[Lldb-commits] [lldb] Don't search for separate debug files for mach-o object files (PR #81041)

[via lldb-commits]

https://github.com/jimingham created https://github.com/llvm/llvm-project/pull/81041

mach-o object files never have separate debug info, and in a big app there can be quite a large number of object files, so even a few stats per object file can slow launches considerably.
This patch avoids this search for Mach-o symbol files of object type.

I don't have a way to test this, the only effect is that you didn't do a bunch of stats that weren't going to do any good anyway.

>From 787d48cd3e2af5478f05986268e91d1bfb5a4c30 Mon Sep 17 00:00:00 2001
From: Jim Ingham <jingham at apple.com>
Date: Wed, 7 Feb 2024 13:00:55 -0800
Subject: [PATCH] Don't search for separate debug files for mach-o object files

mach-o object files never have separate debug info, and in a big app
there can be quite a large number of object files, so even a few stats
per object file can slow launches considerably.
This patch avoids this search for Mach-o symbol files of object type.

I don't have a way to test this, the only effect is that you didn't do
a bunch of stats that weren't going to do any good anyway.
---
 .../Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp    | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp b/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
index 47fe0020ce18d..4080a31224a41 100644
--- a/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
+++ b/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
@@ -118,7 +118,13 @@ SymbolVendorMacOSX::CreateInstance(const lldb::ModuleSP &module_sp,
     FileSpec dsym_fspec(module_sp->GetSymbolFileFileSpec());
 
     ObjectFileSP dsym_objfile_sp;
-    if (!dsym_fspec) {
+    // On Darwin, we store the debug information either in object files,
+    // using the debug map to tie them to the executable, or in a dSYM.  We
+    // pass through this routine both for binaries and for .o files, but in the
+    // latter case there will never be an external debug file.  So we shouldn't
+    // do all the stats needed to find it.
+    if (!dsym_fspec && module_sp->GetObjectFile()->CalculateType() 
+        != ObjectFile::eTypeObjectFile) {
       // No symbol file was specified in the module, lets try and find one
       // ourselves.
       FileSpec file_spec = obj_file->GetFileSpec();