[llvm] Reduce llvm-gsymutil memory usage (PR #91023)

[Kamau Bridgeman via llvm-commits]

kamaub wrote:

It seems this commit caused a build failure on the [clang-ppc64le-linux-multistage](https://lab.llvm.org/buildbot/#/builders/76) build no.[583](https://lab.llvm.org/buildbot/#/builders/76/builds/583).

Please take a look at it and post a fix or revert your patch if the fix will take to long to implement. Let me know if there is anyway help or extra information I can offer.
```
FAILED: lib/libLLVMDebugInfoDWARF.so.19.0git 
: && /usr/lib64/ccache/c++ -fPIC -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete   -Wl,-rpath-link,/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/./lib  -Wl,--gc-sections -shared -Wl,-soname,libLLVMDebugInfoDWARF.so.19.0git -o lib/libLLVMDebugInfoDWARF.so.19.0git lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFAbbreviationDeclaration.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFAddressRange.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFAcceleratorTable.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFCompileUnit.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFContext.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDataExtractor.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugAbbrev.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugAddr.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugArangeSet.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugAranges.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugFrame.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFTypePrinter.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugInfoEntry.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugLine.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugLoc.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugMacro.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugPubTable.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugRangeList.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDebugRnglists.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFDie.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFExpression.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFFormValue.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFGdbIndex.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFListTable.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFLocationExpression.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFTypeUnit.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFUnitIndex.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFUnit.cpp.o lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFVerifier.cpp.o  -Wl,-rpath,"\$ORIGIN/../lib:/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib:"  lib/libLLVMObject.so.19.0git  lib/libLLVMBinaryFormat.so.19.0git  lib/libLLVMTargetParser.so.19.0git  lib/libLLVMSupport.so.19.0git  -Wl,-rpath-link,/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-multistage-test/clang-ppc64le-multistage/stage1/lib && :
lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFUnit.cpp.o: In function `DoubleCheckedRWLocker(llvm::sys::SmartRWMutex<false>&, std::function<bool ()> const&, std::function<void ()> const&)':
DWARFUnit.cpp:(.text._ZL21DoubleCheckedRWLockerRN4llvm3sys12SmartRWMutexILb0EEERKSt8functionIFbvEERKS4_IFvvEE+0x44): undefined reference to `pthread_rwlock_rdlock'
DWARFUnit.cpp:(.text._ZL21DoubleCheckedRWLockerRN4llvm3sys12SmartRWMutexILb0EEERKSt8functionIFbvEERKS4_IFvvEE+0x94): undefined reference to `pthread_rwlock_unlock'
DWARFUnit.cpp:(.text._ZL21DoubleCheckedRWLockerRN4llvm3sys12SmartRWMutexILb0EEERKSt8functionIFbvEERKS4_IFvvEE+0xa8): undefined reference to `pthread_rwlock_wrlock'
DWARFUnit.cpp:(.text._ZL21DoubleCheckedRWLockerRN4llvm3sys12SmartRWMutexILb0EEERKSt8functionIFbvEERKS4_IFvvEE+0x114): undefined reference to `pthread_rwlock_unlock'
lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFUnit.cpp.o: In function `llvm::DWARFUnit::tryExtractDIEsIfNeeded(bool) [clone .localalias.18]':
DWARFUnit.cpp:(.text._ZN4llvm9DWARFUnit22tryExtractDIEsIfNeededEb+0x44): undefined reference to `pthread_rwlock_rdlock'
DWARFUnit.cpp:(.text._ZN4llvm9DWARFUnit22tryExtractDIEsIfNeededEb+0x94): undefined reference to `pthread_rwlock_unlock'
lib/DebugInfo/DWARF/CMakeFiles/LLVMDebugInfoDWARF.dir/DWARFUnit.cpp.o: In function `llvm::DWARFUnit::clearDIEs(bool) [clone .localalias.15]':
DWARFUnit.cpp:(.text._ZN4llvm9DWARFUnit9clearDIEsEb+0x30): undefined reference to `pthread_rwlock_wrlock'
DWARFUnit.cpp:(.text._ZN4llvm9DWARFUnit9clearDIEsEb+0x7c): undefined reference to `pthread_rwlock_unlock'
collect2: error: ld returned 1 exit status
```

https://github.com/llvm/llvm-project/pull/91023