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-rw-r--r--llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp221
1 files changed, 221 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp b/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp
new file mode 100644
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--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp
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+//===- llvm/CodeGen/AsmPrinter/AccelTable.cpp - Accelerator Tables --------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for writing accelerator tables.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/AccelTable.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/DIE.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+#include <vector>
+
+using namespace llvm;
+
+void AppleAccelTableHeader::emit(AsmPrinter *Asm) {
+ // Emit Header.
+ Asm->OutStreamer->AddComment("Header Magic");
+ Asm->EmitInt32(Header.Magic);
+ Asm->OutStreamer->AddComment("Header Version");
+ Asm->EmitInt16(Header.Version);
+ Asm->OutStreamer->AddComment("Header Hash Function");
+ Asm->EmitInt16(Header.HashFunction);
+ Asm->OutStreamer->AddComment("Header Bucket Count");
+ Asm->EmitInt32(Header.BucketCount);
+ Asm->OutStreamer->AddComment("Header Hash Count");
+ Asm->EmitInt32(Header.HashCount);
+ Asm->OutStreamer->AddComment("Header Data Length");
+ Asm->EmitInt32(Header.HeaderDataLength);
+
+ // Emit Header Data
+ Asm->OutStreamer->AddComment("HeaderData Die Offset Base");
+ Asm->EmitInt32(HeaderData.DieOffsetBase);
+ Asm->OutStreamer->AddComment("HeaderData Atom Count");
+ Asm->EmitInt32(HeaderData.Atoms.size());
+
+ for (size_t i = 0; i < HeaderData.Atoms.size(); i++) {
+ Atom A = HeaderData.Atoms[i];
+ Asm->OutStreamer->AddComment(dwarf::AtomTypeString(A.Type));
+ Asm->EmitInt16(A.Type);
+ Asm->OutStreamer->AddComment(dwarf::FormEncodingString(A.Form));
+ Asm->EmitInt16(A.Form);
+ }
+}
+
+void AppleAccelTableHeader::setBucketAndHashCount(uint32_t HashCount) {
+ if (HashCount > 1024)
+ Header.BucketCount = HashCount / 4;
+ else if (HashCount > 16)
+ Header.BucketCount = HashCount / 2;
+ else
+ Header.BucketCount = HashCount > 0 ? HashCount : 1;
+
+ Header.HashCount = HashCount;
+}
+
+constexpr AppleAccelTableHeader::Atom AppleAccelTableTypeData::Atoms[];
+constexpr AppleAccelTableHeader::Atom AppleAccelTableOffsetData::Atoms[];
+
+void AppleAccelTableBase::emitHeader(AsmPrinter *Asm) { Header.emit(Asm); }
+
+void AppleAccelTableBase::emitBuckets(AsmPrinter *Asm) {
+ unsigned index = 0;
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ Asm->OutStreamer->AddComment("Bucket " + Twine(i));
+ if (!Buckets[i].empty())
+ Asm->EmitInt32(index);
+ else
+ Asm->EmitInt32(std::numeric_limits<uint32_t>::max());
+ // Buckets point in the list of hashes, not to the data. Do not increment
+ // the index multiple times in case of hash collisions.
+ uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
+ for (auto *HD : Buckets[i]) {
+ uint32_t HashValue = HD->HashValue;
+ if (PrevHash != HashValue)
+ ++index;
+ PrevHash = HashValue;
+ }
+ }
+}
+
+void AppleAccelTableBase::emitHashes(AsmPrinter *Asm) {
+ uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
+ unsigned BucketIdx = 0;
+ for (auto &Bucket : Buckets) {
+ for (auto &Hash : Bucket) {
+ uint32_t HashValue = Hash->HashValue;
+ if (PrevHash == HashValue)
+ continue;
+ Asm->OutStreamer->AddComment("Hash in Bucket " + Twine(BucketIdx));
+ Asm->EmitInt32(HashValue);
+ PrevHash = HashValue;
+ }
+ BucketIdx++;
+ }
+}
+
+void AppleAccelTableBase::emitOffsets(AsmPrinter *Asm,
+ const MCSymbol *SecBegin) {
+ uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ for (auto HI = Buckets[i].begin(), HE = Buckets[i].end(); HI != HE; ++HI) {
+ uint32_t HashValue = (*HI)->HashValue;
+ if (PrevHash == HashValue)
+ continue;
+ PrevHash = HashValue;
+ Asm->OutStreamer->AddComment("Offset in Bucket " + Twine(i));
+ MCContext &Context = Asm->OutStreamer->getContext();
+ const MCExpr *Sub = MCBinaryExpr::createSub(
+ MCSymbolRefExpr::create((*HI)->Sym, Context),
+ MCSymbolRefExpr::create(SecBegin, Context), Context);
+ Asm->OutStreamer->EmitValue(Sub, sizeof(uint32_t));
+ }
+ }
+}
+
+void AppleAccelTableBase::emitData(AsmPrinter *Asm) {
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
+ for (auto &Hash : Buckets[i]) {
+ // Terminate the previous entry if there is no hash collision with the
+ // current one.
+ if (PrevHash != std::numeric_limits<uint64_t>::max() &&
+ PrevHash != Hash->HashValue)
+ Asm->EmitInt32(0);
+ // Remember to emit the label for our offset.
+ Asm->OutStreamer->EmitLabel(Hash->Sym);
+ Asm->OutStreamer->AddComment(Hash->Str);
+ Asm->emitDwarfStringOffset(Hash->Data.Name);
+ Asm->OutStreamer->AddComment("Num DIEs");
+ Asm->EmitInt32(Hash->Data.Values.size());
+ for (const auto *V : Hash->Data.Values) {
+ V->emit(Asm);
+ }
+ PrevHash = Hash->HashValue;
+ }
+ // Emit the final end marker for the bucket.
+ if (!Buckets[i].empty())
+ Asm->EmitInt32(0);
+ }
+}
+
+void AppleAccelTableBase::computeBucketCount() {
+ // First get the number of unique hashes.
+ std::vector<uint32_t> uniques(Data.size());
+ for (size_t i = 0, e = Data.size(); i < e; ++i)
+ uniques[i] = Data[i]->HashValue;
+ array_pod_sort(uniques.begin(), uniques.end());
+ std::vector<uint32_t>::iterator p =
+ std::unique(uniques.begin(), uniques.end());
+
+ // Compute the hashes count and use it to set that together with the bucket
+ // count in the header.
+ Header.setBucketAndHashCount(std::distance(uniques.begin(), p));
+}
+
+void AppleAccelTableBase::finalizeTable(AsmPrinter *Asm, StringRef Prefix) {
+ // Create the individual hash data outputs.
+ Data.reserve(Entries.size());
+ for (auto &E : Entries) {
+ // Unique the entries.
+ std::stable_sort(E.second.Values.begin(), E.second.Values.end(),
+ [](const AppleAccelTableData *A,
+ const AppleAccelTableData *B) { return *A < *B; });
+ E.second.Values.erase(
+ std::unique(E.second.Values.begin(), E.second.Values.end()),
+ E.second.Values.end());
+
+ HashData *Entry = new (Allocator) HashData(E.first(), E.second);
+ Data.push_back(Entry);
+ }
+
+ // Figure out how many buckets we need, then compute the bucket contents and
+ // the final ordering. We'll emit the hashes and offsets by doing a walk
+ // during the emission phase. We add temporary symbols to the data so that we
+ // can reference them during the offset later, we'll emit them when we emit
+ // the data.
+ computeBucketCount();
+
+ // Compute bucket contents and final ordering.
+ Buckets.resize(Header.getBucketCount());
+ for (auto &D : Data) {
+ uint32_t bucket = D->HashValue % Header.getBucketCount();
+ Buckets[bucket].push_back(D);
+ D->Sym = Asm->createTempSymbol(Prefix);
+ }
+
+ // Sort the contents of the buckets by hash value so that hash collisions end
+ // up together. Stable sort makes testing easier and doesn't cost much more.
+ for (auto &Bucket : Buckets)
+ std::stable_sort(Bucket.begin(), Bucket.end(),
+ [](HashData *LHS, HashData *RHS) {
+ return LHS->HashValue < RHS->HashValue;
+ });
+}
+
+void AppleAccelTableOffsetData::emit(AsmPrinter *Asm) const {
+ Asm->EmitInt32(Die->getDebugSectionOffset());
+}
+
+void AppleAccelTableTypeData::emit(AsmPrinter *Asm) const {
+ Asm->EmitInt32(Die->getDebugSectionOffset());
+ Asm->EmitInt16(Die->getTag());
+ Asm->EmitInt8(0);
+}
generated by cgit v1.1 at 2025-10-07 20:43:23 +0000