am f96eaf62: Merge "[x86,x86_64] Fix libgcc unwinding through signal"

* commit 'f96eaf6202351a1b5153cfaad3137e4b63846f8f':
  [x86,x86_64] Fix libgcc unwinding through signal

libc/arch-x86/bionic/__restore.S

@@ -28,10 +28,108 @@
 
 #include <private/bionic_asm.h>
 
-// This function must have exactly this instruction sequence for gdb and libunwind.
+// DWARF constants.
-// This function must have exactly this name for gdb.
+#define DW_CFA_def_cfa_expression 0x0f
-ENTRY(__restore)
+#define DW_CFA_expression 0x10
+#define DW_EH_PE_pcrel 0x10
+#define DW_EH_PE_sdata4 0x0b
+#define DW_OP_breg4 0x74
+#define DW_OP_deref 0x06
+
+// Offsets into struct sigcontext.
+#define OFFSET_EDI 16
+#define OFFSET_ESI 20
+#define OFFSET_EBP 24
+#define OFFSET_ESP 28
+#define OFFSET_EBX 32
+#define OFFSET_EDX 36
+#define OFFSET_ECX 40
+#define OFFSET_EAX 44
+#define OFFSET_EIP 56
+
+// Non-standard DWARF constants for the x86 registers.
+#define DW_x86_REG_EAX 0
+#define DW_x86_REG_ECX 1
+#define DW_x86_REG_EDX 2
+#define DW_x86_REG_EBX 3
+#define DW_x86_REG_EBP 5
+#define DW_x86_REG_ESI 6
+#define DW_x86_REG_EDI 7
+#define DW_x86_REG_EIP 8
+
+#define cfi_signal_frame_start(f) \
+.section .eh_frame,"a",@progbits; \
+.L ## f ## _START_EH_FRAME: \
+  .long 2f - 1f; /* CIE length. */ \
+1:.long 0;       /* CIE ID. */ \
+  .byte 1;       /* Version. */ \
+  .string "zRS"; /* Augmentation string. */ \
+  .uleb128 1;    /* Code alignment factor. */ \
+  .sleb128 -4;   /* Data alignment factor. */ \
+  .uleb128 DW_x86_REG_EIP;    /* Return address register. */ \
+  .uleb128 1;    /* 1 byte of augmentation data. */ \
+  .byte (DW_EH_PE_pcrel|DW_EH_PE_sdata4); /* FDE encoding. */ \
+  .align 8; \
+2: \
+  .long .L ## f ## _END_FDE - .L ## f ## _START_FDE;   /* FDE length. */ \
+.L ## f ## _START_FDE: \
+  .long .L ## f ## _START_FDE - .L ## f ## _START_EH_FRAME; /* CIE location. */ \
+  .long (.L ## f ## _START - 1) - .;                   /* pcrel start address (see FDE encoding above). */ \
+  .long .L ## f ## _END - (.L ## f ## _START - 1);     /* Function this FDE applies to. */ \
+  .uleb128 0;                                          /* FDE augmentation length. */ \
+
+#define cfi_signal_frame_end(f) \
+.L ## f ## _END_FDE: \
+
+#define cfi_def_cfa(offset) \
+  .byte DW_CFA_def_cfa_expression; \
+  .uleb128 2f-1f; \
+1:.byte DW_OP_breg4; \
+  .sleb128 offset; \
+  .byte DW_OP_deref; \
+2: \
+
+#define cfi_offset(reg_number,offset) \
+  .byte DW_CFA_expression; \
+  .uleb128 reg_number; \
+  .uleb128 2f-1f; \
+1:.byte DW_OP_breg4; \
+  .sleb128 offset; \
+2: \
+
+ENTRY_PRIVATE(__restore)
+.L__restore_START:
   popl %eax
   movl $__NR_sigreturn, %eax
   int $0x80
+.L__restore_END:
 END(__restore)
+cfi_signal_frame_start(__restore)
+  cfi_def_cfa(OFFSET_ESP + 4)
+  cfi_offset(DW_x86_REG_EDI, OFFSET_EDI + 4)
+  cfi_offset(DW_x86_REG_ESI, OFFSET_ESI + 4)
+  cfi_offset(DW_x86_REG_EBP, OFFSET_EBP + 4)
+  cfi_offset(DW_x86_REG_EBX, OFFSET_EBX + 4)
+  cfi_offset(DW_x86_REG_EDX, OFFSET_EDX + 4)
+  cfi_offset(DW_x86_REG_ECX, OFFSET_ECX + 4)
+  cfi_offset(DW_x86_REG_EAX, OFFSET_EAX + 4)
+  cfi_offset(DW_x86_REG_EIP, OFFSET_EIP + 4)
+cfi_signal_frame_end(__restore)
+
+ENTRY_PRIVATE(__restore_rt)
+.L__restore_rt_START:
+  movl $__NR_rt_sigreturn, %eax
+  int $0x80
+.L__restore_rt_END:
+END(__restore_rt)
+cfi_signal_frame_start(__restore_rt)
+  cfi_def_cfa(OFFSET_ESP + 160)
+  cfi_offset(DW_x86_REG_EDI, OFFSET_EDI + 160)
+  cfi_offset(DW_x86_REG_ESI, OFFSET_ESI + 160)
+  cfi_offset(DW_x86_REG_EBP, OFFSET_EBP + 160)
+  cfi_offset(DW_x86_REG_EBX, OFFSET_EBX + 160)
+  cfi_offset(DW_x86_REG_EDX, OFFSET_EDX + 160)
+  cfi_offset(DW_x86_REG_ECX, OFFSET_ECX + 160)
+  cfi_offset(DW_x86_REG_EAX, OFFSET_EAX + 160)
+  cfi_offset(DW_x86_REG_EIP, OFFSET_EIP + 160)
+cfi_signal_frame_end(__restore_rt)

libc/arch-x86/bionic/__restore_rt.S

@@ -1,36 +0,0 @@
-/*
- * Copyright (C) 2014 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <private/bionic_asm.h>
-
-// This function must have exactly this instruction sequence for gdb and libunwind.
-// This function must have exactly this name for gdb.
-ENTRY(__restore_rt)
-  movl $__NR_rt_sigreturn, %eax
-  int $0x80
-END(__restore_rt)

libc/arch-x86/x86.mk

@@ -39,7 +39,6 @@ libc_bionic_src_files_x86 += \
     arch-x86/bionic/__bionic_clone.S \
     arch-x86/bionic/_exit_with_stack_teardown.S \
     arch-x86/bionic/libgcc_compat.c \
-    arch-x86/bionic/__restore_rt.S \
     arch-x86/bionic/__restore.S \
     arch-x86/bionic/_setjmp.S \
     arch-x86/bionic/setjmp.S \

libc/arch-x86_64/bionic/__restore_rt.S

@@ -28,9 +28,116 @@
 
 #include <private/bionic_asm.h>
 
-// This function must have exactly this instruction sequence for gdb and libunwind.
+// DWARF constants.
-// This function must have exactly this name for gdb.
+#define DW_CFA_def_cfa_expression 0x0f
-ENTRY(__restore_rt)
+#define DW_CFA_expression 0x10
+#define DW_EH_PE_pcrel 0x10
+#define DW_EH_PE_sdata4 0x0b
+#define DW_OP_breg4 0x74
+#define DW_OP_breg7 0x77
+#define DW_OP_deref 0x06
+
+// Offsets into struct ucontext_t of uc_mcontext.gregs[x].
+#define OFFSET_R8 40
+#define OFFSET_R9 48
+#define OFFSET_R10 56
+#define OFFSET_R11 64
+#define OFFSET_R12 72
+#define OFFSET_R13 80
+#define OFFSET_R14 88
+#define OFFSET_R15 96
+#define OFFSET_RDI 104
+#define OFFSET_RSI 112
+#define OFFSET_RBP 120
+#define OFFSET_RSP 160
+#define OFFSET_RBX 128
+#define OFFSET_RDX 136
+#define OFFSET_RAX 144
+#define OFFSET_RCX 152
+#define OFFSET_RIP 168
+
+// Non-standard DWARF constants for the x86-64 registers.
+#define DW_x86_64_RAX 0
+#define DW_x86_64_RDX 1
+#define DW_x86_64_RCX 2
+#define DW_x86_64_RBX 3
+#define DW_x86_64_RSI 4
+#define DW_x86_64_RDI 5
+#define DW_x86_64_RBP 6
+#define DW_x86_64_RSP 7
+#define DW_x86_64_R8 8
+#define DW_x86_64_R9 9
+#define DW_x86_64_R10 10
+#define DW_x86_64_R11 11
+#define DW_x86_64_R12 12
+#define DW_x86_64_R13 13
+#define DW_x86_64_R14 14
+#define DW_x86_64_R15 15
+#define DW_x86_64_RIP 16
+
+#define cfi_signal_frame_start(f) \
+.section .eh_frame,"a",@progbits; \
+.L ## f ## _START_EH_FRAME: \
+  .long 2f - 1f; /* CIE length. */ \
+1:.long 0;       /* CIE ID. */ \
+  .byte 1;       /* Version. */ \
+  .string "zRS"; /* Augmentation string. */ \
+  .uleb128 1;    /* Code alignment factor. */ \
+  .sleb128 -8;   /* Data alignment factor. */ \
+  .uleb128 DW_x86_64_RIP;   /* Return address register. */ \
+  .uleb128 1;    /* 1 byte of augmentation data. */ \
+  .byte (DW_EH_PE_pcrel | DW_EH_PE_sdata4); /* FDE encoding. */ \
+  .align 8; \
+2: \
+  .long .L ## f ## _END_FDE - .L ## f ## _START_FDE;   /* FDE length. */ \
+.L ## f ## _START_FDE: \
+  .long .L ## f ## _START_FDE - .L ## f ## _START_EH_FRAME; /* CIE location. */ \
+  .long (.L ## f ## _START - 1) - .;                   /* pcrel start address (see FDE encoding above). */ \
+  .long .L ## f ## _END - (.L ## f ## _START - 1);     /* Function this FDE applies to. */ \
+  .uleb128 0;                                          /* FDE augmentation length. */ \
+
+#define cfi_signal_frame_end(f) \
+.L ## f ## _END_FDE: \
+
+#define cfi_def_cfa(offset) \
+  .byte DW_CFA_def_cfa_expression; \
+  .uleb128 2f-1f; \
+1:.byte DW_OP_breg7; \
+  .sleb128 offset; \
+  .byte DW_OP_deref; \
+2: \
+
+#define cfi_offset(reg_number,offset) \
+  .byte DW_CFA_expression; \
+  .uleb128 reg_number; \
+  .uleb128 2f-1f; \
+1:.byte DW_OP_breg7; \
+  .sleb128 offset; \
+2: \
+
+ENTRY_PRIVATE(__restore_rt)
+.L__restore_rt_START:
   mov $__NR_rt_sigreturn, %rax
   syscall
+.L__restore_rt_END:
 END(__restore_rt)
+cfi_signal_frame_start(__restore_rt)
+  cfi_def_cfa(OFFSET_RSP)
+  cfi_offset(DW_x86_64_R8, OFFSET_R8)
+  cfi_offset(DW_x86_64_R9, OFFSET_R9)
+  cfi_offset(DW_x86_64_R10, OFFSET_R10)
+  cfi_offset(DW_x86_64_R11, OFFSET_R11)
+  cfi_offset(DW_x86_64_R12, OFFSET_R12)
+  cfi_offset(DW_x86_64_R13, OFFSET_R13)
+  cfi_offset(DW_x86_64_R14, OFFSET_R14)
+  cfi_offset(DW_x86_64_R15, OFFSET_R15)
+  cfi_offset(DW_x86_64_RDI, OFFSET_RDI)
+  cfi_offset(DW_x86_64_RSI, OFFSET_RSI)
+  cfi_offset(DW_x86_64_RBP, OFFSET_RBP)
+  cfi_offset(DW_x86_64_RSP, OFFSET_RSP)
+  cfi_offset(DW_x86_64_RBX, OFFSET_RBX)
+  cfi_offset(DW_x86_64_RDX, OFFSET_RDX)
+  cfi_offset(DW_x86_64_RAX, OFFSET_RAX)
+  cfi_offset(DW_x86_64_RCX, OFFSET_RCX)
+  cfi_offset(DW_x86_64_RIP, OFFSET_RIP)
+cfi_signal_frame_end(__restore_rt)

tests/Android.mk

@@ -91,6 +91,7 @@ libBionicStandardTests_src_files := \
     semaphore_test.cpp \
     signal_test.cpp \
     stack_protector_test.cpp \
+    stack_unwinding_test.cpp \
     stdatomic_test.cpp \
     stdint_test.cpp \
     stdio_test.cpp \
@@ -234,8 +235,6 @@ bionic-unit-tests_src_files := \
     atexit_test.cpp \
     dlext_test.cpp \
     dlfcn_test.cpp \
-    stack_unwinding_test.cpp \
-    stack_unwinding_test_impl.c \
 
 bionic-unit-tests_cflags := $(test_cflags)
 

tests/ScopedSignalHandler.h

@@ -21,9 +21,10 @@
 
 class ScopedSignalHandler {
  public:
-  ScopedSignalHandler(int signal_number, void (*handler)(int)) : signal_number_(signal_number) {
+  ScopedSignalHandler(int signal_number, void (*handler)(int), int sa_flags = 0)
+      : signal_number_(signal_number) {
     sigemptyset(&action_.sa_mask);
-    action_.sa_flags = 0;
+    action_.sa_flags = sa_flags;
     action_.sa_handler = handler;
     sigaction(signal_number_, &action_, &old_action_);
   }

tests/stack_unwinding_test.cpp

@@ -31,7 +31,8 @@
 
 #include "ScopedSignalHandler.h"
 
-#define noinline __attribute__((noinline))
+#define noinline __attribute__((__noinline__))
+#define __unused __attribute__((__unused__))
 
 static _Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx __unused, void* arg) {
   int* count_ptr = reinterpret_cast<int*>(arg);
@@ -85,6 +86,7 @@ static void noinline UnwindSignalHandler(int) {
 }
 
 TEST(stack_unwinding, unwind_through_signal_frame) {
+  killer_count = handler_count = handler_one_deeper_count = 0;
   ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler);
 
   _Unwind_Backtrace(FrameCounter, &killer_count);
@@ -92,11 +94,12 @@ TEST(stack_unwinding, unwind_through_signal_frame) {
   ASSERT_EQ(0, kill(getpid(), SIGUSR1));
 }
 
-extern "C" void unwind_through_frame_with_cleanup_function();
+// On LP32, the SA_SIGINFO flag gets you __restore_rt instead of __restore.
+TEST(stack_unwinding, unwind_through_signal_frame_SA_SIGINFO) {
+  killer_count = handler_count = handler_one_deeper_count = 0;
+  ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler, SA_SIGINFO);
 
-// We have to say "DeathTest" here so gtest knows to run this test (which exits)
+  _Unwind_Backtrace(FrameCounter, &killer_count);
-// in its own process.
+
-TEST(stack_unwinding_DeathTest, unwind_through_frame_with_cleanup_function) {
+  ASSERT_EQ(0, kill(getpid(), SIGUSR1));
-  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
-  ASSERT_EXIT(unwind_through_frame_with_cleanup_function(), ::testing::ExitedWithCode(42), "");
 }

tests/stack_unwinding_test_impl.c

@@ -1,64 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/*
- * Contributed by: Intel Corporation
- */
-
-#include <dlfcn.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <unwind.h>
-
-#define noinline __attribute__((__noinline__))
-
-#ifndef __unused
-#define __unused __attribute__((__unused__))
-#endif
-
-static noinline _Unwind_Reason_Code cleanup_unwind_fn(int a __unused,
-    _Unwind_Action action,
-    _Unwind_Exception_Class b __unused,
-    struct _Unwind_Exception* c __unused,
-    struct _Unwind_Context* ctx __unused,
-    void* e __unused) {
-  if ((action & _UA_END_OF_STACK) != 0) {
-    abort(); // We reached the end of the stack without executing foo_cleanup (which would have exited). Test failed.
-  }
-  return _URC_NO_REASON;
-}
-
-static void noinline foo_cleanup(char* param __unused) {
-  exit(42);
-}
-
-static void noinline function_with_cleanup_function() {
-  char c __attribute__((cleanup(foo_cleanup))) __unused;
-  *((int*) 1) = 0;
-}
-
-static void noinline cleanup_sigsegv_handler(int param __unused) {
-  struct _Unwind_Exception* exception = (struct _Unwind_Exception*) calloc(1, sizeof(*exception));
-  _Unwind_ForcedUnwind(exception, cleanup_unwind_fn, 0);
-}
-
-void unwind_through_frame_with_cleanup_function() {
-  signal(SIGSEGV, &cleanup_sigsegv_handler);
-  function_with_cleanup_function();
-}