sgraenitz created this revision.
sgraenitz added reviewers: jasonmolenda, jingham, bulbazord, aprantl.
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We added support for the GNUstep ObjC runtime in 0b6264738f3d
<https://reviews.llvm.org/rG0b6264738f3d3688719b23c5d272725d3d9bf4e0>. In order
to check if the target process uses
GNUstep we run an expensive symbol lookup in `CreateInstance()`. This turned
out to cause a heavy performance
regression for non-GNUstep inferiors.
This patch puts a cheaper check in front, so that the vast majority of requests
should return early. This
should fix the symptom for the moment. The conceptual question is why
`LanguageRuntime::FindPlugin` invokes
`create_callback` for each available runtime unconditionally in every
`Process::ModulesDidLoad`.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D158205
Files:
lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
Index:
lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
===================================================================
---
lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
+++
lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
@@ -37,6 +37,33 @@
PluginManager::UnregisterPlugin(CreateInstance);
}
+static bool CanModuleBeGNUstepObjCLibrary(const ModuleSP &module_sp,
+ const llvm::Triple &TT) {
+ if (!module_sp)
+ return false;
+ const FileSpec &module_file_spec = module_sp->GetFileSpec();
+ if (!module_file_spec)
+ return false;
+ llvm::StringRef filename = module_file_spec.GetFilename().GetStringRef();
+ if (TT.isOSBinFormatELF())
+ return filename.starts_with("libobjc.so");
+ if (TT.isOSWindows())
+ return filename == "objc.dll";
+ return false;
+}
+
+static bool ScanForGNUstepObjCLibraryCandidate(const ModuleList &modules,
+ const llvm::Triple &TT) {
+ std::lock_guard<std::recursive_mutex> guard(modules.GetMutex());
+ size_t num_modules = modules.GetSize();
+ for (size_t i = 0; i < num_modules; i++) {
+ auto mod = modules.GetModuleAtIndex(i);
+ if (CanModuleBeGNUstepObjCLibrary(mod, TT))
+ return true;
+ }
+ return false;
+}
+
LanguageRuntime *GNUstepObjCRuntime::CreateInstance(Process *process,
LanguageType language) {
if (language != eLanguageTypeObjC)
@@ -50,6 +77,9 @@
return nullptr;
const ModuleList &images = target.GetImages();
+ if (!ScanForGNUstepObjCLibraryCandidate(images, TT))
+ return nullptr;
+
if (TT.isOSBinFormatELF()) {
SymbolContextList eh_pers;
RegularExpression regex("__gnustep_objc[x]*_personality_v[0-9]+");
@@ -176,18 +206,8 @@
}
bool GNUstepObjCRuntime::IsModuleObjCLibrary(const ModuleSP &module_sp) {
- if (!module_sp)
- return false;
- const FileSpec &module_file_spec = module_sp->GetFileSpec();
- if (!module_file_spec)
- return false;
- llvm::StringRef filename = module_file_spec.GetFilename().GetStringRef();
const llvm::Triple &TT = GetTargetRef().GetArchitecture().GetTriple();
- if (TT.isOSBinFormatELF())
- return filename.starts_with("libobjc.so");
- if (TT.isOSWindows())
- return filename == "objc.dll";
- return false;
+ return CanModuleBeGNUstepObjCLibrary(module_sp, TT);
}
bool GNUstepObjCRuntime::ReadObjCLibrary(const ModuleSP &module_sp) {
Index: lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
===================================================================
--- lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
+++ lldb/source/Plugins/LanguageRuntime/ObjC/GNUstepObjCRuntime/GNUstepObjCRuntime.cpp
@@ -37,6 +37,33 @@
PluginManager::UnregisterPlugin(CreateInstance);
}
+static bool CanModuleBeGNUstepObjCLibrary(const ModuleSP &module_sp,
+ const llvm::Triple &TT) {
+ if (!module_sp)
+ return false;
+ const FileSpec &module_file_spec = module_sp->GetFileSpec();
+ if (!module_file_spec)
+ return false;
+ llvm::StringRef filename = module_file_spec.GetFilename().GetStringRef();
+ if (TT.isOSBinFormatELF())
+ return filename.starts_with("libobjc.so");
+ if (TT.isOSWindows())
+ return filename == "objc.dll";
+ return false;
+}
+
+static bool ScanForGNUstepObjCLibraryCandidate(const ModuleList &modules,
+ const llvm::Triple &TT) {
+ std::lock_guard<std::recursive_mutex> guard(modules.GetMutex());
+ size_t num_modules = modules.GetSize();
+ for (size_t i = 0; i < num_modules; i++) {
+ auto mod = modules.GetModuleAtIndex(i);
+ if (CanModuleBeGNUstepObjCLibrary(mod, TT))
+ return true;
+ }
+ return false;
+}
+
LanguageRuntime *GNUstepObjCRuntime::CreateInstance(Process *process,
LanguageType language) {
if (language != eLanguageTypeObjC)
@@ -50,6 +77,9 @@
return nullptr;
const ModuleList &images = target.GetImages();
+ if (!ScanForGNUstepObjCLibraryCandidate(images, TT))
+ return nullptr;
+
if (TT.isOSBinFormatELF()) {
SymbolContextList eh_pers;
RegularExpression regex("__gnustep_objc[x]*_personality_v[0-9]+");
@@ -176,18 +206,8 @@
}
bool GNUstepObjCRuntime::IsModuleObjCLibrary(const ModuleSP &module_sp) {
- if (!module_sp)
- return false;
- const FileSpec &module_file_spec = module_sp->GetFileSpec();
- if (!module_file_spec)
- return false;
- llvm::StringRef filename = module_file_spec.GetFilename().GetStringRef();
const llvm::Triple &TT = GetTargetRef().GetArchitecture().GetTriple();
- if (TT.isOSBinFormatELF())
- return filename.starts_with("libobjc.so");
- if (TT.isOSWindows())
- return filename == "objc.dll";
- return false;
+ return CanModuleBeGNUstepObjCLibrary(module_sp, TT);
}
bool GNUstepObjCRuntime::ReadObjCLibrary(const ModuleSP &module_sp) {
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