[Lldb-commits] [lldb] r357276 - Use the multi-lockable form of std::lock for operator=
Jim Ingham via lldb-commits
lldb-commits at lists.llvm.org
Fri Mar 29 10:07:30 PDT 2019
Author: jingham
Date: Fri Mar 29 10:07:30 2019
New Revision: 357276
URL: http://llvm.org/viewvc/llvm-project?rev=357276&view=rev
Log:
Use the multi-lockable form of std::lock for operator=
For = operators for lists that have mutexes, we were either
just taking the locks sequentially or hand-rolling a trick
to try to avoid lock inversion. Use the std::lock mechanism
for this instead.
Differential Revision: https://reviews.llvm.org/D59957
Modified:
lldb/trunk/include/lldb/Core/ModuleSpec.h
lldb/trunk/include/lldb/Utility/StreamTee.h
lldb/trunk/source/Breakpoint/BreakpointLocationCollection.cpp
lldb/trunk/source/Core/ModuleList.cpp
lldb/trunk/source/Target/SectionLoadList.cpp
lldb/trunk/source/Target/ThreadList.cpp
Modified: lldb/trunk/include/lldb/Core/ModuleSpec.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Core/ModuleSpec.h?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Core/ModuleSpec.h (original)
+++ lldb/trunk/include/lldb/Core/ModuleSpec.h Fri Mar 29 10:07:30 2019
@@ -311,8 +311,10 @@ public:
ModuleSpecList &operator=(const ModuleSpecList &rhs) {
if (this != &rhs) {
- std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex);
- std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex);
+ std::lock(m_mutex, rhs.m_mutex);
+ std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex, std::adopt_lock);
+ std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex,
+ std::adopt_lock);
m_specs = rhs.m_specs;
}
return *this;
Modified: lldb/trunk/include/lldb/Utility/StreamTee.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Utility/StreamTee.h?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/include/lldb/Utility/StreamTee.h (original)
+++ lldb/trunk/include/lldb/Utility/StreamTee.h Fri Mar 29 10:07:30 2019
@@ -49,8 +49,11 @@ public:
StreamTee &operator=(const StreamTee &rhs) {
if (this != &rhs) {
Stream::operator=(rhs);
- std::lock_guard<std::recursive_mutex> lhs_locker(m_streams_mutex);
- std::lock_guard<std::recursive_mutex> rhs_locker(rhs.m_streams_mutex);
+ std::lock(m_streams_mutex, rhs.m_streams_mutex);
+ std::lock_guard<std::recursive_mutex> lhs_locker(m_streams_mutex,
+ std::adopt_lock);
+ std::lock_guard<std::recursive_mutex> rhs_locker(rhs.m_streams_mutex,
+ std::adopt_lock);
m_streams = rhs.m_streams;
}
return *this;
Modified: lldb/trunk/source/Breakpoint/BreakpointLocationCollection.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Breakpoint/BreakpointLocationCollection.cpp?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/source/Breakpoint/BreakpointLocationCollection.cpp (original)
+++ lldb/trunk/source/Breakpoint/BreakpointLocationCollection.cpp Fri Mar 29 10:07:30 2019
@@ -181,17 +181,11 @@ void BreakpointLocationCollection::GetDe
BreakpointLocationCollection &BreakpointLocationCollection::operator=(
const BreakpointLocationCollection &rhs) {
- // Same trick as in ModuleList to avoid lock inversion.
if (this != &rhs) {
- if (uintptr_t(this) > uintptr_t(&rhs)) {
- std::lock_guard<std::mutex> lhs_guard(m_collection_mutex);
- std::lock_guard<std::mutex> rhs_guard(rhs.m_collection_mutex);
+ std::lock(m_collection_mutex, rhs.m_collection_mutex);
+ std::lock_guard<std::mutex> lhs_guard(m_collection_mutex, std::adopt_lock);
+ std::lock_guard<std::mutex> rhs_guard(rhs.m_collection_mutex, std::adopt_lock);
m_break_loc_collection = rhs.m_break_loc_collection;
- } else {
- std::lock_guard<std::mutex> lhs_guard(m_collection_mutex);
- std::lock_guard<std::mutex> rhs_guard(rhs.m_collection_mutex);
- m_break_loc_collection = rhs.m_break_loc_collection;
- }
}
return *this;
}
Modified: lldb/trunk/source/Core/ModuleList.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/ModuleList.cpp?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/source/Core/ModuleList.cpp (original)
+++ lldb/trunk/source/Core/ModuleList.cpp Fri Mar 29 10:07:30 2019
@@ -130,25 +130,12 @@ ModuleList::ModuleList(ModuleList::Notif
const ModuleList &ModuleList::operator=(const ModuleList &rhs) {
if (this != &rhs) {
- // That's probably me nit-picking, but in theoretical situation:
- //
- // * that two threads A B and
- // * two ModuleList's x y do opposite assignments ie.:
- //
- // in thread A: | in thread B:
- // x = y; | y = x;
- //
- // This establishes correct(same) lock taking order and thus avoids
- // priority inversion.
- if (uintptr_t(this) > uintptr_t(&rhs)) {
- std::lock_guard<std::recursive_mutex> lhs_guard(m_modules_mutex);
- std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_modules_mutex);
- m_modules = rhs.m_modules;
- } else {
- std::lock_guard<std::recursive_mutex> lhs_guard(m_modules_mutex);
- std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_modules_mutex);
- m_modules = rhs.m_modules;
- }
+ std::lock(m_modules_mutex, rhs.m_modules_mutex);
+ std::lock_guard<std::recursive_mutex> lhs_guard(m_modules_mutex,
+ std::adopt_lock);
+ std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_modules_mutex,
+ std::adopt_lock);
+ m_modules = rhs.m_modules;
}
return *this;
}
Modified: lldb/trunk/source/Target/SectionLoadList.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/SectionLoadList.cpp?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/source/Target/SectionLoadList.cpp (original)
+++ lldb/trunk/source/Target/SectionLoadList.cpp Fri Mar 29 10:07:30 2019
@@ -27,8 +27,9 @@ SectionLoadList::SectionLoadList(const S
}
void SectionLoadList::operator=(const SectionLoadList &rhs) {
- std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex);
- std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex);
+ std::lock(m_mutex, rhs.m_mutex);
+ std::lock_guard<std::recursive_mutex> lhs_guard(m_mutex, std::adopt_lock);
+ std::lock_guard<std::recursive_mutex> rhs_guard(rhs.m_mutex, std::adopt_lock);
m_addr_to_sect = rhs.m_addr_to_sect;
m_sect_to_addr = rhs.m_sect_to_addr;
}
Modified: lldb/trunk/source/Target/ThreadList.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/ThreadList.cpp?rev=357276&r1=357275&r2=357276&view=diff
==============================================================================
--- lldb/trunk/source/Target/ThreadList.cpp (original)
+++ lldb/trunk/source/Target/ThreadList.cpp Fri Mar 29 10:07:30 2019
@@ -37,8 +37,10 @@ const ThreadList &ThreadList::operator=(
if (this != &rhs) {
// Lock both mutexes to make sure neither side changes anyone on us while
// the assignment occurs
- std::lock_guard<std::recursive_mutex> guard(GetMutex());
- std::lock_guard<std::recursive_mutex> rhs_guard(rhs.GetMutex());
+ std::lock(GetMutex(), rhs.GetMutex());
+ std::lock_guard<std::recursive_mutex> guard(GetMutex(), std::adopt_lock);
+ std::lock_guard<std::recursive_mutex> rhs_guard(rhs.GetMutex(),
+ std::adopt_lock);
m_process = rhs.m_process;
m_stop_id = rhs.m_stop_id;
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