access type. The
patch changes this to produce proper may-alias descriptors.

Differential Revision: https://reviews.llvm.org/D42366

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@325575 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 33cf0bc9571e01b4493b38ff82c5af39edb3c24a..f21d40671cf756bcea3b42b29aadfb2bb562f5ad 100644 (file)
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -602,13 +602,9 @@ llvm::MDNode *CodeGenModule::getTBAATypeInfo(QualType QTy) {
 }
 
 TBAAAccessInfo CodeGenModule::getTBAAAccessInfo(QualType AccessType) {
-  // Pointee values may have incomplete types, but they shall never be
-  // dereferenced.
-  if (AccessType->isIncompleteType())
-    return TBAAAccessInfo::getIncompleteInfo();
-
-  uint64_t Size = Context.getTypeSizeInChars(AccessType).getQuantity();
-  return TBAAAccessInfo(getTBAATypeInfo(AccessType), Size);
+  if (!TBAA)
+    return TBAAAccessInfo();
+  return TBAA->getAccessInfo(AccessType);
 }
 
 TBAAAccessInfo

diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index 90509b0d29cbbebc177bbd7e5b52cc88c7db3cb8..ec48231e5247e00c7b571e6ad7f58bb4d6bdd4ee 100644 (file)
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -215,6 +215,19 @@ llvm::MDNode *CodeGenTBAA::getTypeInfo(QualType QTy) {
   return MetadataCache[Ty] = TypeNode;
 }
 
+TBAAAccessInfo CodeGenTBAA::getAccessInfo(QualType AccessType) {
+  // Pointee values may have incomplete types, but they shall never be
+  // dereferenced.
+  if (AccessType->isIncompleteType())
+    return TBAAAccessInfo::getIncompleteInfo();
+
+  if (TypeHasMayAlias(AccessType))
+    return TBAAAccessInfo::getMayAliasInfo();
+
+  uint64_t Size = Context.getTypeSizeInChars(AccessType).getQuantity();
+  return TBAAAccessInfo(getTypeInfo(AccessType), Size);
+}
+
 TBAAAccessInfo CodeGenTBAA::getVTablePtrAccessInfo(llvm::Type *VTablePtrType) {
   llvm::DataLayout DL(&Module);
   unsigned Size = DL.getPointerTypeSize(VTablePtrType);

diff --git a/lib/CodeGen/CodeGenTBAA.h b/lib/CodeGen/CodeGenTBAA.h
index c3e5c30643d10f61cd7b494cdbea8fb292059c51..86ba407c05c6f7d266f7a2e63416a90af1d2ff5c 100644 (file)
--- a/lib/CodeGen/CodeGenTBAA.h
+++ b/lib/CodeGen/CodeGenTBAA.h
@@ -177,6 +177,10 @@ public:
   /// given type.
   llvm::MDNode *getTypeInfo(QualType QTy);
 
+  /// getAccessInfo - Get TBAA information that describes an access to
+  /// an object of the given type.
+  TBAAAccessInfo getAccessInfo(QualType AccessType);
+
   /// getVTablePtrAccessInfo - Get the TBAA information that describes an
   /// access to a virtual table pointer.
   TBAAAccessInfo getVTablePtrAccessInfo(llvm::Type *VTablePtrType);

diff --git a/test/CodeGen/may-alias.c b/test/CodeGen/may-alias.c
index 41eda858706889adc550091793e38239c0bb36ec..5f72d058f84bd04b11f2c20e1123efe83b27b8d2 100644 (file)
--- a/test/CodeGen/may-alias.c
+++ b/test/CodeGen/may-alias.c
@@ -1,18 +1,24 @@
-// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 -no-struct-path-tbaa -disable-llvm-passes -o - %s | FileCheck %s
-// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 -disable-llvm-passes -o - %s | FileCheck %s -check-prefix=PATH
+// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 \
+// RUN:     -no-struct-path-tbaa -disable-llvm-passes -o - %s | \
+// RUN:     FileCheck %s -check-prefixes=CHECK,SCALAR
+// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 \
+// RUN:     -disable-llvm-passes -o - %s | \
+// RUN:     FileCheck %s -check-prefixes=CHECK,OLD-PATH
+// RUN: %clang_cc1 -Werror -triple i386-unknown-unknown -emit-llvm -O1 \
+// RUN:     -new-struct-path-tbaa -disable-llvm-passes -o - %s | \
+// RUN:     FileCheck %s -check-prefixes=CHECK,NEW-PATH
 
 // Types with the may_alias attribute should be considered equivalent
 // to char for aliasing.
 
 typedef int __attribute__((may_alias)) aliasing_int;
 
-void test0(aliasing_int *ai, int *i)
-{
-// CHECK: store i32 0, i32* %{{.*}}, !tbaa [[TAG_CHAR:!.*]]
-// PATH: store i32 0, i32* %{{.*}}, !tbaa [[TAG_CHAR:!.*]]
+void test0(aliasing_int *ai, int *i) {
+// CHECK-LABEL: test0
+// CHECK: store i32 0, {{.*}}, !tbaa [[TAG_alias_int:!.*]]
   *ai = 0;
-// CHECK: store i32 1, i32* %{{.*}}, !tbaa [[TAG_INT:!.*]]
-// PATH: store i32 1, i32* %{{.*}}, !tbaa [[TAG_INT:!.*]]
+
+// CHECK: store i32 1, {{.*}}, !tbaa [[TAG_int:!.*]]
   *i = 1;
 }
 
@@ -20,23 +26,36 @@ void test0(aliasing_int *ai, int *i)
 struct Test1 { int x; };
 struct Test1MA { int x; } __attribute__((may_alias));
 void test1(struct Test1MA *p1, struct Test1 *p2) {
-  // CHECK: store i32 2, i32* {{%.*}}, !tbaa [[TAG_CHAR]]
-  // PATH: store i32 2, i32* {{%.*}}, !tbaa [[TAG_CHAR]]
+// CHECK-LABEL: test1
+// CHECK: store i32 2, {{.*}}, !tbaa [[TAG_alias_test1_x:!.*]]
   p1->x = 2;
-  // CHECK: store i32 3, i32* {{%.*}}, !tbaa [[TAG_INT]]
-  // PATH: store i32 3, i32* {{%.*}}, !tbaa [[TAG_test1_x:!.*]]
+
+// CHECK: store i32 3, {{.*}}, !tbaa [[TAG_test1_x:!.*]]
   p2->x = 3;
 }
-// CHECK:  !"any pointer", [[TYPE_CHAR:!.*]],
-// CHECK: [[TYPE_CHAR]] = !{!"omnipotent char", [[TAG_CXX_TBAA:!.*]],
-// CHECK: [[TAG_CXX_TBAA]] = !{!"Simple C/C++ TBAA"}
-// CHECK: [[TAG_CHAR]] = !{[[TYPE_CHAR]], [[TYPE_CHAR]], i64 0}
-// CHECK: [[TAG_INT]] = !{[[TYPE_INT:!.*]], [[TYPE_INT]], i64 0}
-// CHECK: [[TYPE_INT]] = !{!"int", [[TYPE_CHAR]]
-
-// PATH: [[TYPE_CHAR:!.*]] = !{!"omnipotent char", !{{.*}}
-// PATH: [[TAG_CHAR]] = !{[[TYPE_CHAR]], [[TYPE_CHAR]], i64 0}
-// PATH: [[TAG_INT]] = !{[[TYPE_INT:!.*]], [[TYPE_INT]], i64 0}
-// PATH: [[TYPE_INT]] = !{!"int", [[TYPE_CHAR]]
-// PATH: [[TAG_test1_x]] = !{[[TYPE_test1:!.*]], [[TYPE_INT]], i64 0}
-// PATH: [[TYPE_test1]] = !{!"Test1", [[TYPE_INT]], i64 0}
+
+// SCALAR-DAG: [[ROOT:!.*]] = !{!"Simple C/C++ TBAA"}
+// SCALAR-DAG: [[TYPE_char:!.*]] = !{!"omnipotent char", [[ROOT]], i64 0}
+// SCALAR-DAG: [[TAG_alias_int]] = !{[[TYPE_char]], [[TYPE_char]], i64 0}
+// SCALAR-DAG: [[TAG_alias_test1_x]] = !{[[TYPE_char]], [[TYPE_char]], i64 0}
+// SCALAR-DAG: [[TYPE_int:!.*]] = !{!"int", [[TYPE_char]], i64 0}
+// SCALAR-DAG: [[TAG_int]] = !{[[TYPE_int]], [[TYPE_int]], i64 0}
+// SCALAR-DAG: [[TAG_test1_x]] = !{[[TYPE_int]], [[TYPE_int]], i64 0}
+
+// OLD-PATH-DAG: [[ROOT:!.*]] = !{!"Simple C/C++ TBAA"}
+// OLD-PATH-DAG: [[TYPE_char:!.*]] = !{!"omnipotent char", [[ROOT]], i64 0}
+// OLD-PATH-DAG: [[TAG_alias_int]] = !{[[TYPE_char]], [[TYPE_char]], i64 0}
+// OLD-PATH-DAG: [[TAG_alias_test1_x]] = !{[[TYPE_char]], [[TYPE_char]], i64 0}
+// OLD-PATH-DAG: [[TYPE_int:!.*]] = !{!"int", [[TYPE_char]], i64 0}
+// OLD-PATH-DAG: [[TAG_int]] = !{[[TYPE_int]], [[TYPE_int]], i64 0}
+// OLD-PATH-DAG: [[TYPE_test1:!.*]] = !{!"Test1", [[TYPE_int]], i64 0}
+// OLD-PATH-DAG: [[TAG_test1_x]] = !{[[TYPE_test1]], [[TYPE_int]], i64 0}
+
+// NEW-PATH-DAG: [[ROOT:!.*]] = !{!"Simple C/C++ TBAA"}
+// NEW-PATH-DAG: [[TYPE_char:!.*]] = !{[[ROOT]], i64 1, !"omnipotent char"}
+// NEW-PATH-DAG: [[TAG_alias_int]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0}
+// NEW-PATH-DAG: [[TAG_alias_test1_x]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0}
+// NEW-PATH-DAG: [[TYPE_int:!.*]] = !{[[TYPE_char]], i64 4, !"int"}
+// NEW-PATH-DAG: [[TAG_int]] = !{[[TYPE_int]], [[TYPE_int]], i64 0, i64 4}
+// NEW-PATH-DAG: [[TYPE_test1:!.*]] = !{[[TYPE_char]], i64 4, !"Test1", [[TYPE_int]], i64 0, i64 4}
+// NEW-PATH-DAG: [[TAG_test1_x]] = !{[[TYPE_test1]], [[TYPE_int]], i64 0, i64 4}