Don't search for separate debug files for mach-o object files

[jimingham]

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.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: None (jimingham)

Changes

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.

---

Full diff: https://github.com/llvm/llvm-project/pull/81041.diff

1 Files Affected:

• (modified) lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp (+7-1)

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();

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 369b82218419a0218400e7483255523b8dfd6cf0 b2e7c7e8b342e13b457dcf7da40040f2373c7a3d -- lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp

View the diff from clang-format here.

diff --git a/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp b/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
index f46bff8f7d..70228f0643 100644
--- a/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
+++ b/lldb/source/Plugins/SymbolVendor/MacOSX/SymbolVendorMacOSX.cpp
@@ -124,7 +124,7 @@ SymbolVendorMacOSX::CreateInstance(const lldb::ModuleSP &module_sp,
     // 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) {
+                           ObjectFile::eTypeObjectFile) {
       // No symbol file was specified in the module, lets try and find one
       // ourselves.
       FileSpec file_spec = obj_file->GetFileSpec();

[jasonmolenda]

LGTM.

[adrian-prantl]

Does "external debug file" in this context mean dwo?

[adrian-prantl]

OK I think I get it. This is looking up a dSYM by UUID.
LGTM