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[DWARF] Speedup .gdb_index dumping #151806

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Merged
merged 7 commits into from
Aug 7, 2025
Merged

[DWARF] Speedup .gdb_index dumping #151806

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0d22a6f
[DWARF] Speedup .gdb_index dumping
itrofimow Aug 2, 2025
4d30a5c
cr fixes
itrofimow Aug 6, 2025
72ff5d8
cleanup
itrofimow Aug 6, 2025
9601b2f
clang-format fixes
itrofimow Aug 6, 2025
b51c223
clang-format fixes
itrofimow Aug 6, 2025
ab33820
Merge branch 'main' into llvm_dwarfdump_gdb_index_speedup
itrofimow Aug 6, 2025
6abe831
switch the implementation to binary search instead
itrofimow Aug 6, 2025
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25 changes: 20 additions & 5 deletions llvm/lib/DebugInfo/DWARF/DWARFGdbIndex.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
#include <cinttypes>
#include <cstdint>
#include <set>
#include <unordered_map>
#include <utility>

using namespace llvm;
Expand Down Expand Up @@ -60,6 +61,24 @@ void DWARFGdbIndex::dumpSymbolTable(raw_ostream &OS) const {
", filled slots:",
SymbolTableOffset, (uint64_t)SymbolTable.size())
<< '\n';

std::unordered_map<uint32_t, decltype(ConstantPoolVectors)::const_iterator>
CuVectorMap{};
CuVectorMap.reserve(ConstantPoolVectors.size());
const auto FindCuVector =
[&CuVectorMap, notFound = ConstantPoolVectors.end()](uint32_t vecOffset) {
const auto it = CuVectorMap.find(vecOffset);
if (it != CuVectorMap.end()) {
return it->second;
}

return notFound;
};
for (auto it = ConstantPoolVectors.begin(); it != ConstantPoolVectors.end();
++it) {
CuVectorMap.emplace(it->first, it);
}
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Could drop the {} here.

Could use a range-based for loop, and instead of putting iterators as values in the map, use pointers (then you can get a pointer to the value in the range based for loop where there aren't any visible/name-able iterators)

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I've rearranged the code a bit to just hold the ids in the map, instead of calculating these ids later


uint32_t I = -1;
for (const SymTableEntry &E : SymbolTable) {
++I;
Expand All @@ -72,11 +91,7 @@ void DWARFGdbIndex::dumpSymbolTable(raw_ostream &OS) const {
StringRef Name = ConstantPoolStrings.substr(
ConstantPoolOffset - StringPoolOffset + E.NameOffset);

auto CuVector = llvm::find_if(
ConstantPoolVectors,
[&](const std::pair<uint32_t, SmallVector<uint32_t, 0>> &V) {
return V.first == E.VecOffset;
});
auto CuVector = FindCuVector(E.VecOffset);
assert(CuVector != ConstantPoolVectors.end() && "Invalid symbol table");
uint32_t CuVectorId = CuVector - ConstantPoolVectors.begin();
OS << format(" String name: %s, CU vector index: %d\n", Name.data(),
Expand Down
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