[DWARF] Improved error reporting for range lists.

Errors found processing the DW_AT_ranges attribute are propagated by lower level 
routines and reported by their callers.

Reviewer: JDevlieghere

Differential Revision: https://reviews.llvm.org/D48344



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335188 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 108 insertions, 51 deletions

diff --git a/lib/DebugInfo/DWARF/DWARFContext.cpp b/lib/DebugInfo/DWARF/DWARFContext.cpp
index a4053a30536..2ac94d05bc6 100644
--- a/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -470,8 +470,13 @@ void DWARFContext::dump(
                                   isLittleEndian(), savedAddressByteSize);
     uint32_t offset = 0;
     DWARFDebugRangeList rangeList;
-    while (rangeList.extract(rangesData, &offset))
+    while (rangesData.isValidOffset(offset)) {
+      if (Error E = rangeList.extract(rangesData, &offset)) {
+        WithColor::error() << toString(std::move(E)) << '\n';
+        break;  
+      }
       rangeList.dump(OS);
+    }
   }
 
   if (shouldDump(Explicit, ".debug_rnglists", DIDT_ID_DebugRnglists,
diff --git a/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp b/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
index 87a0fd366af..a565718debd 100644
--- a/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
@@ -16,20 +16,30 @@
 
 using namespace llvm;
 
+// FIXME: There are several versions of this. Consolidate them.
+template <typename... Ts>
+static Error createError(char const *Fmt, const Ts &... Vals) {
+  std::string Buffer;
+  raw_string_ostream Stream(Buffer);
+  Stream << format(Fmt, Vals...);
+  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
+}
+
 void DWARFDebugRangeList::clear() {
   Offset = -1U;
   AddressSize = 0;
   Entries.clear();
 }
 
-bool DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
-                                  uint32_t *offset_ptr) {
+Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
+                                   uint32_t *offset_ptr) {
   clear();
   if (!data.isValidOffset(*offset_ptr))
-    return false;
+    return createError("invalid range list offset 0x%" PRIx32, *offset_ptr);
+
   AddressSize = data.getAddressSize();
   if (AddressSize != 4 && AddressSize != 8)
-    return false;
+    return createError("invalid address size: %d", AddressSize);
   Offset = *offset_ptr;
   while (true) {
     RangeListEntry Entry;
@@ -43,13 +53,14 @@ bool DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
     // Check that both values were extracted correctly.
     if (*offset_ptr != prev_offset + 2 * AddressSize) {
       clear();
-      return false;
+      return createError("invalid range list entry at offset 0x%" PRIx32,
+                         prev_offset);
     }
     if (Entry.isEndOfListEntry())
       break;
     Entries.push_back(Entry);
   }
-  return true;
+  return Error::success();
 }
 
 void DWARFDebugRangeList::dump(raw_ostream &OS) const {
diff --git a/lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp b/lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp
index 34359c0ef87..533b0922c1d 100644
--- a/lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDebugRnglists.cpp
@@ -208,6 +208,8 @@ DWARFAddressRangesVector DWARFDebugRnglist::getAbsoluteRanges(
 
 Error DWARFDebugRnglist::extract(DWARFDataExtractor Data, uint32_t HeaderOffset,
                                  uint32_t End, uint32_t *OffsetPtr) {
+  if (*OffsetPtr < HeaderOffset || *OffsetPtr >= End)
+    return createError("invalid range list offset 0x%" PRIx32, *OffsetPtr);
   Entries.clear();
   while (*OffsetPtr < End) {
     RangeListEntry Entry{0, 0, 0, 0, 0};
@@ -351,7 +353,7 @@ uint32_t DWARFDebugRnglistTable::length() const {
   return HeaderData.Length + sizeof(uint32_t);
 }
 
-Optional<DWARFDebugRnglist>
+Expected<DWARFDebugRnglist>
 DWARFDebugRnglistTable::findRangeList(DWARFDataExtractor Data,
                                       uint32_t Offset) {
   auto Entry = Ranges.find(Offset);
@@ -362,10 +364,8 @@ DWARFDebugRnglistTable::findRangeList(DWARFDataExtractor Data,
   DWARFDebugRnglist RngList;
   uint32_t End = HeaderOffset + length();
   uint32_t StartingOffset = Offset;
-  if (Error E = RngList.extract(Data, HeaderOffset, End, &Offset)) {
-    llvm::consumeError(std::move(E));
-    return None;
-  }
+  if (Error E = RngList.extract(Data, HeaderOffset, End, &Offset))
+    return std::move(E);
   Ranges[StartingOffset] = RngList;
   return RngList;
 }
diff --git a/lib/DebugInfo/DWARF/DWARFDie.cpp b/lib/DebugInfo/DWARF/DWARFDie.cpp
index a471d97d75d..0ef65c2b0b6 100644
--- a/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -270,8 +270,12 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
         FV.setUValue(*RangeListOffset);
         FV.dump(OS, DumpOpts);
       }
-    dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
-               sizeof(BaseIndent) + Indent + 4, DumpOpts);
+    if (auto RangesOrError = Die.getAddressRanges())
+      dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
+                 sizeof(BaseIndent) + Indent + 4, DumpOpts);
+    else
+      WithColor::error() << "decoding address ranges: "
+                         << toString(RangesOrError.takeError()) << '\n';
   }
 
   OS << ")\n";
@@ -385,13 +389,13 @@ bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
   return false;
 }
 
-DWARFAddressRangesVector DWARFDie::getAddressRanges() const {
+Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
   if (isNULL())
     return DWARFAddressRangesVector();
   // Single range specified by low/high PC.
   uint64_t LowPC, HighPC, Index;
   if (getLowAndHighPC(LowPC, HighPC, Index))
-    return {{LowPC, HighPC, Index}};
+    return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
 
   Optional<DWARFFormValue> Value = find(DW_AT_ranges);
   if (Value) {
@@ -407,8 +411,11 @@ void DWARFDie::collectChildrenAddressRanges(
   if (isNULL())
     return;
   if (isSubprogramDIE()) {
-    const auto &DIERanges = getAddressRanges();
-    Ranges.insert(Ranges.end(), DIERanges.begin(), DIERanges.end());
+    if (auto DIERangesOrError = getAddressRanges())
+      Ranges.insert(Ranges.end(), DIERangesOrError.get().begin(),
+                    DIERangesOrError.get().end());
+    else
+      llvm::consumeError(DIERangesOrError.takeError());
   }
 
   for (auto Child : children())
@@ -416,10 +423,15 @@ void DWARFDie::collectChildrenAddressRanges(
 }
 
 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
-  for (const auto &R : getAddressRanges()) {
+  auto RangesOrError = getAddressRanges();
+  if (!RangesOrError) {
+    llvm::consumeError(RangesOrError.takeError());
+    return false;
+  }
+
+  for (const auto &R : RangesOrError.get())
     if (R.LowPC <= Address && Address < R.HighPC)
       return true;
-  }
   return false;
 }
 
diff --git a/lib/DebugInfo/DWARF/DWARFUnit.cpp b/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 260c5dc94c4..6b7970d426b 100644
--- a/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -181,8 +181,8 @@ parseRngListTableHeader(DWARFDataExtractor &DA, uint32_t Offset) {
   return Table;
 }
 
-bool DWARFUnit::extractRangeList(uint32_t RangeListOffset,
-                                 DWARFDebugRangeList &RangeList) const {
+Error DWARFUnit::extractRangeList(uint32_t RangeListOffset,
+                                  DWARFDebugRangeList &RangeList) const {
   // Require that compile unit is extracted.
   assert(!DieArray.empty());
   DWARFDataExtractor RangesData(Context.getDWARFObj(), *RangeSection,
@@ -397,26 +397,39 @@ void DWARFUnit::clearDIEs(bool KeepCUDie) {
   }
 }
 
-DWARFAddressRangesVector DWARFUnit::findRnglistFromOffset(uint32_t Offset) {
+Expected<DWARFAddressRangesVector>
+DWARFUnit::findRnglistFromOffset(uint32_t Offset) {
   if (getVersion() <= 4) {
     DWARFDebugRangeList RangeList;
-    if (extractRangeList(Offset, RangeList))
-      return RangeList.getAbsoluteRanges(getBaseAddress());
-    return DWARFAddressRangesVector();
+    if (Error E = extractRangeList(Offset, RangeList))
+      return std::move(E);
+    return RangeList.getAbsoluteRanges(getBaseAddress());
   }
   if (RngListTable) {
     DWARFDataExtractor RangesData(Context.getDWARFObj(), *RangeSection,
                                   isLittleEndian, RngListTable->getAddrSize());
-    if (auto RangeList = RngListTable->findRangeList(RangesData, Offset))
-      return RangeList->getAbsoluteRanges(getBaseAddress());
+    auto RangeListOrError = RngListTable->findRangeList(RangesData, Offset);
+    if (RangeListOrError)
+      return RangeListOrError.get().getAbsoluteRanges(getBaseAddress());
+    return RangeListOrError.takeError();
   }
-  return DWARFAddressRangesVector();
+
+  return make_error<StringError>("missing or invalid range list table",
+                                 inconvertibleErrorCode());
 }
 
-DWARFAddressRangesVector DWARFUnit::findRnglistFromIndex(uint32_t Index) {
+Expected<DWARFAddressRangesVector>
+DWARFUnit::findRnglistFromIndex(uint32_t Index) {
   if (auto Offset = getRnglistOffset(Index))
     return findRnglistFromOffset(*Offset + RangeSectionBase);
-  return DWARFAddressRangesVector();
+
+  std::string Buffer;
+  raw_string_ostream Stream(Buffer);
+  if (RngListTable)
+    Stream << format("invalid range list table index %d", Index);
+  else
+    Stream << "missing or invalid range list table";
+  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
 }
 
 void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
@@ -424,11 +437,16 @@ void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
   if (!UnitDie)
     return;
   // First, check if unit DIE describes address ranges for the whole unit.
-  const auto &CUDIERanges = UnitDie.getAddressRanges();
-  if (!CUDIERanges.empty()) {
-    CURanges.insert(CURanges.end(), CUDIERanges.begin(), CUDIERanges.end());
-    return;
-  }
+  auto CUDIERangesOrError = UnitDie.getAddressRanges();
+  if (CUDIERangesOrError) {
+    if (!CUDIERangesOrError.get().empty()) {
+      CURanges.insert(CURanges.end(), CUDIERangesOrError.get().begin(),
+                      CUDIERangesOrError.get().end());
+      return;
+    }
+  } else
+    WithColor::error() << "decoding address ranges: "
+                       << toString(CUDIERangesOrError.takeError()) << '\n';
 
   // This function is usually called if there in no .debug_aranges section
   // in order to produce a compile unit level set of address ranges that
@@ -454,21 +472,25 @@ void DWARFUnit::collectAddressRanges(DWARFAddressRangesVector &CURanges) {
 
 void DWARFUnit::updateAddressDieMap(DWARFDie Die) {
   if (Die.isSubroutineDIE()) {
-    for (const auto &R : Die.getAddressRanges()) {
-      // Ignore 0-sized ranges.
-      if (R.LowPC == R.HighPC)
-        continue;
-      auto B = AddrDieMap.upper_bound(R.LowPC);
-      if (B != AddrDieMap.begin() && R.LowPC < (--B)->second.first) {
-        // The range is a sub-range of existing ranges, we need to split the
-        // existing range.
-        if (R.HighPC < B->second.first)
-          AddrDieMap[R.HighPC] = B->second;
-        if (R.LowPC > B->first)
-          AddrDieMap[B->first].first = R.LowPC;
+    auto DIERangesOrError = Die.getAddressRanges();
+    if (DIERangesOrError) {
+      for (const auto &R : DIERangesOrError.get()) {
+        // Ignore 0-sized ranges.
+        if (R.LowPC == R.HighPC)
+          continue;
+        auto B = AddrDieMap.upper_bound(R.LowPC);
+        if (B != AddrDieMap.begin() && R.LowPC < (--B)->second.first) {
+          // The range is a sub-range of existing ranges, we need to split the
+          // existing range.
+          if (R.HighPC < B->second.first)
+            AddrDieMap[R.HighPC] = B->second;
+          if (R.LowPC > B->first)
+            AddrDieMap[B->first].first = R.LowPC;
+        }
+        AddrDieMap[R.LowPC] = std::make_pair(R.HighPC, Die);
       }
-      AddrDieMap[R.LowPC] = std::make_pair(R.HighPC, Die);
-    }
+    } else
+      llvm::consumeError(DIERangesOrError.takeError());
   }
   // Parent DIEs are added to the AddrDieMap prior to the Children DIEs to
   // simplify the logic to update AddrDieMap. The child's range will always
diff --git a/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index e456de5b103..bb52f062d28 100644
--- a/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -324,8 +324,15 @@ unsigned DWARFVerifier::verifyDieRanges(const DWARFDie &Die,
   if (!Die.isValid())
     return NumErrors;
 
-  DWARFAddressRangesVector Ranges = Die.getAddressRanges();
+  auto RangesOrError = Die.getAddressRanges();
+  if (!RangesOrError) {
+    // FIXME: Report the error.
+    ++NumErrors;
+    llvm::consumeError(RangesOrError.takeError());
+    return NumErrors;
+  }
 
+  DWARFAddressRangesVector Ranges = RangesOrError.get();
   // Build RI for this DIE and check that ranges within this DIE do not
   // overlap.
   DieRangeInfo RI(Die);