Skip to content

[llvm-nm] Improve performance while faking symbols from function starts #162755

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Oct 12, 2025
Merged

[llvm-nm] Improve performance while faking symbols from function starts #162755

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
87e7ec3
[llvm-nm] Improve performance while faking symbols from function starts
drodriguez Oct 10, 2025
6201874
Apply feedback
drodriguez Oct 10, 2025
65815a4
Add explanatory comment about relation between FoundFns and SymbolLis…
drodriguez Oct 10, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 12 additions & 8 deletions llvm/tools/llvm-nm/llvm-nm.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/MachO.h"
Expand Down Expand Up @@ -1615,15 +1616,18 @@ static void dumpSymbolsFromDLInfoMachO(MachOObjectFile &MachO,
}
// See if these addresses are already in the symbol table.
unsigned FunctionStartsAdded = 0;
// The addresses from FoundFns come from LC_FUNCTION_STARTS. Its contents
// are delta encoded addresses from the start of __TEXT, ending when zero
// is found. Because of this, the addresses should be unique, and even if
// we create fake entries on SymbolList in the second loop, SymbolAddresses
// should not need to be updated there.
SmallSet<uint64_t, 32> SymbolAddresses;
for (const auto &S : SymbolList)
SymbolAddresses.insert(S.Address);
for (uint64_t f = 0; f < FoundFns.size(); f++) {
bool found = false;
for (unsigned J = 0; J < SymbolList.size() && !found; ++J) {
if (SymbolList[J].Address == FoundFns[f] + BaseSegmentAddress)
found = true;
}
// See this address is not already in the symbol table fake up an
// nlist for it.
if (!found) {
// See if this address is already in the symbol table, otherwise fake up
// an nlist for it.
if (!SymbolAddresses.contains(FoundFns[f] + BaseSegmentAddress)) {
NMSymbol F = {};
F.Name = "<redacted function X>";
F.Address = FoundFns[f] + BaseSegmentAddress;
Expand Down