clayborg created this revision.
clayborg added reviewers: labath, JDevlieghere, yinghuitan.
Herald added a project: All.
clayborg requested review of this revision.
Herald added a project: LLDB.
Herald added a subscriber: lldb-commits.
Prior to this fix, no shared libraries would be loaded for a core file, even if
they exist on the current machine. The issue was the DYLDRendezvous would read
a DYLDRendezvous::Rendezvous from memory of the process in
DYLDRendezvous::Resolve() which would read some ld.so structures as they
existed in the middle of a process' lifetime. In core files we see, the
DYLDRendezvous::Rendezvous::state would be set to eAdd for running processes.
When ProcessELFCore.cpp would load the core file, it would call
DynamicLoaderPOSIXDYLD::DidAttach(), which would call the above Rendezvous
functions. The issue came when during the DidAttach function it call
DYLDRendezvous::GetAction() which would return eNoAction if the
DYLDRendezvous::m_current.state was read from memory as eAdd. This caused no
shared libraries to be loaded for any ELF core files. We now detect if we have
a core file and after reading the DYLDRendezvous::m_current.state from memory
we set it to eConsistent, which causes DYLDRendezvous::GetAction() to return
the correct action of eTakeSnapshot and shared libraries get loaded.
We also improve the DynamicLoaderPOSIXDYLD class to not try and set any
breakpoints to catch shared library loads/unloads when we have a core file,
which saves a bit of time.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D134842
Files:
lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
@@ -91,6 +91,9 @@
std::map<lldb::ModuleWP, lldb::addr_t, std::owner_less<lldb::ModuleWP>>
m_loaded_modules;
+ /// Returns true if the process is for a core file.
+ bool IsCoreFile() const;
+
/// If possible sets a breakpoint on a function called by the runtime
/// linker each time a module is loaded or unloaded.
bool SetRendezvousBreakpoint();
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -213,6 +213,10 @@
void DynamicLoaderPOSIXDYLD::ProbeEntry() {
Log *log = GetLog(LLDBLog::DynamicLoader);
+ // If we have a core file, we don't need any breakpoints.
+ if (IsCoreFile())
+ return;
+
const addr_t entry = GetEntryPoint();
if (entry == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(
@@ -297,6 +301,11 @@
bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
Log *log = GetLog(LLDBLog::DynamicLoader);
+
+ // If we have a core file, we don't need any breakpoints.
+ if (IsCoreFile())
+ return false;
+
if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
LLDB_LOG(log,
"Rendezvous breakpoint breakpoint id {0} for pid {1}"
@@ -829,3 +838,7 @@
return module_sp->GetFileSpec().GetPath() == "[vdso]";
}
+
+bool DynamicLoaderPOSIXDYLD::IsCoreFile() const {
+ return !m_process->IsLiveDebugSession();
+}
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
@@ -267,6 +267,8 @@
bool FindMetadata(const char *name, PThreadField field, uint32_t &value);
+ bool IsCoreFile() const;
+
enum RendezvousAction {
eNoAction,
eTakeSnapshot,
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
@@ -171,6 +171,15 @@
if (!(cursor = ReadPointer(cursor + padding, &info.ldbase)))
return false;
+ // If we have a core file, we will read the current rendezvous state
+ // from the core file's memory which will indicate there is nothing
+ // to do, but we need it to load all of the shared libraries. If we
+ // don't change this, then "info.state" will be set to eAdd and the
+ // m_previous.state will be eConsistent and GetAction() will return
+ // eNoAction when we need it to return eTakeSnapshot.
+ if (IsCoreFile())
+ info.state = eConsistent;
+
// The rendezvous was successfully read. Update our internal state.
m_rendezvous_addr = info_addr;
m_previous = m_current;
@@ -664,3 +673,7 @@
LLDB_LOGF(log, " Prev : %" PRIx64, I->prev);
}
}
+
+bool DYLDRendezvous::IsCoreFile() const {
+ return !m_process->IsLiveDebugSession();
+}
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.h
@@ -91,6 +91,9 @@
std::map<lldb::ModuleWP, lldb::addr_t, std::owner_less<lldb::ModuleWP>>
m_loaded_modules;
+ /// Returns true if the process is for a core file.
+ bool IsCoreFile() const;
+
/// If possible sets a breakpoint on a function called by the runtime
/// linker each time a module is loaded or unloaded.
bool SetRendezvousBreakpoint();
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DynamicLoaderPOSIXDYLD.cpp
@@ -213,6 +213,10 @@
void DynamicLoaderPOSIXDYLD::ProbeEntry() {
Log *log = GetLog(LLDBLog::DynamicLoader);
+ // If we have a core file, we don't need any breakpoints.
+ if (IsCoreFile())
+ return;
+
const addr_t entry = GetEntryPoint();
if (entry == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(
@@ -297,6 +301,11 @@
bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
Log *log = GetLog(LLDBLog::DynamicLoader);
+
+ // If we have a core file, we don't need any breakpoints.
+ if (IsCoreFile())
+ return false;
+
if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
LLDB_LOG(log,
"Rendezvous breakpoint breakpoint id {0} for pid {1}"
@@ -829,3 +838,7 @@
return module_sp->GetFileSpec().GetPath() == "[vdso]";
}
+
+bool DynamicLoaderPOSIXDYLD::IsCoreFile() const {
+ return !m_process->IsLiveDebugSession();
+}
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.h
@@ -267,6 +267,8 @@
bool FindMetadata(const char *name, PThreadField field, uint32_t &value);
+ bool IsCoreFile() const;
+
enum RendezvousAction {
eNoAction,
eTakeSnapshot,
Index: lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
===================================================================
--- lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
+++ lldb/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp
@@ -171,6 +171,15 @@
if (!(cursor = ReadPointer(cursor + padding, &info.ldbase)))
return false;
+ // If we have a core file, we will read the current rendezvous state
+ // from the core file's memory which will indicate there is nothing
+ // to do, but we need it to load all of the shared libraries. If we
+ // don't change this, then "info.state" will be set to eAdd and the
+ // m_previous.state will be eConsistent and GetAction() will return
+ // eNoAction when we need it to return eTakeSnapshot.
+ if (IsCoreFile())
+ info.state = eConsistent;
+
// The rendezvous was successfully read. Update our internal state.
m_rendezvous_addr = info_addr;
m_previous = m_current;
@@ -664,3 +673,7 @@
LLDB_LOGF(log, " Prev : %" PRIx64, I->prev);
}
}
+
+bool DYLDRendezvous::IsCoreFile() const {
+ return !m_process->IsLiveDebugSession();
+}
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