[dwarfdump] Add support for -debug-loc=OFFSET

This patch adds support for passing an offset to -debug-loc.

Differential revision: https://reviews.llvm.org/D38237

llvm-svn: 314286

2 files changed, 48 insertions, 6 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 156c65ad92a..8bb47c94d54 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -291,11 +291,11 @@ void DWARFContext::dump(
 
   if (shouldDump(Explicit, ".debug_loc", DIDT_ID_DebugLoc,
                  DObj->getLocSection().Data)) {
-    getDebugLoc()->dump(OS, getRegisterInfo());
+    getDebugLoc()->dump(OS, getRegisterInfo(), DumpOffset);
   }
   if (shouldDump(ExplicitDWO, ".debug_loc.dwo", DIDT_ID_DebugLoc,
                  DObj->getLocDWOSection().Data)) {
-    getDebugLocDWO()->dump(OS, getRegisterInfo());
+    getDebugLocDWO()->dump(OS, getRegisterInfo(), DumpOffset);
   }
 
   if (shouldDump(Explicit, ".debug_frame", DIDT_ID_DebugFrame,
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
index 68bc0e51306..58f88536f31 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLoc.cpp
@@ -50,11 +50,32 @@ void DWARFDebugLoc::LocationList::dump(raw_ostream &OS, bool IsLittleEndian,
   }
 }
 
-void DWARFDebugLoc::dump(raw_ostream &OS, const MCRegisterInfo *MRI) const {
-  for (const LocationList &L : Locations) {
+DWARFDebugLoc::LocationList const *
+DWARFDebugLoc::getLocationListAtOffset(uint64_t Offset) const {
+  auto It = std::lower_bound(
+      Locations.begin(), Locations.end(), Offset,
+      [](const LocationList &L, uint64_t Offset) { return L.Offset < Offset; });
+  if (It != Locations.end() && It->Offset == Offset)
+    return &(*It);
+  return nullptr;
+}
+
+void DWARFDebugLoc::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
+                         Optional<uint64_t> Offset) const {
+  auto DumpLocationList = [&](const LocationList &L) {
     OS << format("0x%8.8x: ", L.Offset);
     L.dump(OS, IsLittleEndian, AddressSize, MRI, 12);
     OS << "\n\n";
+  };
+
+  if (Offset) {
+    if (auto *L = getLocationListAtOffset(*Offset))
+      DumpLocationList(*L);
+    return;
+  }
+
+  for (const LocationList &L : Locations) {
+    DumpLocationList(L);
   }
 }
 
@@ -161,6 +182,16 @@ void DWARFDebugLocDWO::parse(DataExtractor data) {
   }
 }
 
+DWARFDebugLocDWO::LocationList const *
+DWARFDebugLocDWO::getLocationListAtOffset(uint64_t Offset) const {
+  auto It = std::lower_bound(
+      Locations.begin(), Locations.end(), Offset,
+      [](const LocationList &L, uint64_t Offset) { return L.Offset < Offset; });
+  if (It != Locations.end() && It->Offset == Offset)
+    return &(*It);
+  return nullptr;
+}
+
 void DWARFDebugLocDWO::LocationList::dump(raw_ostream &OS, bool IsLittleEndian,
                                           unsigned AddressSize,
                                           const MCRegisterInfo *MRI,
@@ -173,10 +204,21 @@ void DWARFDebugLocDWO::LocationList::dump(raw_ostream &OS, bool IsLittleEndian,
   }
 }
 
-void DWARFDebugLocDWO::dump(raw_ostream &OS, const MCRegisterInfo *MRI) const {
-  for (const LocationList &L : Locations) {
+void DWARFDebugLocDWO::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
+                            Optional<uint64_t> Offset) const {
+  auto DumpLocationList = [&](const LocationList &L) {
     OS << format("0x%8.8x: ", L.Offset);
     L.dump(OS, IsLittleEndian, AddressSize, MRI, /*Indent=*/12);
     OS << "\n\n";
+  };
+
+  if (Offset) {
+    if (auto *L = getLocationListAtOffset(*Offset))
+      DumpLocationList(*L);
+    return;
+  }
+
+  for (const LocationList &L : Locations) {
+    DumpLocationList(L);
   }
 }