AsmParser/Bitcode: Add support for MDLocation

This adds assembly and bitcode support for `MDLocation`.  The assembly
side is rather big, since this is the first `MDNode` subclass (that
isn't `MDTuple`).  Part of PR21433.

(If you're wondering where the mountains of testcase updates are, we
don't need them until I update `DILocation` and `DebugLoc` to actually
use this class.)

llvm-svn: 225830

3 files changed, 44 insertions, 1 deletions

diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 9d14a1afb61..a96e866ed2c 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -779,6 +779,25 @@ static void WriteMDNode(const MDNode *N,
   Record.clear();
 }
 
+static void WriteMDLocation(const MDLocation *N, const ValueEnumerator &VE,
+                            BitstreamWriter &Stream,
+                            SmallVectorImpl<uint64_t> &Record,
+                            unsigned Abbrev) {
+  Record.push_back(N->isDistinct());
+  Record.push_back(N->getLine());
+  Record.push_back(N->getColumn());
+  Record.push_back(VE.getMetadataID(N->getScope()));
+
+  // Always emit the inlined-at location, even though it's optional.
+  if (Metadata *InlinedAt = N->getInlinedAt())
+    Record.push_back(VE.getMetadataID(InlinedAt) + 1);
+  else
+    Record.push_back(0);
+
+  Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
+  Record.clear();
+}
+
 static void WriteModuleMetadata(const Module *M,
                                 const ValueEnumerator &VE,
                                 BitstreamWriter &Stream) {
@@ -798,6 +817,22 @@ static void WriteModuleMetadata(const Module *M,
     MDSAbbrev = Stream.EmitAbbrev(Abbv);
   }
 
+  unsigned LocAbbrev = 0;
+  if (VE.hasMDLocation()) {
+    // Abbrev for METADATA_LOCATION.
+    //
+    // Assume the column is usually under 128, and always output the inlined-at
+    // location (it's never more expensive than building an array size 1).
+    BitCodeAbbrev *Abbv = new BitCodeAbbrev();
+    Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+    Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
+    LocAbbrev = Stream.EmitAbbrev(Abbv);
+  }
+
   unsigned NameAbbrev = 0;
   if (!M->named_metadata_empty()) {
     // Abbrev for METADATA_NAME.
@@ -810,6 +845,10 @@ static void WriteModuleMetadata(const Module *M,
 
   SmallVector<uint64_t, 64> Record;
   for (const Metadata *MD : MDs) {
+    if (const MDLocation *Loc = dyn_cast<MDLocation>(MD)) {
+      WriteMDLocation(Loc, VE, Stream, Record, LocAbbrev);
+      continue;
+    }
     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
       WriteMDNode(N, VE, Stream, Record);
       continue;
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index b117d7bb49a..27a63d8fefc 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -282,7 +282,8 @@ static bool isIntOrIntVectorValue(const std::pair<const Value*, unsigned> &V) {
   return V.first->getType()->isIntOrIntVectorTy();
 }
 
-ValueEnumerator::ValueEnumerator(const Module &M) : HasMDString(false) {
+ValueEnumerator::ValueEnumerator(const Module &M)
+    : HasMDString(false), HasMDLocation(false) {
   if (shouldPreserveBitcodeUseListOrder())
     UseListOrders = predictUseListOrder(M);
 
@@ -547,6 +548,7 @@ void ValueEnumerator::EnumerateMetadata(const Metadata *MD) {
     EnumerateValue(C->getValue());
 
   HasMDString |= isa<MDString>(MD);
+  HasMDLocation |= isa<MDLocation>(MD);
 
   // Replace the dummy ID inserted above with the correct one.  MDValueMap may
   // have changed by inserting operands, so we need a fresh lookup here.
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.h b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
index e63394fefa5..d363c1be0dd 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
@@ -65,6 +65,7 @@ private:
   typedef DenseMap<const Metadata *, unsigned> MetadataMapType;
   MetadataMapType MDValueMap;
   bool HasMDString;
+  bool HasMDLocation;
 
   typedef DenseMap<AttributeSet, unsigned> AttributeGroupMapType;
   AttributeGroupMapType AttributeGroupMap;
@@ -111,6 +112,7 @@ public:
   unsigned getMetadataID(const Metadata *V) const;
 
   bool hasMDString() const { return HasMDString; }
+  bool hasMDLocation() const { return HasMDLocation; }
 
   unsigned getTypeID(Type *T) const {
     TypeMapType::const_iterator I = TypeMap.find(T);