[libunwind] 5831adb - Revert "[libunwind] Support for leaf function unwinding."

Daniel Kiss via cfe-commits cfe-commits at lists.llvm.org
Fri Sep 18 02:38:18 PDT 2020


Author: Daniel Kiss
Date: 2020-09-18T11:37:54+02:00
New Revision: 5831adb8c38f3fd1b17ff52984c514fc32e893f6

URL: https://github.com/llvm/llvm-project/commit/5831adb8c38f3fd1b17ff52984c514fc32e893f6
DIFF: https://github.com/llvm/llvm-project/commit/5831adb8c38f3fd1b17ff52984c514fc32e893f6.diff

LOG: Revert "[libunwind] Support for leaf function unwinding."

This reverts commit 23bef7ee9923b1262326981960397e8cd95d6923.

Added: 
    

Modified: 
    libunwind/src/DwarfInstructions.hpp
    libunwind/src/DwarfParser.hpp
    libunwind/test/lit.site.cfg.in

Removed: 
    libunwind/test/signal_unwind.pass.cpp
    libunwind/test/unwind_leaffunction.pass.cpp


################################################################################
diff  --git a/libunwind/src/DwarfInstructions.hpp b/libunwind/src/DwarfInstructions.hpp
index c39cabe1f783..ee98f538d437 100644
--- a/libunwind/src/DwarfInstructions.hpp
+++ b/libunwind/src/DwarfInstructions.hpp
@@ -93,8 +93,7 @@ typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
 
   case CFI_Parser<A>::kRegisterInRegister:
     return registers.getRegister((int)savedReg.value);
-  case CFI_Parser<A>::kRegisterUndefined:
-    return 0;
+
   case CFI_Parser<A>::kRegisterUnused:
   case CFI_Parser<A>::kRegisterOffsetFromCFA:
     // FIX ME
@@ -118,7 +117,6 @@ double DwarfInstructions<A, R>::getSavedFloatRegister(
 
   case CFI_Parser<A>::kRegisterIsExpression:
   case CFI_Parser<A>::kRegisterUnused:
-  case CFI_Parser<A>::kRegisterUndefined:
   case CFI_Parser<A>::kRegisterOffsetFromCFA:
   case CFI_Parser<A>::kRegisterInRegister:
     // FIX ME
@@ -142,7 +140,6 @@ v128 DwarfInstructions<A, R>::getSavedVectorRegister(
 
   case CFI_Parser<A>::kRegisterIsExpression:
   case CFI_Parser<A>::kRegisterUnused:
-  case CFI_Parser<A>::kRegisterUndefined:
   case CFI_Parser<A>::kRegisterOffsetFromCFA:
   case CFI_Parser<A>::kRegisterInRegister:
     // FIX ME
@@ -193,10 +190,6 @@ int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
                                     prolog.savedRegisters[i]));
           else
             return UNW_EBADREG;
-        } else if (i == (int)cieInfo.returnAddressRegister) {
-            // Leaf function keeps the return address in register and there is no
-            // explicit intructions how to restore it.
-            returnAddress = registers.getRegister(cieInfo.returnAddressRegister);
         }
       }
 

diff  --git a/libunwind/src/DwarfParser.hpp b/libunwind/src/DwarfParser.hpp
index 86c0522afd3f..fb943edfdb7e 100644
--- a/libunwind/src/DwarfParser.hpp
+++ b/libunwind/src/DwarfParser.hpp
@@ -69,7 +69,6 @@ class CFI_Parser {
   };
   enum RegisterSavedWhere {
     kRegisterUnused,
-    kRegisterUndefined,
     kRegisterInCFA,
     kRegisterOffsetFromCFA,
     kRegisterInRegister,
@@ -506,7 +505,7 @@ bool CFI_Parser<A>::parseInstructions(A &addressSpace, pint_t instructions,
                 "malformed DW_CFA_undefined DWARF unwind, reg too big");
         return false;
       }
-      results->setRegisterLocation(reg, kRegisterUndefined, initialState);
+      results->setRegisterLocation(reg, kRegisterUnused, initialState);
       _LIBUNWIND_TRACE_DWARF("DW_CFA_undefined(reg=%" PRIu64 ")\n", reg);
       break;
     case DW_CFA_same_value:

diff  --git a/libunwind/test/lit.site.cfg.in b/libunwind/test/lit.site.cfg.in
index 84dae3c2bfb0..8ff770fe29bc 100644
--- a/libunwind/test/lit.site.cfg.in
+++ b/libunwind/test/lit.site.cfg.in
@@ -44,10 +44,6 @@ config.test_source_root = os.path.join(config.libunwind_src_root, 'test')
 # Allow expanding substitutions that are based on other substitutions
 config.recursiveExpansionLimit = 10
 
-# Make symbols available in the tests.
-config.test_compiler_flags += " -funwind-tables "
-config.test_linker_flags += " -Wl,--export-dynamic "
-
 # Infer the test_exec_root from the build directory.
 config.test_exec_root = os.path.join(config.libunwind_obj_root, 'test')
 

diff  --git a/libunwind/test/signal_unwind.pass.cpp b/libunwind/test/signal_unwind.pass.cpp
deleted file mode 100644
index 295dd75bb726..000000000000
--- a/libunwind/test/signal_unwind.pass.cpp
+++ /dev/null
@@ -1,44 +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
-//
-//===----------------------------------------------------------------------===//
-
-// Ensure that the unwinder can cope with the signal handler.
-
-#include <assert.h>
-#include <dlfcn.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <unwind.h>
-
-_Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
-  (void)arg;
-  Dl_info info = { 0, 0, 0, 0 };
-  assert(dladdr((void*)_Unwind_GetIP(ctx), &info));
-
-  // Unwind util the main is reached, above frames deeped on the platfrom and architecture.
-  if(info.dli_sname && !strcmp("main", info.dli_sname)) {
-    _Exit(0);
-  }
-  return _URC_NO_REASON;
-}
-
-void signal_handler(int signum) {
-  (void)signum;
-  _Unwind_Backtrace(frame_handler, NULL);
-  _Exit(-1);
-}
-
-int main() {
-  signal(SIGUSR1, signal_handler);
-  kill(getpid(), SIGUSR1);
-  return -2;
-}

diff  --git a/libunwind/test/unwind_leaffunction.pass.cpp b/libunwind/test/unwind_leaffunction.pass.cpp
deleted file mode 100644
index b8a114516d0a..000000000000
--- a/libunwind/test/unwind_leaffunction.pass.cpp
+++ /dev/null
@@ -1,50 +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
-//
-//===----------------------------------------------------------------------===//
-
-// Ensure that leaf function can be unwund.
-
-#include <assert.h>
-#include <dlfcn.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <unwind.h>
-
-_Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
-  (void)arg;
-  Dl_info info = { 0, 0, 0, 0 };
-  assert(dladdr((void*)_Unwind_GetIP(ctx), &info));
-
-  // Unwind util the main is reached, above frames deeped on the platfrom and architecture.
-  if(info.dli_sname && !strcmp("main", info.dli_sname)) {
-    _Exit(0);
-  }
-  return _URC_NO_REASON;
-}
-
-void signal_handler(int signum) {
-  (void)signum;
-  _Unwind_Backtrace(frame_handler, NULL);
-  _Exit(-1);
-}
-
-int* faultyPointer = NULL;
-
-__attribute__((noinline)) void crashing_leaf_func(void) {
-  *faultyPointer = 0;
-}
-
-int main() {
-  signal(SIGSEGV, signal_handler);
-  crashing_leaf_func();
-  return -2;
-}
\ No newline at end of file


        


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