[compiler-rt] [libcxx] [libcxxabi] [libunwind] [runtimes][PAC] Harden unwinding when possible (PR #143230)

[Daniil Kovalev via llvm-commits]

================
@@ -43,6 +43,104 @@
   #define LIBUNWIND_AVAIL
 #endif
 
+#if __has_feature(ptrauth_calls)
+
+  #include <ptrauth.h>
+
+  #if __has_extension(ptrauth_restricted_intptr_qualifier)
+    #define __unwind_ptrauth_restricted_intptr(...) \
+      __ptrauth_restricted_intptr(__VA_ARGS__)
+  #else
+    #define __unwind_ptrauth_restricted_intptr(...) \
+      __ptrauth(__VA_ARGS__)
+  #endif
+
+// ptrauth_string_discriminator("unw_proc_info_t::handler") == 0x7405
+  #define __ptrauth_unwind_upi_handler_disc 0x7405
+
+  #define __ptrauth_unwind_upi_handler \
+    __ptrauth(ptrauth_key_function_pointer, 1, __ptrauth_unwind_upi_handler_disc)
+
+  #define __ptrauth_unwind_upi_handler_intptr \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_function_pointer, 1,\
+                                       __ptrauth_unwind_upi_handler_disc)
+
+// ptrauth_string_discriminator("unw_proc_info_t::start_ip") == 0xCA2C
+  #define __ptrauth_unwind_upi_startip \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_independent_code, 1, 0xCA2C)
+
+// ptrauth_string_discriminator("unw_proc_info_t::end_ip") == 0xE183
+  #define __ptrauth_unwind_upi_endip \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_independent_code, 1, 0xE183)
+
+// ptrauth_string_discriminator("unw_proc_info_t::lsda") == 0x83DE
+  #define __ptrauth_unwind_upi_lsda \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x83DE)
+
+// ptrauth_string_discriminator("unw_proc_info_t::flags") == 0x79A1
+  #define __ptrauth_unwind_upi_flags \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x79A1)
+
+// ptrauth_string_discriminator("unw_proc_info_t::unwind_info") == 0xC20C
+  #define __ptrauth_unwind_upi_info \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0xC20C)
+
+// ptrauth_string_discriminator("unw_proc_info_t::extra") == 0x03DF
+  #define __ptrauth_unwind_upi_extra \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x03DF)
+
+// ptrauth_string_discriminator("Registers_arm64::link_reg_t") == 0x8301
+  #define __ptrauth_unwind_registers_arm64_link_reg \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_code, 1, 0x8301)
+
+// ptrauth_string_discriminator("UnwindInfoSections::dso_base") == 0x4FF5
+  #define __ptrauth_unwind_uis_dso_base \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x4FF5)
+
+// ptrauth_string_discriminator("UnwindInfoSections::dwarf_section") == 0x4974
+  #define __ptrauth_unwind_uis_dwarf_section \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x4974)
+
+// ptrauth_string_discriminator("UnwindInfoSections::dwarf_section_length") == 0x2A9A
+  #define __ptrauth_unwind_uis_dwarf_section_length \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x2A9A)
+
+// ptrauth_string_discriminator("UnwindInfoSections::compact_unwind_section") == 0xA27B
+  #define __ptrauth_unwind_uis_compact_unwind_section \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0xA27B)
+
+// ptrauth_string_discriminator("UnwindInfoSections::compact_unwind_section_length") == 0x5D0A
+  #define __ptrauth_unwind_uis_compact_unwind_section_length \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_process_dependent_data, 1, 0x5D0A)
+
+// ptrauth_string_discriminator("CIE_Info::personality") == 0x6A40
+  #define __ptrauth_unwind_cie_info_personality_disc 0x6A40
+  #define __ptrauth_unwind_cie_info_personality \
+    __unwind_ptrauth_restricted_intptr(ptrauth_key_function_pointer, 1, \
+                                       __ptrauth_unwind_cie_info_personality_disc)
+
+// ptrauth_string_discriminator("personality") == 0x7EAD)
+  #define __ptrauth_unwind_pacret_personality_disc 0x7EAD
----------------
kovdan01 wrote:

I suppose the name is a bit misleading. Let's use smth like the following:
```suggestion
  #define __ptrauth_unwind_pauthtest_personality_disc 0x7EAD
```

https://github.com/llvm/llvm-project/pull/143230