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[lldb] Expand background symbol lookup #80890

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Merged
merged 1 commit into from
Feb 8, 2024
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[lldb] Expand background symbol lookup #80890

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23 changes: 22 additions & 1 deletion lldb/include/lldb/Core/ModuleList.h
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,26 @@ class UUID;
class VariableList;
struct ModuleFunctionSearchOptions;

static constexpr OptionEnumValueElement g_auto_download_enum_values[] = {
{
lldb::eSymbolDownloadOff,
"off",
"Disable automatically downloading symbols.",
},
{
lldb::eSymbolDownloadBackground,
"background",
"Download symbols in the background for images as they appear in the "
"backtrace.",
Comment on lines +59 to +60
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Is this truly only for backtraces? Wouldn't an address lookup in a binary also qualify as a way to force debug info to be loaded?

},
{
lldb::eSymbolDownloadForeground,
"foreground",
"Download symbols in the foreground for images as they appear in the "
"backtrace.",
},
};

class ModuleListProperties : public Properties {
mutable llvm::sys::RWMutex m_symlink_paths_mutex;
PathMappingList m_symlink_paths;
Expand All @@ -60,7 +80,6 @@ class ModuleListProperties : public Properties {
bool SetClangModulesCachePath(const FileSpec &path);
bool GetEnableExternalLookup() const;
bool SetEnableExternalLookup(bool new_value);
bool GetEnableBackgroundLookup() const;
bool GetEnableLLDBIndexCache() const;
bool SetEnableLLDBIndexCache(bool new_value);
uint64_t GetLLDBIndexCacheMaxByteSize();
Expand All @@ -71,6 +90,8 @@ class ModuleListProperties : public Properties {

bool GetLoadSymbolOnDemand();

lldb::SymbolDownload GetSymbolAutoDownload() const;

PathMappingList GetSymlinkMappings() const;
};

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6 changes: 6 additions & 0 deletions lldb/include/lldb/lldb-enumerations.h
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Expand Up @@ -1314,6 +1314,12 @@ enum class ChildCacheState {
///< re-use what we computed the last time we called Update.
};

enum SymbolDownload {
eSymbolDownloadOff = 0,
eSymbolDownloadBackground = 1,
eSymbolDownloadForeground = 2,
};

} // namespace lldb

#endif // LLDB_LLDB_ENUMERATIONS_H
7 changes: 6 additions & 1 deletion lldb/source/Core/CoreProperties.td
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Expand Up @@ -8,7 +8,12 @@ let Definition = "modulelist" in {
def EnableBackgroundLookup: Property<"enable-background-lookup", "Boolean">,
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Should we leave this setting around and adapt it to use the new setting with the correct defaults set? If someone has a settings set enable-background-lookup true in their ~/.lldbinit file, this will cause the .lldbinit file to stop executing lines if this setting fails to be set. This is kind of like a backward compatibility in our API kind of thing. We can make this setting as deprecated and tell people to use the download setting instead, but it would be nice if it still worked.

If this was used for dsymForUUID only and there weren't many customers it could be ok to remove, but I would err on the side of caution.

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I was on the fence, as I've been encouraging users to use settings set symbols.enable-background-lookup true in their .lldbinit (because older versions don't know about the setting either). On the other hand it's very little work to keep the old setting working, so why not. I've pushed a commit that makes the old setting an alias.

Global,
DefaultFalse,
Desc<"On macOS, enable calling dsymForUUID (or an equivalent script/binary) in the background to locate symbol files that weren't found.">;
Desc<"Alias for backward compatibility: when enabled this is the equivalent to 'symbols.download background'.">;
def AutoDownload: Property<"auto-download", "Enum">,
Global,
DefaultEnumValue<"eSymbolDownloadOff">,
EnumValues<"OptionEnumValues(g_auto_download_enum_values)">,
Desc<"On macOS, automatically download symbols with dsymForUUID (or an equivalent script/binary) for relevant images in the debug session.">;
def ClangModulesCachePath: Property<"clang-modules-cache-path", "FileSpec">,
Global,
DefaultStringValue<"">,
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13 changes: 9 additions & 4 deletions lldb/source/Core/ModuleList.cpp
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Expand Up @@ -104,10 +104,15 @@ bool ModuleListProperties::SetEnableExternalLookup(bool new_value) {
return SetPropertyAtIndex(ePropertyEnableExternalLookup, new_value);
}

bool ModuleListProperties::GetEnableBackgroundLookup() const {
const uint32_t idx = ePropertyEnableBackgroundLookup;
return GetPropertyAtIndexAs<bool>(
idx, g_modulelist_properties[idx].default_uint_value != 0);
SymbolDownload ModuleListProperties::GetSymbolAutoDownload() const {
// Backward compatibility alias.
if (GetPropertyAtIndexAs<bool>(ePropertyEnableBackgroundLookup, false))
return eSymbolDownloadBackground;

const uint32_t idx = ePropertyAutoDownload;
return GetPropertyAtIndexAs<lldb::SymbolDownload>(
idx, static_cast<lldb::SymbolDownload>(
g_modulelist_properties[idx].default_uint_value));
}

FileSpec ModuleListProperties::GetClangModulesCachePath() const {
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2 changes: 2 additions & 0 deletions lldb/source/Host/common/Host.cpp
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Expand Up @@ -550,6 +550,8 @@ llvm::Error Host::OpenFileInExternalEditor(llvm::StringRef editor,
}

bool Host::IsInteractiveGraphicSession() { return false; }

bool Host::IsNetworkLimited() { return false; }
#endif

std::unique_ptr<Connection> Host::CreateDefaultConnection(llvm::StringRef url) {
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22 changes: 16 additions & 6 deletions lldb/source/Symbol/SymbolLocator.cpp
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Expand Up @@ -10,6 +10,7 @@

#include "lldb/Core/Debugger.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Host/Host.h"

#include "llvm/ADT/SmallSet.h"
#include "llvm/Support/ThreadPool.h"
Expand All @@ -18,12 +19,10 @@ using namespace lldb;
using namespace lldb_private;

void SymbolLocator::DownloadSymbolFileAsync(const UUID &uuid) {
if (!ModuleList::GetGlobalModuleListProperties().GetEnableBackgroundLookup())
return;

static llvm::SmallSet<UUID, 8> g_seen_uuids;
static std::mutex g_mutex;
Debugger::GetThreadPool().async([=]() {

auto lookup = [=]() {
{
std::lock_guard<std::mutex> guard(g_mutex);
if (g_seen_uuids.count(uuid))
Expand All @@ -36,12 +35,23 @@ void SymbolLocator::DownloadSymbolFileAsync(const UUID &uuid) {
module_spec.GetUUID() = uuid;
if (!PluginManager::DownloadObjectAndSymbolFile(module_spec, error,
/*force_lookup=*/true,
/*copy_executable=*/false))
/*copy_executable=*/true))
return;

if (error.Fail())
return;

Debugger::ReportSymbolChange(module_spec);
});
};

switch (ModuleList::GetGlobalModuleListProperties().GetSymbolAutoDownload()) {
case eSymbolDownloadOff:
break;
case eSymbolDownloadBackground:
Debugger::GetThreadPool().async(lookup);
break;
case eSymbolDownloadForeground:
lookup();
break;
};
}