mirror of
https://github.com/JakeHillion/object-introspection.git
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11588ef837
The current hacked together location API we added to drgn works extremely poorly with modern C++ compilers. It largely works with the clang-12 compiler on CircleCI, but works very poorly with clang 15/16/17/18 in Nix or when updating the CircleCI compiler to clang-15. This change adds a backup mechanism for locating arguments when drgn has failed. The mechanism is extremely naive and makes several assumptions which are often not correct. Currently, however, it drastically reduces the number of tests that must be skipped in the Nix CI. Test plan: - CI
64 lines
1.7 KiB
C++
64 lines
1.7 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifdef __x86_64__
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extern "C" {
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#include <sys/user.h>
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}
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#include "Arch.h"
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namespace oi::detail::arch {
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std::optional<uintptr_t> getReturnValueAddress(const user_regs_struct& regs) {
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return regs.rax;
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}
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void setProgramCounter(user_regs_struct& regs, uintptr_t pc) {
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regs.rip = pc;
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}
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std::optional<uintptr_t> naiveReadArgument(const user_regs_struct& regs,
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uint8_t idx) {
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/*
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* This function is based on the information available at
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* http://6.s081.scripts.mit.edu/sp18/x86-64-architecture-guide.html. I have
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* no idea under which conditions these registers are selected. We rely on the
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* fact that OID will safely exit if incorrect, potentially producing some
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* incorrect data but otherwise leaving the process unharmed.
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*/
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switch (idx) {
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case 0:
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return regs.rdi;
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case 1:
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return regs.rsi;
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case 2:
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return regs.rdx;
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case 3:
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return regs.rcx;
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case 4:
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return regs.r8;
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case 5:
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return regs.r9;
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default:
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return std::nullopt;
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}
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}
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} // namespace oi::detail::arch
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#endif
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