Sketch out a DWARF parser.

This introduces a new library to LLVM: libDebugInfo. It will provide debug information
parsing to LLVM. Much of the design and some of the code is taken from the LLDB project.

It also contains an llvm-dwarfdump tool that can dump the abbrevs and DIEs from an
object file. It can be used to write tests for DWARF input and output easily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139627 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 108 insertions, 0 deletions

diff --git a/lib/DebugInfo/DWARFDebugAbbrev.cpp b/lib/DebugInfo/DWARFDebugAbbrev.cpp
new file mode 100644
index 0000000000..68769f05cd
--- /dev/null
+++ b/lib/DebugInfo/DWARFDebugAbbrev.cpp
@@ -0,0 +1,108 @@
+//===-- DWARFDebugAbbrev.cpp ----------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFDebugAbbrev.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+bool DWARFAbbreviationDeclarationSet::extract(DataExtractor data,
+                                              uint32_t* offset_ptr) {
+  const uint32_t beginOffset = *offset_ptr;
+  Offset = beginOffset;
+  clear();
+  DWARFAbbreviationDeclaration abbrevDeclaration;
+  uint32_t prevAbbrAode = 0;
+  while (abbrevDeclaration.extract(data, offset_ptr)) {
+    Decls.push_back(abbrevDeclaration);
+    if (IdxOffset == 0) {
+      IdxOffset = abbrevDeclaration.getCode();
+    } else {
+      if (prevAbbrAode + 1 != abbrevDeclaration.getCode())
+        IdxOffset = UINT32_MAX;// Out of order indexes, we can't do O(1) lookups
+    }
+    prevAbbrAode = abbrevDeclaration.getCode();
+  }
+  return beginOffset != *offset_ptr;
+}
+
+
+void DWARFAbbreviationDeclarationSet::dump(raw_ostream &OS) const {
+  for (unsigned i = 0, e = Decls.size(); i != e; ++i)
+    Decls[i].dump(OS);
+}
+
+
+const DWARFAbbreviationDeclaration*
+DWARFAbbreviationDeclarationSet::getAbbreviationDeclaration(uint32_t abbrCode)
+  const {
+  if (IdxOffset == UINT32_MAX) {
+    DWARFAbbreviationDeclarationCollConstIter pos;
+    DWARFAbbreviationDeclarationCollConstIter end = Decls.end();
+    for (pos = Decls.begin(); pos != end; ++pos) {
+      if (pos->getCode() == abbrCode)
+        return &(*pos);
+    }
+  } else {
+    uint32_t idx = abbrCode - IdxOffset;
+    if (idx < Decls.size())
+      return &Decls[idx];
+  }
+  return NULL;
+}
+
+DWARFDebugAbbrev::DWARFDebugAbbrev() :
+  m_abbrevCollMap(),
+  m_prev_abbr_offset_pos(m_abbrevCollMap.end()) {}
+
+
+void DWARFDebugAbbrev::parse(DataExtractor data) {
+  uint32_t offset = 0;
+
+  while (data.isValidOffset(offset)) {
+    uint32_t initial_cu_offset = offset;
+    DWARFAbbreviationDeclarationSet abbrevDeclSet;
+
+    if (abbrevDeclSet.extract(data, &offset))
+      m_abbrevCollMap[initial_cu_offset] = abbrevDeclSet;
+    else
+      break;
+  }
+  m_prev_abbr_offset_pos = m_abbrevCollMap.end();
+}
+
+void DWARFDebugAbbrev::dump(raw_ostream &OS) const {
+  if (m_abbrevCollMap.empty()) {
+    OS << "< EMPTY >\n";
+    return;
+  }
+
+  DWARFAbbreviationDeclarationCollMapConstIter pos;
+  for (pos = m_abbrevCollMap.begin(); pos != m_abbrevCollMap.end(); ++pos) {
+    OS << format("Abbrev table for offset: 0x%8.8x\n", pos->first);
+    pos->second.dump(OS);
+  }
+}
+
+const DWARFAbbreviationDeclarationSet*
+DWARFDebugAbbrev::getAbbreviationDeclarationSet(uint64_t cu_abbr_offset) const {
+  DWARFAbbreviationDeclarationCollMapConstIter end = m_abbrevCollMap.end();
+  DWARFAbbreviationDeclarationCollMapConstIter pos;
+  if (m_prev_abbr_offset_pos != end &&
+      m_prev_abbr_offset_pos->first == cu_abbr_offset) {
+    return &(m_prev_abbr_offset_pos->second);
+  } else {
+    pos = m_abbrevCollMap.find(cu_abbr_offset);
+    m_prev_abbr_offset_pos = pos;
+  }
+
+  if (pos != m_abbrevCollMap.end())
+    return &(pos->second);
+  return NULL;
+}