This patch extends the libLLVMDebugInfo which contains a minimalistic DWARF parser:

1) DIContext is now able to return function name for a given instruction address (besides file/line info).
2) llvm-dwarfdump accepts flag --functions that prints the function name (if address is specified by --address flag).
3) test case that checks the basic functionality of llvm-dwarfdump added

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159512 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 4 deletions

diff --git a/lib/DebugInfo/DWARFCompileUnit.cpp b/lib/DebugInfo/DWARFCompileUnit.cpp
index 24bf97ff60..2683990e58 100644
--- a/lib/DebugInfo/DWARFCompileUnit.cpp
+++ b/lib/DebugInfo/DWARFCompileUnit.cpp
@@ -82,7 +82,7 @@ void DWARFCompileUnit::clear() {
   Abbrevs = 0;
   AddrSize = 0;
   BaseAddr = 0;
-  DieArray.clear();
+  clearDIEs(false);
 }
 
 void DWARFCompileUnit::dump(raw_ostream &OS) {
@@ -201,7 +201,7 @@ size_t DWARFCompileUnit::extractDIEsIfNeeded(bool cu_die_only) {
 }
 
 void DWARFCompileUnit::clearDIEs(bool keep_compile_unit_die) {
-  if (DieArray.size() > 1) {
+  if (DieArray.size() > (unsigned)keep_compile_unit_die) {
     // std::vectors never get any smaller when resized to a smaller size,
     // or when clear() or erase() are called, the size will report that it
     // is smaller, but the memory allocated remains intact (call capacity()
@@ -227,8 +227,8 @@ DWARFCompileUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
   // all compile units to stay loaded when they weren't needed. So we can end
   // up parsing the DWARF and then throwing them all away to keep memory usage
   // down.
-  const bool clear_dies = extractDIEsIfNeeded(false) > 1;
-
+  const bool clear_dies = extractDIEsIfNeeded(false) > 1 &&
+                          clear_dies_if_already_not_parsed;
   DieArray[0].buildAddressRangeTable(this, debug_aranges);
 
   // Keep memory down by clearing DIEs if this generate function
@@ -236,3 +236,13 @@ DWARFCompileUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
   if (clear_dies)
     clearDIEs(true);
 }
+
+const DWARFDebugInfoEntryMinimal*
+DWARFCompileUnit::getFunctionDIEForAddress(int64_t address) {
+  size_t n = extractDIEsIfNeeded(false);
+  for (size_t i = 0; i != n; i++) {
+    if (DieArray[i].addressRangeContainsAddress(this, address))
+      return &DieArray[i];
+  }
+  return 0;
+}