From fd864238fca1435cb1ceffdca0d4294cf3419ac7 Mon Sep 17 00:00:00 2001
From: Daniel Kiss <daniel.kiss@arm.com>
Date: Sun, 15 May 2022 21:42:07 +0200
Subject: [PATCH] Revert "[libunwind][AArch64] Add support for DWARF expression
 for RA_SIGN_STATE."

This reverts commit f6366ef7f4f3cf1182fd70e0c50a9fa54374b612.
---
 libunwind/src/DwarfInstructions.hpp           | 21 +--------
 libunwind/test/aarch64.ra_sign_state.pass.cpp | 63 ---------------------------
 2 files changed, 1 insertion(+), 83 deletions(-)
 delete mode 100644 libunwind/test/aarch64.ra_sign_state.pass.cpp

diff --git a/libunwind/src/DwarfInstructions.hpp b/libunwind/src/DwarfInstructions.hpp
index a4fac5a..ab83b0c 100644
--- a/libunwind/src/DwarfInstructions.hpp
+++ b/libunwind/src/DwarfInstructions.hpp
@@ -72,10 +72,6 @@ private:
     assert(0 && "getCFA(): unknown location");
     __builtin_unreachable();
   }
-#if defined(_LIBUNWIND_TARGET_AARCH64)
-  static bool getRA_SIGN_STATE(A &addressSpace, R registers, pint_t cfa,
-                               PrologInfo &prolog);
-#endif
 };
 
 template <typename R>
@@ -170,21 +166,6 @@ v128 DwarfInstructions<A, R>::getSavedVectorRegister(
   }
   _LIBUNWIND_ABORT("unsupported restore location for vector register");
 }
-#if defined(_LIBUNWIND_TARGET_AARCH64)
-template <typename A, typename R>
-bool DwarfInstructions<A, R>::getRA_SIGN_STATE(A &addressSpace, R registers,
-                                               pint_t cfa, PrologInfo &prolog) {
-  pint_t raSignState;
-  auto regloc = prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE];
-  if (regloc.location == CFI_Parser<A>::kRegisterUnused)
-    raSignState = static_cast<pint_t>(regloc.value);
-  else
-    raSignState = getSavedRegister(addressSpace, registers, cfa, regloc);
-
-  // Only bit[0] is meaningful.
-  return raSignState & 0x01;
-}
-#endif
 
 template <typename A, typename R>
 int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
@@ -254,7 +235,7 @@ int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
       // restored. autia1716 is used instead of autia as autia1716 assembles
       // to a NOP on pre-v8.3a architectures.
       if ((R::getArch() == REGISTERS_ARM64) &&
-          getRA_SIGN_STATE(addressSpace, registers, cfa, prolog) &&
+          prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE].value &&
           returnAddress != 0) {
 #if !defined(_LIBUNWIND_IS_NATIVE_ONLY)
         return UNW_ECROSSRASIGNING;
diff --git a/libunwind/test/aarch64.ra_sign_state.pass.cpp b/libunwind/test/aarch64.ra_sign_state.pass.cpp
deleted file mode 100644
index 1e09c93..0000000
--- a/libunwind/test/aarch64.ra_sign_state.pass.cpp
+++ /dev/null
@@ -1,63 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-// REQUIRES: linux && target={{aarch64-.+}}
-
-// This test ensures the .cfi_negate_ra_state the RA_SIGN_STATE pseudo register
-// could be set directly set by a DWARF expression and the unwinder handles it
-// correctly. The two directives can't be mixed in one CIE/FDE sqeuence.
-
-#include <stdlib.h>
-
-__attribute__((noinline, target("branch-protection=pac-ret+leaf")))
-void bar() {
-  // ".cfi_negate_ra_state" is emitted by the compiler.
-  throw 1;
-}
-
-__attribute__((noinline, target("branch-protection=none")))
-void foo() {
-  // Here a DWARF expression sets RA_SIGN_STATE.
-  // The LR is signed manually and stored on the stack.
-  asm volatile(
-      ".cfi_escape 0x16,"    // DW_CFA_val_expression
-                    "34,"    // REG_34(RA_SIGN_STATE)
-                     "1,"    // expression_length(1)
-                    "0x31\n" // DW_OP_lit1
-      "add sp, sp, 16\n"     // Restore SP's value before the stack frame is
-                             // created.
-      "paciasp\n"            // Sign the LR.
-      "str lr, [sp, -0x8]\n" // Overwrite LR on the stack.
-      "sub sp, sp, 16\n"     // Restore SP's value.
-  );
-  bar();
-  _Exit(-1);
-}
-
-__attribute__((noinline, target("branch-protection=pac-ret")))
-void bazz() {
-  // ".cfi_negate_ra_state" is emitted by the compiler.
-  try {
-    foo();
-  } catch (int i) {
-    if (i == 1)
-      throw i;
-    throw 2;
-  }
-}
-
-int main() {
-  try {
-    bazz();
-  } catch (int i) {
-    if (i == 1)
-      _Exit(0);
-  }
-  return -1;
-}
-- 
2.7.4