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Rein ubsan's vptr sanitizer back a bit. Per core issue 453, binding a reference 

to an object outside its lifetime does not have undefined behavior.

llvm-svn: 170387
This commit is contained in:
Richard Smith 2012-12-18 00:22:45 +00:00
parent 43b1e13386
commit be024a8150
2 changed files with 19 additions and 8 deletions
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9
clang/lib/CodeGen/CGExpr.cpp
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@ -538,8 +538,15 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
// If possible, check that the vptr indicates that there is a subobject of // If possible, check that the vptr indicates that there is a subobject of
// type Ty at offset zero within this object. // type Ty at offset zero within this object.
//
// C++11 [basic.life]p5,6:
// [For storage which does not refer to an object within its lifetime]
// The program has undefined behavior if:
// -- the [pointer or glvalue] is used to access a non-static data member
// or call a non-stastic member function
CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
if (getLangOpts().SanitizeVptr && TCK != TCK_ConstructorCall && if (getLangOpts().SanitizeVptr &&
(TCK == TCK_MemberAccess || TCK == TCK_MemberCall) &&
RD && RD->hasDefinition() && RD->isDynamicClass()) { RD && RD->hasDefinition() && RD->isDynamicClass()) {
// Compute a hash of the mangled name of the type. // Compute a hash of the mangled name of the type.
// //

18
clang/test/CodeGenCXX/catch-undef-behavior.cpp
View File

@ -1,7 +1,13 @@
// RUN: %clang_cc1 -fsanitize=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift,unreachable,return,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s // RUN: %clang_cc1 -fsanitize=signed-integer-overflow,integer-divide-by-zero,float-divide-by-zero,shift,unreachable,return,vla-bound,alignment,null,vptr,object-size,float-cast-overflow,bool,enum -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
struct S {
double d;
int a, b;
virtual int f();
};
// CHECK: @_Z17reference_binding // CHECK: @_Z17reference_binding
void reference_binding(int *p) { void reference_binding(int *p, S *q) {
// C++ core issue 453: If an lvalue to which a reference is directly bound // C++ core issue 453: If an lvalue to which a reference is directly bound
// designates neither an existing object or function of an appropriate type, // designates neither an existing object or function of an appropriate type,
// nor a region of storage of suitable size and alignment to contain an object // nor a region of storage of suitable size and alignment to contain an object
@ -16,13 +22,11 @@ void reference_binding(int *p) {
// CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 3 // CHECK-NEXT: %[[MISALIGN:.*]] = and i64 %[[PTRINT]], 3
// CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0 // CHECK-NEXT: icmp eq i64 %[[MISALIGN]], 0
int &r = *p; int &r = *p;
}
struct S { // A reference is not required to refer to an object within its lifetime.
double d; // CHECK-NOT: __ubsan_handle_dynamic_type_cache_miss
int a, b; S &r2 = *q;
virtual int f(); }
};
// CHECK: @_Z13member_access // CHECK: @_Z13member_access
void member_access(S *p) { void member_access(S *p) {