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-rw-r--r--lib/CodeGen/AsmPrinter/DwarfAccelTable.cpp287
1 files changed, 287 insertions, 0 deletions
diff --git a/lib/CodeGen/AsmPrinter/DwarfAccelTable.cpp b/lib/CodeGen/AsmPrinter/DwarfAccelTable.cpp
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+++ b/lib/CodeGen/AsmPrinter/DwarfAccelTable.cpp
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+//=-- llvm/CodeGen/DwarfAccelTable.cpp - Dwarf Accelerator Tables -*- C++ -*-=//
+//
+// 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 dwarf accelerator tables.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DwarfAccelTable.h"
+#include "DwarfDebug.h"
+#include "DIE.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/Debug.h"
+
+using namespace llvm;
+
+const char *DwarfAccelTable::Atom::AtomTypeString(enum AtomType AT) {
+ switch (AT) {
+ case eAtomTypeNULL: return "eAtomTypeNULL";
+ case eAtomTypeDIEOffset: return "eAtomTypeDIEOffset";
+ case eAtomTypeCUOffset: return "eAtomTypeCUOffset";
+ case eAtomTypeTag: return "eAtomTypeTag";
+ case eAtomTypeNameFlags: return "eAtomTypeNameFlags";
+ case eAtomTypeTypeFlags: return "eAtomTypeTypeFlags";
+ }
+ llvm_unreachable("invalid AtomType!");
+}
+
+// The general case would need to have a less hard coded size for the
+// length of the HeaderData, however, if we're constructing based on a
+// single Atom then we know it will always be: 4 + 4 + 2 + 2.
+DwarfAccelTable::DwarfAccelTable(DwarfAccelTable::Atom atom) :
+ Header(12),
+ HeaderData(atom) {
+}
+
+// The length of the header data is always going to be 4 + 4 + 4*NumAtoms.
+DwarfAccelTable::DwarfAccelTable(std::vector<DwarfAccelTable::Atom> &atomList) :
+ Header(8 + (atomList.size() * 4)),
+ HeaderData(atomList) {
+}
+
+DwarfAccelTable::~DwarfAccelTable() {
+ for (size_t i = 0, e = Data.size(); i < e; ++i)
+ delete Data[i];
+ for (StringMap<DataArray>::iterator
+ EI = Entries.begin(), EE = Entries.end(); EI != EE; ++EI)
+ for (DataArray::iterator DI = EI->second.begin(),
+ DE = EI->second.end(); DI != DE; ++DI)
+ delete (*DI);
+}
+
+void DwarfAccelTable::AddName(StringRef Name, DIE* die, char Flags) {
+ // If the string is in the list already then add this die to the list
+ // otherwise add a new one.
+ DataArray &DIEs = Entries[Name];
+ DIEs.push_back(new HashDataContents(die, Flags));
+}
+
+void DwarfAccelTable::ComputeBucketCount(void) {
+ // 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());
+ uint32_t num = std::distance(uniques.begin(), p);
+
+ // Then compute the bucket size, minimum of 1 bucket.
+ if (num > 1024) Header.bucket_count = num/4;
+ if (num > 16) Header.bucket_count = num/2;
+ else Header.bucket_count = num > 0 ? num : 1;
+
+ Header.hashes_count = num;
+}
+
+namespace {
+ // DIESorter - comparison predicate that sorts DIEs by their offset.
+ struct DIESorter {
+ bool operator()(const struct DwarfAccelTable::HashDataContents *A,
+ const struct DwarfAccelTable::HashDataContents *B) const {
+ return A->Die->getOffset() < B->Die->getOffset();
+ }
+ };
+}
+
+void DwarfAccelTable::FinalizeTable(AsmPrinter *Asm, const char *Prefix) {
+ // Create the individual hash data outputs.
+ for (StringMap<DataArray>::iterator
+ EI = Entries.begin(), EE = Entries.end(); EI != EE; ++EI) {
+ struct HashData *Entry = new HashData((*EI).getKeyData());
+
+ // Unique the entries.
+ std::stable_sort(EI->second.begin(), EI->second.end(), DIESorter());
+ EI->second.erase(std::unique(EI->second.begin(), EI->second.end()),
+ EI->second.end());
+
+ for (DataArray::const_iterator DI = EI->second.begin(),
+ DE = EI->second.end();
+ DI != DE; ++DI)
+ Entry->addData((*DI));
+ 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.bucket_count);
+ for (size_t i = 0, e = Data.size(); i < e; ++i) {
+ uint32_t bucket = Data[i]->HashValue % Header.bucket_count;
+ Buckets[bucket].push_back(Data[i]);
+ Data[i]->Sym = Asm->GetTempSymbol(Prefix, i);
+ }
+}
+
+// Emits the header for the table via the AsmPrinter.
+void DwarfAccelTable::EmitHeader(AsmPrinter *Asm) {
+ 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.hash_function);
+ Asm->OutStreamer.AddComment("Header Bucket Count");
+ Asm->EmitInt32(Header.bucket_count);
+ Asm->OutStreamer.AddComment("Header Hash Count");
+ Asm->EmitInt32(Header.hashes_count);
+ Asm->OutStreamer.AddComment("Header Data Length");
+ Asm->EmitInt32(Header.header_data_len);
+ Asm->OutStreamer.AddComment("HeaderData Die Offset Base");
+ Asm->EmitInt32(HeaderData.die_offset_base);
+ 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(Atom::AtomTypeString(A.type));
+ Asm->EmitInt16(A.type);
+ Asm->OutStreamer.AddComment(dwarf::FormEncodingString(A.form));
+ Asm->EmitInt16(A.form);
+ }
+}
+
+// Walk through and emit the buckets for the table. This will look
+// like a list of numbers of how many elements are in each bucket.
+void DwarfAccelTable::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].size() != 0)
+ Asm->EmitInt32(index);
+ else
+ Asm->EmitInt32(UINT32_MAX);
+ index += Buckets[i].size();
+ }
+}
+
+// Walk through the buckets and emit the individual hashes for each
+// bucket.
+void DwarfAccelTable::EmitHashes(AsmPrinter *Asm) {
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ for (HashList::const_iterator HI = Buckets[i].begin(),
+ HE = Buckets[i].end(); HI != HE; ++HI) {
+ Asm->OutStreamer.AddComment("Hash in Bucket " + Twine(i));
+ Asm->EmitInt32((*HI)->HashValue);
+ }
+ }
+}
+
+// Walk through the buckets and emit the individual offsets for each
+// element in each bucket. This is done via a symbol subtraction from the
+// beginning of the section. The non-section symbol will be output later
+// when we emit the actual data.
+void DwarfAccelTable::EmitOffsets(AsmPrinter *Asm, MCSymbol *SecBegin) {
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ for (HashList::const_iterator HI = Buckets[i].begin(),
+ HE = Buckets[i].end(); HI != HE; ++HI) {
+ 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), 0);
+ }
+ }
+}
+
+// Walk through the buckets and emit the full data for each element in
+// the bucket. For the string case emit the dies and the various offsets.
+// Terminate each HashData bucket with 0.
+void DwarfAccelTable::EmitData(AsmPrinter *Asm, DwarfDebug *D) {
+ uint64_t PrevHash = UINT64_MAX;
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
+ for (HashList::const_iterator HI = Buckets[i].begin(),
+ HE = Buckets[i].end(); HI != HE; ++HI) {
+ // Remember to emit the label for our offset.
+ Asm->OutStreamer.EmitLabel((*HI)->Sym);
+ Asm->OutStreamer.AddComment((*HI)->Str);
+ Asm->EmitSectionOffset(D->getStringPoolEntry((*HI)->Str),
+ D->getStringPool());
+ Asm->OutStreamer.AddComment("Num DIEs");
+ Asm->EmitInt32((*HI)->Data.size());
+ for (std::vector<struct HashDataContents*>::const_iterator
+ DI = (*HI)->Data.begin(), DE = (*HI)->Data.end();
+ DI != DE; ++DI) {
+ // Emit the DIE offset
+ Asm->EmitInt32((*DI)->Die->getOffset());
+ // If we have multiple Atoms emit that info too.
+ // FIXME: A bit of a hack, we either emit only one atom or all info.
+ if (HeaderData.Atoms.size() > 1) {
+ Asm->EmitInt16((*DI)->Die->getTag());
+ Asm->EmitInt8((*DI)->Flags);
+ }
+ }
+ // Emit a 0 to terminate the data unless we have a hash collision.
+ if (PrevHash != (*HI)->HashValue)
+ Asm->EmitInt32(0);
+ PrevHash = (*HI)->HashValue;
+ }
+ }
+}
+
+// Emit the entire data structure to the output file.
+void DwarfAccelTable::Emit(AsmPrinter *Asm, MCSymbol *SecBegin,
+ DwarfDebug *D) {
+ // Emit the header.
+ EmitHeader(Asm);
+
+ // Emit the buckets.
+ EmitBuckets(Asm);
+
+ // Emit the hashes.
+ EmitHashes(Asm);
+
+ // Emit the offsets.
+ EmitOffsets(Asm, SecBegin);
+
+ // Emit the hash data.
+ EmitData(Asm, D);
+}
+
+#ifndef NDEBUG
+void DwarfAccelTable::print(raw_ostream &O) {
+
+ Header.print(O);
+ HeaderData.print(O);
+
+ O << "Entries: \n";
+ for (StringMap<DataArray>::const_iterator
+ EI = Entries.begin(), EE = Entries.end(); EI != EE; ++EI) {
+ O << "Name: " << EI->getKeyData() << "\n";
+ for (DataArray::const_iterator DI = EI->second.begin(),
+ DE = EI->second.end();
+ DI != DE; ++DI)
+ (*DI)->print(O);
+ }
+
+ O << "Buckets and Hashes: \n";
+ for (size_t i = 0, e = Buckets.size(); i < e; ++i)
+ for (HashList::const_iterator HI = Buckets[i].begin(),
+ HE = Buckets[i].end(); HI != HE; ++HI)
+ (*HI)->print(O);
+
+ O << "Data: \n";
+ for (std::vector<HashData*>::const_iterator
+ DI = Data.begin(), DE = Data.end(); DI != DE; ++DI)
+ (*DI)->print(O);
+
+
+}
+#endif
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