Fix TBAA representation for zero-sized fields and unnamed bit-fields.

Unnamed bit-fields should not be represented in the TBAA metadata
because they do not represent storage fields (they only affect layout).

Zero-sized fields should not be represented in the TBAA metadata
because by definition they have no associated storage (so we will never
emit a load or store through them), and they might not appear in
declaration order within the struct layout.

Fixes a verifier failure when emitting a TBAA-enabled load through a
class type containing a zero-sized field.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@364140 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CodeGenTBAA.cpp b/lib/CodeGen/CodeGenTBAA.cpp
index a41cfcee4c2c299144c2b0b8782c7f0fae729c36..09de9591de7eac56bc6863bfc1e5f794a5419555 100644 (file)
--- a/lib/CodeGen/CodeGenTBAA.cpp
+++ b/lib/CodeGen/CodeGenTBAA.cpp
@@ -257,6 +257,8 @@ CodeGenTBAA::CollectFields(uint64_t BaseOffset,
     unsigned idx = 0;
     for (RecordDecl::field_iterator i = RD->field_begin(),
          e = RD->field_end(); i != e; ++i, ++idx) {
+      if ((*i)->isZeroSize(Context) || (*i)->isUnnamedBitfield())
+        continue;
       uint64_t Offset = BaseOffset +
                         Layout.getFieldOffset(idx) / Context.getCharWidth();
       QualType FieldQTy = i->getType();
@@ -297,6 +299,8 @@ llvm::MDNode *CodeGenTBAA::getBaseTypeInfoHelper(const Type *Ty) {
     const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
     SmallVector<llvm::MDBuilder::TBAAStructField, 4> Fields;
     for (FieldDecl *Field : RD->fields()) {
+      if (Field->isZeroSize(Context) || Field->isUnnamedBitfield())
+        continue;
       QualType FieldQTy = Field->getType();
       llvm::MDNode *TypeNode = isValidBaseType(FieldQTy) ?
           getBaseTypeInfo(FieldQTy) : getTypeInfo(FieldQTy);

diff --git a/test/CodeGen/tbaa-struct.cpp b/test/CodeGen/tbaa-struct.cpp
index 9e5429b2e3605ff2a5a61147b464ecf70e4aafcd..670584e3f876a4999a890d5964d3fe4d99446c47 100644 (file)
--- a/test/CodeGen/tbaa-struct.cpp
+++ b/test/CodeGen/tbaa-struct.cpp
@@ -111,8 +111,8 @@ void copy7(A *a1, AA *a2) {
 // CHECK-OLD: [[TS2]] = !{i64 0, i64 1, !{{.*}}, i64 4, i64 2, !{{.*}}, i64 8, i64 4, !{{.*}}, i64 12, i64 1, !{{.*}}, i64 16, i64 4, {{.*}}, i64 20, i64 4, {{.*}}}
 // (offset, size) = (0,8) char; (0,2) char; (4,8) char
 // CHECK-OLD: [[TS3]] = !{i64 0, i64 8, !{{.*}}, i64 0, i64 2, !{{.*}}, i64 4, i64 8, !{{.*}}}
-// CHECK-OLD: [[TS4]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 4, [[TAG_INT]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]]}
-// CHECK-OLD: [[TS5]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 4, i64 4, [[TAG_INT]], i64 4, i64 1, [[TAG_CHAR]], i64 5, i64 1, [[TAG_CHAR]]}
+// CHECK-OLD: [[TS4]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 1, i64 1, [[TAG_CHAR]], i64 2, i64 1, [[TAG_CHAR]]}
+// CHECK-OLD: [[TS5]] = !{i64 0, i64 1, [[TAG_CHAR]], i64 4, i64 1, [[TAG_CHAR]], i64 5, i64 1, [[TAG_CHAR]]}
 
 // CHECK-NEW-DAG: [[TYPE_char:!.*]] = !{{{.*}}, i64 1, !"omnipotent char"}
 // CHECK-NEW-DAG: [[TAG_char]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 0}
@@ -123,7 +123,7 @@ void copy7(A *a1, AA *a2) {
 // CHECK-NEW-DAG: [[TYPE_B:!.*]] = !{[[TYPE_char]], i64 24, !"_ZTS1B", [[TYPE_char]], i64 0, i64 1, [[TYPE_A]], i64 4, i64 16, [[TYPE_int]], i64 20, i64 4}
 // CHECK-NEW-DAG: [[TAG_B]] = !{[[TYPE_B]], [[TYPE_B]], i64 0, i64 24}
 // CHECK-NEW-DAG: [[TAG_U]] = !{[[TYPE_char]], [[TYPE_char]], i64 0, i64 12}
-// CHECK-NEW-DAG: [[TYPE_C:!.*]] = !{[[TYPE_char]], i64 3, !"_ZTS1C", [[TYPE_char]], i64 0, i64 1, [[TYPE_int]], i64 1, i64 4, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1}
+// CHECK-NEW-DAG: [[TYPE_C:!.*]] = !{[[TYPE_char]], i64 3, !"_ZTS1C", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1}
 // CHECK-NEW-DAG: [[TAG_C]] = !{[[TYPE_C]], [[TYPE_C]], i64 0, i64 3}
-// CHECK-NEW-DAG: [[TYPE_D:!.*]] = !{[[TYPE_char]], i64 6, !"_ZTS1D", [[TYPE_char]], i64 0, i64 1, [[TYPE_int]], i64 4, i64 4, [[TYPE_char]], i64 4, i64 1, [[TYPE_char]], i64 5, i64 1}
+// CHECK-NEW-DAG: [[TYPE_D:!.*]] = !{[[TYPE_char]], i64 6, !"_ZTS1D", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 4, i64 1, [[TYPE_char]], i64 5, i64 1}
 // CHECK-NEW-DAG: [[TAG_D]] = !{[[TYPE_D]], [[TYPE_D]], i64 0, i64 6}

diff --git a/test/CodeGen/tbaa.cpp b/test/CodeGen/tbaa.cpp
index c8a9e69d92b99b3e79642be966a595e894a664cc..86e34f37b5e5c17029491ea732fc312375ead123 100644 (file)
--- a/test/CodeGen/tbaa.cpp
+++ b/test/CodeGen/tbaa.cpp
@@ -272,9 +272,9 @@ uint32_t g15(StructS *S, StructS3 *S3, uint64_t count) {
 // OLD-PATH: [[TAG_D_b_a_f32]] = !{[[TYPE_D:!.*]], [[TYPE_INT]], i64 12}
 // OLD-PATH: [[TYPE_D]] = !{!"_ZTS7StructD", [[TYPE_SHORT]], i64 0, [[TYPE_B]], i64 4, [[TYPE_INT]], i64 28, [[TYPE_CHAR]], i64 32}
 // OLD-PATH: [[TAG_five_b]] = !{[[TYPE_five:!.*]], [[TYPE_CHAR]], i64 1}
-// OLD-PATH: [[TYPE_five]] = !{!"_ZTS4five", [[TYPE_CHAR]], i64 0, [[TYPE_INT]], i64 1, [[TYPE_CHAR]], i64 1, [[TYPE_CHAR]], i64 2}
+// OLD-PATH: [[TYPE_five]] = !{!"_ZTS4five", [[TYPE_CHAR]], i64 0, [[TYPE_CHAR]], i64 1, [[TYPE_CHAR]], i64 2}
 // OLD-PATH: [[TAG_six_b]] = !{[[TYPE_six:!.*]], [[TYPE_CHAR]], i64 4}
-// OLD-PATH: [[TYPE_six]] = !{!"_ZTS3six", [[TYPE_CHAR]], i64 0, [[TYPE_INT]], i64 4, [[TYPE_CHAR]], i64 4, [[TYPE_CHAR]], i64 5}
+// OLD-PATH: [[TYPE_six]] = !{!"_ZTS3six", [[TYPE_CHAR]], i64 0, [[TYPE_CHAR]], i64 4, [[TYPE_CHAR]], i64 5}
 
 // NEW-PATH-DAG: [[ROOT:!.*]] = !{!"Simple C++ TBAA"}
 // NEW-PATH-DAG: [[TYPE_char:!.*]] = !{[[ROOT]], i64 1, !"omnipotent char"}
@@ -299,7 +299,7 @@ uint32_t g15(StructS *S, StructS3 *S3, uint64_t count) {
 // NEW-PATH-DAG: [[TAG_C_b_a_f32]] = !{[[TYPE_C]], [[TYPE_int]], i64 12, i64 4}
 // NEW-PATH-DAG: [[TYPE_D:!.*]] = !{[[TYPE_char]], i64 36, !"_ZTS7StructD", [[TYPE_short]], i64 0, i64 2, [[TYPE_B]], i64 4, i64 24, [[TYPE_int]], i64 28, i64 4, [[TYPE_char]], i64 32, i64 1}
 // NEW-PATH-DAG: [[TAG_D_b_a_f32]] = !{[[TYPE_D]], [[TYPE_int]], i64 12, i64 4}
-// NEW-PATH-DAG: [[TYPE_five:!.*]] = !{[[TYPE_char]], i64 3, !"_ZTS4five", [[TYPE_char]], i64 0, i64 1, [[TYPE_int]], i64 1, i64 4, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1}
+// NEW-PATH-DAG: [[TYPE_five:!.*]] = !{[[TYPE_char]], i64 3, !"_ZTS4five", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 1, i64 1, [[TYPE_char]], i64 2, i64 1}
 // NEW-PATH-DAG: [[TAG_five_b]] = !{[[TYPE_five]], [[TYPE_char]], i64 1, i64 1}
-// NEW-PATH-DAG: [[TYPE_six:!.*]] = !{[[TYPE_char]], i64 6, !"_ZTS3six", [[TYPE_char]], i64 0, i64 1, [[TYPE_int]], i64 4, i64 4, [[TYPE_char]], i64 4, i64 1, [[TYPE_char]], i64 5, i64 1}
+// NEW-PATH-DAG: [[TYPE_six:!.*]] = !{[[TYPE_char]], i64 6, !"_ZTS3six", [[TYPE_char]], i64 0, i64 1, [[TYPE_char]], i64 4, i64 1, [[TYPE_char]], i64 5, i64 1}
 // NEW-PATH-DAG: [[TAG_six_b]] = !{[[TYPE_six]], [[TYPE_char]], i64 4, i64 1}

diff --git a/test/CodeGenCXX/no-unique-address.cpp b/test/CodeGenCXX/no-unique-address.cpp
index fce5f8b819725dab22b88545341d8c5c2a27d7e3..c88fb4d2c30f614165b630c6035db7ba57de142c 100644 (file)
--- a/test/CodeGenCXX/no-unique-address.cpp
+++ b/test/CodeGenCXX/no-unique-address.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -std=c++2a %s -emit-llvm -o - -triple x86_64-linux-gnu | FileCheck %s
+// RUN: %clang_cc1 -std=c++2a %s -emit-llvm -o - -triple x86_64-linux-gnu -O2 -disable-llvm-passes | FileCheck %s --check-prefix=CHECK-OPT
 
 struct A { ~A(); int n; char c[3]; };
 struct B { [[no_unique_address]] A a; char k; };
@@ -77,3 +78,18 @@ Empty1 &accessE1(FieldOverlap &fo) { return fo.e1; }
 // CHECK: %[[RET:.*]] = bitcast i8* %[[ADJUSTED]] to %[[E1]]*
 // CHECK: ret %[[E1]]* %[[RET]]
 Empty1 &accessE2(FieldOverlap &fo) { return fo.e2; }
+
+struct LaterDeclaredFieldHasLowerOffset {
+  int a;
+  int b;
+  [[no_unique_address]] Empty1 e;
+};
+// CHECK-OPT-LABEL: @_Z41loadWhereLaterDeclaredFieldHasLowerOffset
+int loadWhereLaterDeclaredFieldHasLowerOffset(LaterDeclaredFieldHasLowerOffset &a) {
+  // CHECK-OPT: getelementptr
+  // CHECK-OPT: load {{.*}}, !tbaa ![[TBAA_AB:[0-9]*]]
+  return a.b;
+}
+// Note, never emit TBAA for zero-size fields.
+// CHECK-OPT: ![[TBAA_AB]] = !{![[TBAA_A:[0-9]*]], ![[TBAA_INT:[0-9]*]], i64 4}
+// CHECK-OPT: ![[TBAA_A]] = !{!"_ZTS32LaterDeclaredFieldHasLowerOffset", ![[TBAA_INT]], i64 0, ![[TBAA_INT]], i64 4}