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...that had been introduced with (since reverted)
https://github.com/llvm/llvm-project/commit/886715af962de2c92fac4bd37104450345711e4a
"[clang] Introduce -fstrict-flex-arrays=<n> for stricter handling of flexible
arrays", and caused issues in the wild:
For one, the HarfBuzz project has various "fake" flexible array members of the
form
Type arrayZ[HB_VAR_ARRAY];
in https://github.com/harfbuzz/harfbuzz/blob/main/src/hb-open-type.hh, where
`HB_VAR_ARRAY` is a macro defined as
#ifndef HB_VAR_ARRAY
#define HB_VAR_ARRAY 1
#endif
in https://github.com/harfbuzz/harfbuzz/blob/main/src/hb-machinery.hh.
For another, the Firebird project in
https://github.com/FirebirdSQL/firebird/blob/master/src/lock/lock_proto.h uses
a trailing member
srq lhb_hash[1]; // Hash table
as a "fake" flexible array, but declared in a
struct lhb : public Firebird::MemoryHeader
that is not a standard-layout class (because the `Firebird::MemoryHeader` base
class also declares non-static data members).
(Checking for the second case required changing the test file from C to C++.)
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D128783
Files:
clang/test/CodeGen/bounds-checking-fam.c
clang/test/CodeGen/bounds-checking-fam.cpp
Index: clang/test/CodeGen/bounds-checking-fam.cpp
===================================================================
--- clang/test/CodeGen/bounds-checking-fam.cpp
+++ clang/test/CodeGen/bounds-checking-fam.cpp
@@ -14,21 +14,43 @@
struct Three {
int a[3];
};
+#define FLEXIBLE 1
+struct Macro {
+ int a[FLEXIBLE];
+};
+struct Base {
+ int b;
+};
+struct NoStandardLayout : Base {
+ int a[1];
+};
-// CHECK-LABEL: define {{.*}} @test_one(
-int test_one(struct One *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_one{{.*}}(
+int test_one(One *p, int i) {
// CHECK-STRICT-0-NOT: @__ubsan
return p->a[i] + (p->a)[i];
}
-// CHECK-LABEL: define {{.*}} @test_two(
-int test_two(struct Two *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_two{{.*}}(
+int test_two(Two *p, int i) {
// CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
return p->a[i] + (p->a)[i];
}
-// CHECK-LABEL: define {{.*}} @test_three(
-int test_three(struct Three *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_three{{.*}}(
+int test_three(Three *p, int i) {
// CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
return p->a[i] + (p->a)[i];
}
+
+// CHECK-LABEL: define {{.*}} @{{.*}}test_macro{{.*}}(
+int test_macro(Macro *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ return p->a[i] + (p->a)[i];
+}
+
+// CHECK-LABEL: define {{.*}} @{{.*}}test_nostandardlayout{{.*}}(
+int test_nostandardlayout(NoStandardLayout *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ return p->a[i] + (p->a)[i];
+}
Index: clang/test/CodeGen/bounds-checking-fam.cpp
===================================================================
--- clang/test/CodeGen/bounds-checking-fam.cpp
+++ clang/test/CodeGen/bounds-checking-fam.cpp
@@ -14,21 +14,43 @@
struct Three {
int a[3];
};
+#define FLEXIBLE 1
+struct Macro {
+ int a[FLEXIBLE];
+};
+struct Base {
+ int b;
+};
+struct NoStandardLayout : Base {
+ int a[1];
+};
-// CHECK-LABEL: define {{.*}} @test_one(
-int test_one(struct One *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_one{{.*}}(
+int test_one(One *p, int i) {
// CHECK-STRICT-0-NOT: @__ubsan
return p->a[i] + (p->a)[i];
}
-// CHECK-LABEL: define {{.*}} @test_two(
-int test_two(struct Two *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_two{{.*}}(
+int test_two(Two *p, int i) {
// CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
return p->a[i] + (p->a)[i];
}
-// CHECK-LABEL: define {{.*}} @test_three(
-int test_three(struct Three *p, int i) {
+// CHECK-LABEL: define {{.*}} @{{.*}}test_three{{.*}}(
+int test_three(Three *p, int i) {
// CHECK-STRICT-0: call void @__ubsan_handle_out_of_bounds_abort(
return p->a[i] + (p->a)[i];
}
+
+// CHECK-LABEL: define {{.*}} @{{.*}}test_macro{{.*}}(
+int test_macro(Macro *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ return p->a[i] + (p->a)[i];
+}
+
+// CHECK-LABEL: define {{.*}} @{{.*}}test_nostandardlayout{{.*}}(
+int test_nostandardlayout(NoStandardLayout *p, int i) {
+ // CHECK-STRICT-0-NOT: @__ubsan
+ return p->a[i] + (p->a)[i];
+}
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