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[DebugInfo, PDB] Use sparse bitfields for the name map

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The name map might not be densely packed on disk.  Using a sparse map
will save memory in such situations.

llvm-svn: 271811
This commit is contained in:
David Majnemer 2016-06-04 22:47:39 +00:00
parent dad6c47e6b
commit 6972cf3620
1 changed files with 12 additions and 21 deletions
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33
lib/DebugInfo/PDB/Raw/NameMap.cpp
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@ -8,7 +8,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/PDB/Raw/NameMap.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/SparseBitVector.h"
#include "llvm/DebugInfo/CodeView/StreamReader.h"
#include "llvm/DebugInfo/PDB/Raw/RawError.h"
@ -68,16 +68,16 @@ Error NameMap::load(codeview::StreamReader &Stream) {
return make_error<RawError>(raw_error_code::corrupt_file,
"Number of present words is too large");
// Store all the 'present' bits in a vector for later processing.
SmallVector<uint32_t, 1> PresentWords;
SparseBitVector<> Present;
for (uint32_t I = 0; I != NumPresentWords; ++I) {
uint32_t Word;
if (auto EC = Stream.readInteger(Word))
return joinErrors(std::move(EC),
make_error<RawError>(raw_error_code::corrupt_file,
"Expected name map word"));
PresentWords.push_back(Word);
for (unsigned Idx = 0; Idx < 32; ++Idx)
if (Word & (1U << Idx))
Present.set((I * 32) + Idx);
}
// This appears to be a hash table which uses bitfields to determine whether
@ -93,30 +93,21 @@ Error NameMap::load(codeview::StreamReader &Stream) {
return make_error<RawError>(raw_error_code::corrupt_file,
"Number of deleted words is too large");
// Store all the 'deleted' bits in a vector for later processing.
SmallVector<uint32_t, 1> DeletedWords;
SparseBitVector<> Deleted;
for (uint32_t I = 0; I != NumDeletedWords; ++I) {
uint32_t Word;
if (auto EC = Stream.readInteger(Word))
return joinErrors(std::move(EC),
make_error<RawError>(raw_error_code::corrupt_file,
"Expected name map deleted word"));
DeletedWords.push_back(Word);
"Expected name map word"));
for (unsigned Idx = 0; Idx < 32; ++Idx)
if (Word & (1U << Idx))
Deleted.set((I * 32) + Idx);
}
BitVector Present(MaxNumberOfStrings, false);
if (!PresentWords.empty())
Present.setBitsInMask(PresentWords.data(), PresentWords.size());
BitVector Deleted(MaxNumberOfStrings, false);
if (!DeletedWords.empty())
Deleted.setBitsInMask(DeletedWords.data(), DeletedWords.size());
for (uint32_t I = 0; I < MaxNumberOfStrings; ++I) {
if (!Present.test(I))
continue;
for (unsigned I : Present) {
// For all present entries, dump out their mapping.
(void)I;
// This appears to be an offset relative to the start of the strings.
// It tells us where the null-terminated string begins.