git: 5866c369e4fd - main - Revert libunwind change to fix backtrace segfault on aarch64
Dimitry Andric
dim at FreeBSD.org
Fri Jul 2 22:36:20 UTC 2021
The branch main has been updated by dim:
URL: https://cgit.FreeBSD.org/src/commit/?id=5866c369e4fd917c0d456f0f10b92ee354b82279
commit 5866c369e4fd917c0d456f0f10b92ee354b82279
Author: Dimitry Andric <dim at FreeBSD.org>
AuthorDate: 2021-07-02 22:35:42 +0000
Commit: Dimitry Andric <dim at FreeBSD.org>
CommitDate: 2021-07-02 22:35:49 +0000
Revert libunwind change to fix backtrace segfault on aarch64
Revert commit 22b615a96593 from llvm git (by Daniel Kiss):
[libunwind] Support for leaf function unwinding.
Unwinding leaf function is useful in cases when the backtrace finds a
leaf function for example when it caused a signal.
This patch also add the support for the DW_CFA_undefined because it marks
the end of the frames.
Ryan Prichard provided code for the tests.
Reviewed By: #libunwind, mstorsjo
Differential Revision: https://reviews.llvm.org/D83573
Reland with limit the test to the x86_64-linux target.
Bisection has shown that this particular upstream commit causes programs
using backtrace(3) on aarch64 to segfault. This affects the lang/rust
port, for instance. Until we can upstream to fix this problem, revert
the commit for now.
Reported by: mikael
PR: 256864
---
contrib/llvm-project/libunwind/src/DwarfInstructions.hpp | 9 +--------
contrib/llvm-project/libunwind/src/DwarfParser.hpp | 3 +--
2 files changed, 2 insertions(+), 10 deletions(-)
diff --git a/contrib/llvm-project/libunwind/src/DwarfInstructions.hpp b/contrib/llvm-project/libunwind/src/DwarfInstructions.hpp
index c39cabe1f783..ee98f538d437 100644
--- a/contrib/llvm-project/libunwind/src/DwarfInstructions.hpp
+++ b/contrib/llvm-project/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/contrib/llvm-project/libunwind/src/DwarfParser.hpp b/contrib/llvm-project/libunwind/src/DwarfParser.hpp
index de0eb6de9d70..b41cc7bcfda2 100644
--- a/contrib/llvm-project/libunwind/src/DwarfParser.hpp
+++ b/contrib/llvm-project/libunwind/src/DwarfParser.hpp
@@ -69,7 +69,6 @@ public:
};
enum RegisterSavedWhere {
kRegisterUnused,
- kRegisterUndefined,
kRegisterInCFA,
kRegisterOffsetFromCFA,
kRegisterInRegister,
@@ -503,7 +502,7 @@ bool CFI_Parser<A>::parseFDEInstructions(A &addressSpace,
"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:
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