maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[CodeGen][MSan] Don't use offsets of zero-sized fields 

Such fields will likely have offset zero making
__sanitizer_dtor_callback poisoning wrong regions.
E.g. it can poison base class member from derived class constructor.

Differential Revision: https://reviews.llvm.org/D92727
This commit is contained in:
Vitaly Buka 2020-12-04 23:47:11 -08:00
parent c102c783cd
commit 3e1cb0db8a
2 changed files with 19 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
clang/lib/CodeGen/CGClass.cpp
View File

@ -1700,12 +1700,23 @@ namespace {
return FieldHasTrivialDestructorBody(Context, F);
};
auto IsZeroSize = [&](const FieldDecl *F) {
return F->isZeroSize(Context);
};
// Poison blocks of fields with trivial destructors making sure that block
// begin and end do not point to zero-sized fields. They don't have
// correct offsets so can't be used to calculate poisoning range.
for (auto It = Fields.begin(); It != Fields.end();) {
It = std::find_if(It, Fields.end(), IsTrivial);
It = std::find_if(It, Fields.end(), [&](const FieldDecl *F) {
return IsTrivial(F) && !IsZeroSize(F);
});
if (It == Fields.end())
break;
auto Start = It++;
It = std::find_if_not(It, Fields.end(), IsTrivial);
It = std::find_if(It, Fields.end(), [&](const FieldDecl *F) {
return !IsTrivial(F) && !IsZeroSize(F);
});
PoisonMembers(CGF, (*Start)->getFieldIndex(),
It == Fields.end() ? -1 : (*It)->getFieldIndex());

12
clang/test/CodeGenCXX/sanitize-dtor-zero-size-field.cpp
View File

@ -1,8 +1,6 @@
// RUN: %clang_cc1 -O0 -fsanitize=memory -fsanitize-memory-use-after-dtor -disable-llvm-passes -std=c++20 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s --implicit-check-not "call void @__sanitizer_dtor_callback"
// RUN: %clang_cc1 -O1 -fsanitize=memory -fsanitize-memory-use-after-dtor -disable-llvm-passes -std=c++20 -triple=x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s --implicit-check-not "call void @__sanitizer_dtor_callback"
// This test convers invalid behaviour which will be fixed in followup patches.
struct Empty {};
struct EmptyNonTrivial {
@ -115,7 +113,7 @@ struct Struct {
static_assert(sizeof(Struct) == 24);
} // namespace T6
// CHECK-LABEL: define {{.*}} @_ZN5empty2T66StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 21)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 13)
// CHECK-NEXT: ret void
namespace T7 {
@ -130,7 +128,7 @@ static_assert(sizeof(Struct) == 24);
} // namespace T7
// CHECK-LABEL: define {{.*}} @_ZN5empty2T76StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 8)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 21)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 5)
// CHECK-NEXT: ret void
namespace T8 {
@ -160,7 +158,7 @@ static_assert(sizeof(Struct) == 24);
} // namespace T9
// CHECK-LABEL: define {{.*}} @_ZN5empty2T96StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 12)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 21)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 1)
// CHECK-NEXT: ret void
namespace T10 {
@ -190,7 +188,6 @@ static_assert(sizeof(Struct) == 24);
} // namespace T11
// CHECK-LABEL: define {{.*}} @_ZN5empty3T116StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 16)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 24)
// CHECK-NEXT: ret void
namespace T12 {
@ -317,6 +314,7 @@ struct Struct {
static_assert(sizeof(Struct) == 24);
} // namespace T8
// CHECK-LABEL: define {{.*}} @_ZN17empty_non_trivial2T86StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 8)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 5)
// CHECK-NEXT: ret void
@ -346,6 +344,7 @@ struct Struct {
static_assert(sizeof(Struct) == 24);
} // namespace T10
// CHECK-LABEL: define {{.*}} @_ZN17empty_non_trivial3T106StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 12)
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 1)
// CHECK-NEXT: ret void
@ -375,4 +374,5 @@ static_assert(sizeof(Struct) == 24);
} // namespace T12
} // namespace empty_non_trivial
// CHECK-LABEL: define {{.*}} @_ZN17empty_non_trivial3T126StructD2Ev(
// CHECK: call void @__sanitizer_dtor_callback(i8* {{.*}}, i64 16)
// CHECK: ret void