[Lldb-commits] [PATCH] D15978: Prevent infinite recursive loop in AppleObjCTrampolineHandler constructor

[Francis Ricci via lldb-commits]

fjricci created this revision.
fjricci added reviewers: clayborg, jingham.
fjricci added subscribers: lldb-commits, sas.

When we construct AppleObjCTrampolineHandler, if m_impl_fn_addr is invalid, we 
call CanJIT(). If the gdb remote process does not support allocating and 
deallocating memory, this call stack will include a call to the 
AppleObjCRuntime constructor. The AppleObjCRuntime constructor will then call 
the AppleObjCTrampolineHandler constructor, creating a recursive call loop that 
eventually overflows the stack and segfaults.

Avoid this call loop by not constructing the AppleObjCTrampolineHandler within 
AppleObjCRuntime until we actually need to use it.

http://reviews.llvm.org/D15978

Files:
  source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp

Index: source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
===================================================================
--- source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
+++ source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
@@ -50,7 +50,6 @@
     m_objc_trampoline_handler_ap (),
     m_Foundation_major()
 {
-    ReadObjCLibraryIfNeeded (process->GetTarget().GetImages());
 }
 
 bool
@@ -76,6 +75,7 @@
 bool
 AppleObjCRuntime::GetObjectDescription (Stream &strm, Value &value, 
ExecutionContextScope *exe_scope)
 {
+    ReadObjCLibraryIfNeeded (m_process->GetTarget().GetImages());
     if (!m_read_objc_library)
         return false;
         
@@ -369,6 +369,7 @@
 AppleObjCRuntime::GetStepThroughTrampolinePlan (Thread &thread, bool 
stop_others)
 {
     ThreadPlanSP thread_plan_sp;
+    ReadObjCLibraryIfNeeded (m_process->GetTarget().GetImages());
     if (m_objc_trampoline_handler_ap.get())
         thread_plan_sp = 
m_objc_trampoline_handler_ap->GetStepThroughDispatchPlan (thread, stop_others);
     return thread_plan_sp;



Index: source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
===================================================================
--- source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
+++ source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntime.cpp
@@ -50,7 +50,6 @@
     m_objc_trampoline_handler_ap (),
     m_Foundation_major()
 {
-    ReadObjCLibraryIfNeeded (process->GetTarget().GetImages());
 }
 
 bool
@@ -76,6 +75,7 @@
 bool
 AppleObjCRuntime::GetObjectDescription (Stream &strm, Value &value, ExecutionContextScope *exe_scope)
 {
+    ReadObjCLibraryIfNeeded (m_process->GetTarget().GetImages());
     if (!m_read_objc_library)
         return false;
         
@@ -369,6 +369,7 @@
 AppleObjCRuntime::GetStepThroughTrampolinePlan (Thread &thread, bool stop_others)
 {
     ThreadPlanSP thread_plan_sp;
+    ReadObjCLibraryIfNeeded (m_process->GetTarget().GetImages());
     if (m_objc_trampoline_handler_ap.get())
         thread_plan_sp = m_objc_trampoline_handler_ap->GetStepThroughDispatchPlan (thread, stop_others);
     return thread_plan_sp;

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