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llvm-project/clang/test/CodeGen/pass-object-size.c
George Burgess IV f8f6324983 [Sema] Fix PR30346: relax __builtin_object_size checks. 
This patch makes us act more conservatively when trying to determine
the objectsize for an array at the end of an object. This is in
response to code like the following:

```
struct sockaddr {
  /* snip */
  char sa_data[14];
};

void foo(const char *s) {
  size_t slen = strlen(s) + 1;
  size_t added_len = slen <= 14 ? 0 : slen - 14;
  struct sockaddr *sa = malloc(sizeof(struct sockaddr) + added_len);
  strcpy(sa->sa_data, s);
  // ...
}
```

`__builtin_object_size(sa->sa_data, 1)` would return 14, when there
could be more than 14 bytes at `sa->sa_data`.

Code like this is apparently not uncommon. FreeBSD's manual even
explicitly mentions this pattern:
https://www.freebsd.org/doc/en/books/developers-handbook/sockets-essential-functions.html
(section 7.5.1.1.2).

In light of this, we now just give up on any array at the end of an
object if we can't find the object's initial allocation.

I lack numbers for how much more conservative we actually become as a
result of this change, so I chose the fix that would make us as
compatible with GCC as possible. If we want to be more aggressive, I'm
happy to consider some kind of whitelist or something instead.

llvm-svn: 281277
2016-09-12 23:50:35 +00:00

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// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm -O0 %s -o - 2>&1 | FileCheck %s
typedef unsigned long size_t;
struct Foo {
int t[10];
};
#define PS(N) __attribute__((pass_object_size(N)))
int gi = 0;
// CHECK-LABEL: define i32 @ObjectSize0(i8* %{{.*}}, i64)
int ObjectSize0(void *const p PS(0)) {
// CHECK-NOT: @llvm.objectsize
return __builtin_object_size(p, 0);
}
// CHECK-LABEL: define i32 @ObjectSize1(i8* %{{.*}}, i64)
int ObjectSize1(void *const p PS(1)) {
// CHECK-NOT: @llvm.objectsize
return __builtin_object_size(p, 1);
}
// CHECK-LABEL: define i32 @ObjectSize2(i8* %{{.*}}, i64)
int ObjectSize2(void *const p PS(2)) {
// CHECK-NOT: @llvm.objectsize
return __builtin_object_size(p, 2);
}
// CHECK-LABEL: define i32 @ObjectSize3(i8* %{{.*}}, i64)
int ObjectSize3(void *const p PS(3)) {
// CHECK-NOT: @llvm.objectsize
return __builtin_object_size(p, 3);
}
// CHECK-LABEL: define void @test1
void test1() {
struct Foo t[10];
// CHECK: call i32 @ObjectSize0(i8* %{{.*}}, i64 360)
gi = ObjectSize0(&t[1]);
// CHECK: call i32 @ObjectSize1(i8* %{{.*}}, i64 360)
gi = ObjectSize1(&t[1]);
// CHECK: call i32 @ObjectSize2(i8* %{{.*}}, i64 360)
gi = ObjectSize2(&t[1]);
// CHECK: call i32 @ObjectSize3(i8* %{{.*}}, i64 360)
gi = ObjectSize3(&t[1]);
// CHECK: call i32 @ObjectSize0(i8* %{{.*}}, i64 356)
gi = ObjectSize0(&t[1].t[1]);
// CHECK: call i32 @ObjectSize1(i8* %{{.*}}, i64 36)
gi = ObjectSize1(&t[1].t[1]);
// CHECK: call i32 @ObjectSize2(i8* %{{.*}}, i64 356)
gi = ObjectSize2(&t[1].t[1]);
// CHECK: call i32 @ObjectSize3(i8* %{{.*}}, i64 36)
gi = ObjectSize3(&t[1].t[1]);
}
// CHECK-LABEL: define void @test2
void test2(struct Foo *t) {
// CHECK: [[VAR:%[0-9]+]] = call i64 @llvm.objectsize
// CHECK: call i32 @ObjectSize1(i8* %{{.*}}, i64 [[VAR]])
gi = ObjectSize1(&t->t[1]);
// CHECK: call i32 @ObjectSize3(i8* %{{.*}}, i64 36)
gi = ObjectSize3(&t->t[1]);
}
// CHECK-LABEL: define i32 @_Z27NoViableOverloadObjectSize0Pv
int NoViableOverloadObjectSize0(void *const p) __attribute__((overloadable)) {
// CHECK: @llvm.objectsize
return __builtin_object_size(p, 0);
}
// CHECK-LABEL: define i32 @_Z27NoViableOverloadObjectSize1Pv
int NoViableOverloadObjectSize1(void *const p) __attribute__((overloadable)) {
// CHECK: @llvm.objectsize
return __builtin_object_size(p, 1);
}
// CHECK-LABEL: define i32 @_Z27NoViableOverloadObjectSize2Pv
int NoViableOverloadObjectSize2(void *const p) __attribute__((overloadable)) {
// CHECK: @llvm.objectsize
return __builtin_object_size(p, 2);
}
// CHECK-LABEL: define i32 @_Z27NoViableOverloadObjectSize3Pv
int NoViableOverloadObjectSize3(void *const p) __attribute__((overloadable)) {
// CHECK-NOT: @llvm.objectsize
return __builtin_object_size(p, 3);
}
// CHECK-LABEL: define i32 @_Z27NoViableOverloadObjectSize0Pv
// CHECK-NOT: @llvm.objectsize
int NoViableOverloadObjectSize0(void *const p PS(0))
__attribute__((overloadable)) {
return __builtin_object_size(p, 0);
}
int NoViableOverloadObjectSize1(void *const p PS(1))
__attribute__((overloadable)) {
return __builtin_object_size(p, 1);
}
int NoViableOverloadObjectSize2(void *const p PS(2))
__attribute__((overloadable)) {
return __builtin_object_size(p, 2);
}
int NoViableOverloadObjectSize3(void *const p PS(3))
__attribute__((overloadable)) {
return __builtin_object_size(p, 3);
}
const static int SHOULDNT_BE_CALLED = -100;
int NoViableOverloadObjectSize0(void *const p PS(0))
__attribute__((overloadable, enable_if(p == 0, "never selected"))) {
return SHOULDNT_BE_CALLED;
}
int NoViableOverloadObjectSize1(void *const p PS(1))
__attribute__((overloadable, enable_if(p == 0, "never selected"))) {
return SHOULDNT_BE_CALLED;
}
int NoViableOverloadObjectSize2(void *const p PS(2))
__attribute__((overloadable, enable_if(p == 0, "never selected"))) {
return SHOULDNT_BE_CALLED;
}
int NoViableOverloadObjectSize3(void *const p PS(3))
__attribute__((overloadable, enable_if(p == 0, "never selected"))) {
return SHOULDNT_BE_CALLED;
}
// CHECK-LABEL: define void @test3
void test3() {
struct Foo t[10];
// CHECK: call i32 @_Z27NoViableOverloadObjectSize0PvU17pass_object_size0(i8* %{{.*}}, i64 360)
gi = NoViableOverloadObjectSize0(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize1PvU17pass_object_size1(i8* %{{.*}}, i64 360)
gi = NoViableOverloadObjectSize1(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize2PvU17pass_object_size2(i8* %{{.*}}, i64 360)
gi = NoViableOverloadObjectSize2(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize3PvU17pass_object_size3(i8* %{{.*}}, i64 360)
gi = NoViableOverloadObjectSize3(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize0PvU17pass_object_size0(i8* %{{.*}}, i64 356)
gi = NoViableOverloadObjectSize0(&t[1].t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize1PvU17pass_object_size1(i8* %{{.*}}, i64 36)
gi = NoViableOverloadObjectSize1(&t[1].t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize2PvU17pass_object_size2(i8* %{{.*}}, i64 356)
gi = NoViableOverloadObjectSize2(&t[1].t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize3PvU17pass_object_size3(i8* %{{.*}}, i64 36)
gi = NoViableOverloadObjectSize3(&t[1].t[1]);
}
// CHECK-LABEL: define void @test4
void test4(struct Foo *t) {
// CHECK: call i32 @_Z27NoViableOverloadObjectSize0PvU17pass_object_size0(i8* %{{.*}}, i64 %{{.*}})
gi = NoViableOverloadObjectSize0(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize1PvU17pass_object_size1(i8* %{{.*}}, i64 %{{.*}})
gi = NoViableOverloadObjectSize1(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize2PvU17pass_object_size2(i8* %{{.*}}, i64 %{{.*}})
gi = NoViableOverloadObjectSize2(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize3PvU17pass_object_size3(i8* %{{.*}}, i64 0)
gi = NoViableOverloadObjectSize3(&t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize0PvU17pass_object_size0(i8* %{{.*}}, i64 %{{.*}})
gi = NoViableOverloadObjectSize0(&t[1].t[1]);
// CHECK: [[VAR:%[0-9]+]] = call i64 @llvm.objectsize
// CHECK: call i32 @_Z27NoViableOverloadObjectSize1PvU17pass_object_size1(i8* %{{.*}}, i64 [[VAR]])
gi = NoViableOverloadObjectSize1(&t[1].t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize2PvU17pass_object_size2(i8* %{{.*}}, i64 %{{.*}})
gi = NoViableOverloadObjectSize2(&t[1].t[1]);
// CHECK: call i32 @_Z27NoViableOverloadObjectSize3PvU17pass_object_size3(i8* %{{.*}}, i64 36)
gi = NoViableOverloadObjectSize3(&t[1].t[1]);
}
void test5() {
struct Foo t[10];
int (*f)(void *) = &NoViableOverloadObjectSize0;
gi = f(&t[1]);
}
// CHECK-LABEL: define i32 @IndirectObjectSize0
int IndirectObjectSize0(void *const p PS(0)) {
// CHECK: call i32 @ObjectSize0(i8* %{{.*}}, i64 %{{.*}})
// CHECK-NOT: @llvm.objectsize
return ObjectSize0(p);
}
// CHECK-LABEL: define i32 @IndirectObjectSize1
int IndirectObjectSize1(void *const p PS(1)) {
// CHECK: call i32 @ObjectSize1(i8* %{{.*}}, i64 %{{.*}})
// CHECK-NOT: @llvm.objectsize
return ObjectSize1(p);
}
// CHECK-LABEL: define i32 @IndirectObjectSize2
int IndirectObjectSize2(void *const p PS(2)) {
// CHECK: call i32 @ObjectSize2(i8* %{{.*}}, i64 %{{.*}})
// CHECK-NOT: @llvm.objectsize
return ObjectSize2(p);
}
// CHECK-LABEL: define i32 @IndirectObjectSize3
int IndirectObjectSize3(void *const p PS(3)) {
// CHECK: call i32 @ObjectSize3(i8* %{{.*}}, i64 %{{.*}})
// CHECK-NOT: @llvm.objectsize
return ObjectSize3(p);
}
int Overload0(void *, size_t, void *, size_t);
int OverloadNoSize(void *, void *);
int OverloadedObjectSize(void *const p PS(0),
void *const c PS(0))
__attribute__((overloadable)) __asm__("Overload0");
int OverloadedObjectSize(void *const p, void *const c)
__attribute__((overloadable)) __asm__("OverloadNoSize");
// CHECK-LABEL: define void @test6
void test6() {
int known[10], *opaque;
// CHECK: call i32 @"\01Overload0"
gi = OverloadedObjectSize(&known[0], &known[0]);
// CHECK: call i32 @"\01Overload0"
gi = OverloadedObjectSize(&known[0], opaque);
// CHECK: call i32 @"\01Overload0"
gi = OverloadedObjectSize(opaque, &known[0]);
// CHECK: call i32 @"\01Overload0"
gi = OverloadedObjectSize(opaque, opaque);
}
int Identity(void *p, size_t i) { return i; }
// CHECK-NOT: define void @AsmObjectSize
int AsmObjectSize0(void *const p PS(0)) __asm__("Identity");
int AsmObjectSize1(void *const p PS(1)) __asm__("Identity");
int AsmObjectSize2(void *const p PS(2)) __asm__("Identity");
int AsmObjectSize3(void *const p PS(3)) __asm__("Identity");
// CHECK-LABEL: define void @test7
void test7() {
struct Foo t[10];
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 360)
gi = AsmObjectSize0(&t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 360)
gi = AsmObjectSize1(&t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 360)
gi = AsmObjectSize2(&t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 360)
gi = AsmObjectSize3(&t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 356)
gi = AsmObjectSize0(&t[1].t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 36)
gi = AsmObjectSize1(&t[1].t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 356)
gi = AsmObjectSize2(&t[1].t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 36)
gi = AsmObjectSize3(&t[1].t[1]);
}
// CHECK-LABEL: define void @test8
void test8(struct Foo *t) {
// CHECK: [[VAR:%[0-9]+]] = call i64 @llvm.objectsize
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 [[VAR]])
gi = AsmObjectSize1(&t[1].t[1]);
// CHECK: call i32 @"\01Identity"(i8* %{{.*}}, i64 36)
gi = AsmObjectSize3(&t[1].t[1]);
}
void DifferingObjectSize0(void *const p __attribute__((pass_object_size(0))));
void DifferingObjectSize1(void *const p __attribute__((pass_object_size(1))));
void DifferingObjectSize2(void *const p __attribute__((pass_object_size(2))));
void DifferingObjectSize3(void *const p __attribute__((pass_object_size(3))));
// CHECK-LABEL: define void @test9
void test9(void *const p __attribute__((pass_object_size(0)))) {
// CHECK: @llvm.objectsize
DifferingObjectSize2(p);
// CHECK-NOT: @llvm.objectsize
DifferingObjectSize0(p);
DifferingObjectSize1(p);
// CHECK: call void @DifferingObjectSize3(i8* %{{.*}}, i64 0)
DifferingObjectSize3(p);
}
// CHECK-LABEL: define void @test10
void test10(void *const p __attribute__((pass_object_size(1)))) {
// CHECK: @llvm.objectsize
DifferingObjectSize2(p);
// CHECK: @llvm.objectsize
DifferingObjectSize0(p);
// CHECK-NOT: @llvm.objectsize
DifferingObjectSize1(p);
// CHECK: call void @DifferingObjectSize3(i8* %{{.*}}, i64 0)
DifferingObjectSize3(p);
}
// CHECK-LABEL: define void @test11
void test11(void *const p __attribute__((pass_object_size(2)))) {
// CHECK: @llvm.objectsize
DifferingObjectSize0(p);
// CHECK: @llvm.objectsize
DifferingObjectSize1(p);
// CHECK-NOT: @llvm.objectsize
DifferingObjectSize2(p);
// CHECK: call void @DifferingObjectSize3(i8* %{{.*}}, i64 0)
DifferingObjectSize3(p);
}
// CHECK-LABEL: define void @test12
void test12(void *const p __attribute__((pass_object_size(3)))) {
// CHECK: @llvm.objectsize
DifferingObjectSize0(p);
// CHECK: @llvm.objectsize
DifferingObjectSize1(p);
// CHECK-NOT: @llvm.objectsize
DifferingObjectSize2(p);
DifferingObjectSize3(p);
}
// CHECK-LABEL: define void @test13
void test13() {
// Ensuring that we don't lower objectsize if the expression has side-effects
char c[10];
char *p = c;
// CHECK: @llvm.objectsize
ObjectSize0(p);
// CHECK-NOT: @llvm.objectsize
ObjectSize0(++p);
ObjectSize0(p++);
}
// There was a bug where variadic functions with pass_object_size would cause
// problems in the form of failed assertions.
void my_sprintf(char *const c __attribute__((pass_object_size(0))), ...) {}
// CHECK-LABEL: define void @test14
void test14(char *c) {
// CHECK: @llvm.objectsize
// CHECK: call void (i8*, i64, ...) @my_sprintf
my_sprintf(c);
// CHECK: @llvm.objectsize
// CHECK: call void (i8*, i64, ...) @my_sprintf
my_sprintf(c, 1, 2, 3);
}
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