[llvm-branch-commits] [clang] [clang] Define ptrauth_sign_constant builtin. (PR #93904)

[Daniil Kovalev via llvm-branch-commits]

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@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-intrinsics -emit-llvm %s  -o - | FileCheck %s
+// RUN: %clang_cc1 -triple aarch64-elf     -fptrauth-intrinsics -emit-llvm %s  -o - | FileCheck %s
+
+extern int external;
+
+// CHECK: @ptr1 = global ptr ptrauth (ptr @external, i32 0, i64 26)
+void *ptr1 = __builtin_ptrauth_sign_constant(&external, 0, 26);
+
+// CHECK: @ptr2 = global ptr ptrauth (ptr @external, i32 2, i64 26, ptr @ptr2)
+void *ptr2 = __builtin_ptrauth_sign_constant(&external, 2, __builtin_ptrauth_blend_discriminator(&ptr2, 26));
+
+// CHECK: @ptr3 = global ptr null
+void *ptr3;
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kovdan01 wrote:

Feel free to ignore: probably worth adding test for smth like

```
void *ptr4 = __builtin_ptrauth_sign_constant(&external, 0, NULL);
```

This doesn't bring that much value over testing a non-null constant integer discriminator, but:
1. In docs, having null pointer as a discriminator is listed as a separate option
   > This is a constant expression if the extra data is an integer or
   null pointer constant. 
2. With `NULL` defined as `#define NULL ((void*) 0)`, we'll explicitly test having a constant pointer, not an integer, value as a discriminator

https://github.com/llvm/llvm-project/pull/93904