Fix pr5470. Tablegen handles template arguments by temporarily setting their

values, resolving references to them, and then removing the definitions.
If a template argument is set to an undefined value, we need to resolve
references to that argument to an explicit undefined value.  The current code
leaves the reference to the template argument as it is, which causes an
assertion failure later when the definition of the template argument is
removed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89581 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/TableGen/UnsetBitInit.td b/test/TableGen/UnsetBitInit.td
new file mode 100644 (file)
index 0000000..91342ec
--- /dev/null
+++ b/test/TableGen/UnsetBitInit.td
@@ -0,0 +1,10 @@
+// RUN: tblgen %s
+class x {
+  field bits<32> A;
+}
+
+class y<bits<2> B> : x {
+  let A{21-20} = B;
+}
+
+def z : y<{0,?}>;

diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index 7e84d00..fbe1207 100644 (file)
--- a/utils/TableGen/Record.cpp
+++ b/utils/TableGen/Record.cpp
@@ -490,8 +490,11 @@ Init *ListInit::resolveListElementReference(Record &R, const RecordVal *IRV,
   if (Elt >= getSize())
     return 0;  // Out of range reference.
   Init *E = getElement(Elt);
-  if (!dynamic_cast<UnsetInit*>(E))  // If the element is set
-    return E;                        // Replace the VarListElementInit with it.
+  // If the element is set to some value, or if we are resolving a reference
+  // to a specific variable and that variable is explicitly unset, then
+  // replace the VarListElementInit with it.
+  if (IRV || !dynamic_cast<UnsetInit*>(E))
+    return E;
   return 0;
 }
 
@@ -1116,8 +1119,11 @@ Init *VarInit::resolveBitReference(Record &R, const RecordVal *IRV,
   assert(Bit < BI->getNumBits() && "Bit reference out of range!");
   Init *B = BI->getBit(Bit);
 
-  if (!dynamic_cast<UnsetInit*>(B))  // If the bit is not set...
-    return B;                        // Replace the VarBitInit with it.
+  // If the bit is set to some value, or if we are resolving a reference to a
+  // specific variable and that variable is explicitly unset, then replace the
+  // VarBitInit with it.
+  if (IRV || !dynamic_cast<UnsetInit*>(B))
+    return B;
   return 0;
 }
 
@@ -1138,8 +1144,11 @@ Init *VarInit::resolveListElementReference(Record &R, const RecordVal *IRV,
   if (Elt >= LI->getSize())
     return 0;  // Out of range reference.
   Init *E = LI->getElement(Elt);
-  if (!dynamic_cast<UnsetInit*>(E))  // If the element is set
-    return E;                        // Replace the VarListElementInit with it.
+  // If the element is set to some value, or if we are resolving a reference
+  // to a specific variable and that variable is explicitly unset, then
+  // replace the VarListElementInit with it.
+  if (IRV || !dynamic_cast<UnsetInit*>(E))
+    return E;
   return 0;
 }
 
@@ -1246,8 +1255,11 @@ Init *FieldInit::resolveListElementReference(Record &R, const RecordVal *RV,
       if (Elt >= LI->getSize()) return 0;
       Init *E = LI->getElement(Elt);
 
-      if (!dynamic_cast<UnsetInit*>(E))  // If the bit is set...
-        return E;                  // Replace the VarListElementInit with it.
+      // If the element is set to some value, or if we are resolving a
+      // reference to a specific variable and that variable is explicitly
+      // unset, then replace the VarListElementInit with it.
+      if (RV || !dynamic_cast<UnsetInit*>(E))
+        return E;
     }
   return 0;
 }