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[Clang][kcfi] Sign extend KCFI typeid rather than zero extend #136734

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[Clang][kcfi] Sign extend KCFI typeid rather than zero extend #136734

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2 changes: 1 addition & 1 deletion clang/lib/CodeGen/CodeGenModule.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2931,7 +2931,7 @@ void CodeGenModule::finalizeKCFITypes() {
continue;

std::string Asm = (".weak __kcfi_typeid_" + Name + "\n.set __kcfi_typeid_" +
Name + ", " + Twine(Type->getZExtValue()) + "\n")
Name + ", " + Twine(Type->getSExtValue()) + "\n")
.str();
M.appendModuleInlineAsm(Asm);
}
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82 changes: 56 additions & 26 deletions clang/test/CodeGen/kcfi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,45 +8,79 @@
/// Must emit __kcfi_typeid symbols for address-taken function declarations
// CHECK: module asm ".weak __kcfi_typeid_[[F4:[a-zA-Z0-9_]+]]"
// CHECK: module asm ".set __kcfi_typeid_[[F4]], [[#%d,HASH:]]"
// CHECK: module asm ".weak __kcfi_typeid_[[F4_ARG:[a-zA-Z0-9_]+]]"
// CHECK: module asm ".set __kcfi_typeid_[[F4_ARG]], [[#%d,ARG_HASH:]]"

/// Must not __kcfi_typeid symbols for non-address-taken declarations
// CHECK-NOT: module asm ".weak __kcfi_typeid_{{f6|_Z2f6v}}"

// C: @ifunc1 = ifunc i32 (i32), ptr @resolver1
// C: @ifunc2 = ifunc i64 (i64), ptr @resolver2
typedef int (*fn_t)(void);
typedef int (*fn_u_t)(unsigned int);

// CHECK: define dso_local{{.*}} i32 @{{f1|_Z2f1v}}(){{.*}} !kcfi_type ![[#TYPE:]]
int f1(void) { return 0; }
int f1(void);

// CHECK: define dso_local{{.*}} i32 @{{f2|_Z2f2v}}(){{.*}} !kcfi_type ![[#TYPE2:]]
unsigned int f2(void) { return 2; }
unsigned int f2(void);

static int f3(void);

extern int f4(void);
extern int f4_arg(unsigned int);

// CHECK-LABEL: define dso_local{{.*}} i32 @{{__call|_Z6__callPFivE}}(ptr{{.*}} %f)
int __call(fn_t f) __attribute__((__no_sanitize__("kcfi"))) {
// CHECK-NOT: call{{.*}} i32 %{{.}}(){{.*}} [ "kcfi"
return f();
}

// CHECK: define dso_local{{.*}} i32 @{{call|_Z4callPFivE}}(ptr{{.*}} %f){{.*}}
// CHECK-LABEL: define dso_local{{.*}} i32 @{{call|_Z4callPFivE}}(ptr{{.*}} %f)
int call(fn_t f) {
// CHECK: call{{.*}} i32 %{{.}}(){{.*}} [ "kcfi"(i32 [[#HASH]]) ]
return f();
}

// CHECK-DAG: define internal{{.*}} i32 @{{f3|_ZL2f3v}}(){{.*}} !kcfi_type ![[#TYPE]]
// CHECK-LABEL: define dso_local{{.*}} i32 @{{call_with_arg|_Z13call_with_argPFijE}}(ptr{{.*}} %f)
int call_with_arg(fn_u_t f) {
// CHECK: call{{.*}} i32 %0(i32 {{.*}}) [ "kcfi"(i32 [[#ARG_HASH]]) ]
return f(42);
}

static int f5(void);

extern int f6(void);

int test(void) {
return call(f1) +
__call((fn_t)f2) +
call(f3) +
call(f4) +
call_with_arg(f4_arg) +
f5() +
f6();
}

// CHECK-LABEL: define dso_local{{.*}} i32 @{{f1|_Z2f1v}}(){{.*}} !kcfi_type ![[#TYPE:]]
int f1(void) { return 0; }

// CHECK-LABEL: define dso_local{{.*}} i32 @{{f2|_Z2f2v}}(){{.*}} !kcfi_type ![[#TYPE2:]]
unsigned int f2(void) { return 2; }

// CHECK: define internal{{.*}} i32 @{{f3|_ZL2f3v}}(){{.*}} !kcfi_type ![[#TYPE]]
static int f3(void) { return 1; }

// CHECK-DAG: declare !kcfi_type ![[#TYPE]]{{.*}} i32 @[[F4]]()
extern int f4(void);
// CHECK-LABEL: declare !kcfi_type
// CHECK-SAME: ![[#TYPE]]{{.*}} i32 @[[F4]]
// CHECK-LABEL: declare !kcfi_type
// CHECK-SAME: ![[#ARG_TYPE:]]{{.*}} i32 @[[F4_ARG]]

/// Must not emit !kcfi_type for non-address-taken local functions
// CHECK: define internal{{.*}} i32 @{{f5|_ZL2f5v}}()
// CHECK-NOT: !kcfi_type
// CHECK-SAME: {
static int f5(void) { return 2; }

// CHECK-DAG: declare !kcfi_type ![[#TYPE]]{{.*}} i32 @{{f6|_Z2f6v}}()
extern int f6(void);
// CHECK: declare !kcfi_type ![[#TYPE]]{{.*}} i32 @{{f6|_Z2f6v}}()

#ifndef __cplusplus
// C: define internal ptr @resolver1() #[[#]] !kcfi_type ![[#]] {
Expand All @@ -58,30 +92,26 @@ static void *resolver2(void) { return 0; }
long ifunc2(long) __attribute__((ifunc("resolver2")));
#endif

int test(void) {
return call(f1) +
__call((fn_t)f2) +
call(f3) +
call(f4) +
f5() +
f6();
}

#ifdef __cplusplus
struct A {
// MEMBER-DAG: define{{.*}} void @_ZN1A1fEv(ptr{{.*}} %this){{.*}} !kcfi_type ![[#TYPE3:]]
void f() {}
};

void test_member_call(void) {
void (A::* p)() = &A::f;
// MEMBER-DAG: call void %[[#]](ptr{{.*}} [ "kcfi"(i32 [[#%d,HASH3:]]) ]
// MEMBER: call void %[[#]](ptr{{.*}} [ "kcfi"(i32 [[#%d,HASH3:]]) ]
(A().*p)();
}

// MEMBER: define{{.*}} void @_ZN1A1fEv(ptr{{.*}} %this){{.*}} !kcfi_type ![[#TYPE3:]]
#endif

// CHECK-DAG: ![[#]] = !{i32 4, !"kcfi", i32 1}
// OFFSET-DAG: ![[#]] = !{i32 4, !"kcfi-offset", i32 3}
// CHECK-DAG: ![[#TYPE]] = !{i32 [[#HASH]]}
// CHECK-DAG: ![[#TYPE2]] = !{i32 [[#%d,HASH2:]]}
// MEMBER-DAG: ![[#TYPE3]] = !{i32 [[#HASH3]]}
// CHECK: ![[#]] = !{i32 4, !"kcfi", i32 1}
//
// OFFSET: ![[#]] = !{i32 4, !"kcfi-offset", i32 3}
//
// CHECK: ![[#TYPE]] = !{i32 [[#HASH]]}
// CHECK: ![[#TYPE2]] = !{i32 [[#%d,HASH2:]]}
// CHECK: ![[#ARG_TYPE]] = !{i32 [[#ARG_HASH]]}
//
// MEMBER: ![[#TYPE3]] = !{i32 [[#HASH3]]}
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