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[debugserver] Add platform cache support to improve performance. 

The dyld SPI used by debugserver (_dyld_process_info_create) has become
much slower in macOS BigSur 11.3 causing a significant performance
regression when attaching. This commit mitigates that by caching the
result when calling the SPI to compute the platform.

Differential revision: https://reviews.llvm.org/D102833
This commit is contained in:
kuperxu 2021-05-20 19:05:16 -07:00 committed by Jonas Devlieghere
parent a888e492f6
commit 8dd106028b
2 changed files with 13 additions and 3 deletions
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2
lldb/tools/debugserver/source/MacOSX/MachProcess.h
View File

@ -252,6 +252,7 @@ public:
struct mach_o_information &inf);
JSONGenerator::ObjectSP FormatDynamicLibrariesIntoJSON(
const std::vector<struct binary_image_information> &image_infos);
uint32_t GetPlatform();
/// Get the runtime platform from DYLD via SPI.
uint32_t GetProcessPlatformViaDYLDSPI();
/// Use the dyld SPI present in macOS 10.12, iOS 10, tvOS 10,
@ -378,6 +379,7 @@ private:
pid_t m_pid; // Process ID of child process
cpu_type_t m_cpu_type; // The CPU type of this process
uint32_t m_platform; // The platform of this process
int m_child_stdin;
int m_child_stdout;
int m_child_stderr;

14
lldb/tools/debugserver/source/MacOSX/MachProcess.mm
View File

@ -701,7 +701,7 @@ MachProcess::GetDeploymentInfo(const struct load_command &lc,
// DYLD_FORCE_PLATFORM=6. In that case, force the platform to
// macCatalyst and use the macCatalyst version of the host OS
// instead of the macOS deployment target.
if (is_executable && GetProcessPlatformViaDYLDSPI() == PLATFORM_MACCATALYST) {
if (is_executable && GetPlatform() == PLATFORM_MACCATALYST) {
info.platform = PLATFORM_MACCATALYST;
std::string catalyst_version = GetMacCatalystVersionString();
const char *major = catalyst_version.c_str();
@ -1094,6 +1094,12 @@ struct dyld_process_cache_info {
bool privateCache;
};
uint32_t MachProcess::GetPlatform() {
if (m_platform == 0)
m_platform = MachProcess::GetProcessPlatformViaDYLDSPI();
return m_platform;
}
uint32_t MachProcess::GetProcessPlatformViaDYLDSPI() {
kern_return_t kern_ret;
uint32_t platform = 0;
@ -1140,7 +1146,7 @@ MachProcess::GetAllLoadedLibrariesInfos(nub_process_t pid) {
int pointer_size = GetInferiorAddrSize(pid);
std::vector<struct binary_image_information> image_infos;
GetAllLoadedBinariesViaDYLDSPI(image_infos);
uint32_t platform = GetProcessPlatformViaDYLDSPI();
uint32_t platform = GetPlatform();
const size_t image_count = image_infos.size();
for (size_t i = 0; i < image_count; i++) {
GetMachOInformationFromMemory(platform, image_infos[i].load_address,
@ -1160,7 +1166,7 @@ JSONGenerator::ObjectSP MachProcess::GetLibrariesInfoForAddresses(
std::vector<struct binary_image_information> all_image_infos;
GetAllLoadedBinariesViaDYLDSPI(all_image_infos);
uint32_t platform = GetProcessPlatformViaDYLDSPI();
uint32_t platform = GetPlatform();
std::vector<struct binary_image_information> image_infos;
const size_t macho_addresses_count = macho_addresses.size();
@ -1324,6 +1330,7 @@ void MachProcess::Clear(bool detaching) {
// Clear any cached thread list while the pid and task are still valid
m_task.Clear();
m_platform = 0;
// Now clear out all member variables
m_pid = INVALID_NUB_PROCESS;
if (!detaching)
@ -1615,6 +1622,7 @@ bool MachProcess::Detach() {
// NULL our task out as we have already restored all exception ports
m_task.Clear();
m_platform = 0;
// Clear out any notion of the process we once were
const bool detaching = true;