[CodeView] Hook up CodeViewRecordIO to type serialization path.

Previously support had been added for using CodeViewRecordIO
to read (deserialize) CodeView type records.  This patch adds
support for writing those same records.  With this patch,
reading and writing of CodeView type records finally uses a single
codepath.

Differential Revision: https://reviews.llvm.org/D26253

llvm-svn: 286304

1 files changed, 33 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/CodeViewRecordIO.cpp b/llvm/lib/DebugInfo/CodeView/CodeViewRecordIO.cpp
index 7841e4f2f6a..19facaec9f0 100644
--- a/llvm/lib/DebugInfo/CodeView/CodeViewRecordIO.cpp
+++ b/llvm/lib/DebugInfo/CodeView/CodeViewRecordIO.cpp
@@ -16,20 +16,39 @@
 using namespace llvm;
 using namespace llvm::codeview;
 
-Error CodeViewRecordIO::beginRecord(uint16_t Kind) {
-  assert(!CurrentRecord.hasValue() && "There is already a record active!");
-  CurrentRecord.emplace();
-
-  CurrentRecord->Kind = Kind;
+Error CodeViewRecordIO::beginRecord(Optional<uint32_t> MaxLength) {
+  RecordLimit Limit;
+  Limit.MaxLength = MaxLength;
+  Limit.BeginOffset = getCurrentOffset();
+  Limits.push_back(Limit);
   return Error::success();
 }
 
 Error CodeViewRecordIO::endRecord() {
-  assert(CurrentRecord.hasValue() && "Not in a record!");
-  CurrentRecord.reset();
+  assert(!Limits.empty() && "Not in a record!");
+  Limits.pop_back();
   return Error::success();
 }
 
+uint32_t CodeViewRecordIO::maxFieldLength() const {
+  assert(!Limits.empty() && "Not in a record!");
+
+  // The max length of the next field is the minimum of all lengths that would
+  // be allowed by any of the sub-records we're in.  In practice, we can only
+  // ever be at most 1 sub-record deep (in a FieldList), but this works for
+  // the general case.
+  uint32_t Offset = getCurrentOffset();
+  Optional<uint32_t> Min = Limits.front().bytesRemaining(Offset);
+  for (auto X : makeArrayRef(Limits).drop_front()) {
+    Optional<uint32_t> ThisMin = X.bytesRemaining(Offset);
+    if (ThisMin.hasValue())
+      Min = (Min.hasValue()) ? std::min(*Min, *ThisMin) : *ThisMin;
+  }
+  assert(Min.hasValue() && "Every field must have a maximum length!");
+
+  return *Min;
+}
+
 Error CodeViewRecordIO::skipPadding() {
   assert(!isWriting() && "Cannot skip padding while writing!");
 
@@ -114,7 +133,9 @@ Error CodeViewRecordIO::mapEncodedInteger(APSInt &Value) {
 
 Error CodeViewRecordIO::mapStringZ(StringRef &Value) {
   if (isWriting()) {
-    if (auto EC = Writer->writeZeroString(Value))
+    // Truncate if we attempt to write too much.
+    StringRef S = Value.take_front(maxFieldLength() - 1);
+    if (auto EC = Writer->writeZeroString(S))
       return EC;
   } else {
     if (auto EC = Reader->readZeroString(Value))
@@ -124,6 +145,10 @@ Error CodeViewRecordIO::mapStringZ(StringRef &Value) {
 }
 
 Error CodeViewRecordIO::mapGuid(StringRef &Guid) {
+  constexpr uint32_t GuidSize = 16;
+  if (maxFieldLength() < GuidSize)
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+
   if (isWriting()) {
     assert(Guid.size() == 16 && "Invalid Guid Size!");
     if (auto EC = Writer->writeFixedString(Guid))