llvm-project/clang/test/CodeGen/alloc-token-nonlibcalls.c
Marco Elver dfa8732d05
[AllocToken, Clang] Infer type hints from sizeof expressions and casts (#156841)
For the AllocToken pass to accurately calculate token ID hints, we
need to attach `!alloc_token` metadata for allocation calls.

Unlike new expressions, untyped allocation calls (like `malloc`,
`calloc`, `::operator new(..)`, `__builtin_operator_new`, etc.) have no
syntactic type associated with them. For -fsanitize=alloc-token, type
hints are sufficient, and we can attempt to infer the type based on
common idioms.

When encountering allocation calls (with `__attribute__((malloc))` or
`__attribute__((alloc_size(..))`), attach `!alloc_token` by inferring
the allocated type from (a) sizeof argument expressions such as
`malloc(sizeof(MyType))`, and (b) casts such as `(MyType*)malloc(4096)`.

Note that non-standard allocation functions with these attributes are
not instrumented by default. Use `-fsanitize-alloc-token-extended` to
instrument them as well.

Link: https://discourse.llvm.org/t/rfc-a-framework-for-allocator-partitioning-hints/87434

---

This change is part of the following series:
  1. https://github.com/llvm/llvm-project/pull/160131
  2. https://github.com/llvm/llvm-project/pull/156838
  3. https://github.com/llvm/llvm-project/pull/162098
  4. https://github.com/llvm/llvm-project/pull/162099
  5. https://github.com/llvm/llvm-project/pull/156839
  6. https://github.com/llvm/llvm-project/pull/156840
  7. https://github.com/llvm/llvm-project/pull/156841
  8. https://github.com/llvm/llvm-project/pull/156842
2025-10-09 09:31:16 +02:00

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// RUN: %clang_cc1 -fsanitize=alloc-token -fsanitize-alloc-token-extended -triple x86_64-linux-gnu -emit-llvm -disable-llvm-passes %s -o - | FileCheck --check-prefixes=CHECK,CHECK-CODEGEN %s
// RUN: %clang_cc1 -fsanitize=alloc-token -fsanitize-alloc-token-extended -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,CHECK-LOWER %s
// RUN: %clang_cc1 -O -fsanitize=alloc-token -fsanitize-alloc-token-extended -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck --check-prefixes=CHECK,CHECK-LOWER %s
typedef __typeof(sizeof(int)) size_t;
typedef size_t gfp_t;
void *custom_malloc(size_t size) __attribute__((malloc));
void *__kmalloc(size_t size, gfp_t flags) __attribute__((alloc_size(1)));
void *sink;
// CHECK-LABEL: @test_nonlibcall_alloc(
// CHECK-CODEGEN: call noalias ptr @custom_malloc(i64 noundef 4){{.*}} !alloc_token [[META_INT:![0-9]+]]
// CHECK-CODEGEN: call ptr @__kmalloc(i64 noundef 4, i64 noundef 0){{.*}} !alloc_token [[META_INT]]
// CHECK-LOWER: call{{.*}} noalias ptr @__alloc_token_custom_malloc(i64 noundef 4, i64 2689373973731826898){{.*}} !alloc_token [[META_INT:![0-9]+]]
// CHECK-LOWER: call{{.*}} ptr @__alloc_token___kmalloc(i64 noundef 4, i64 noundef 0, i64 2689373973731826898){{.*}} !alloc_token [[META_INT]]
void test_nonlibcall_alloc() {
sink = custom_malloc(sizeof(int));
sink = __kmalloc(sizeof(int), 0);
}
// CHECK: [[META_INT]] = !{!"int", i1 false}