From: Bob Wilson <bob.wilson@apple.com>
Date: Sun, 22 Nov 2009 03:58:57 +0000 (+0000)
Subject: Fix pr5470. Tablegen handles template arguments by temporarily setting their
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=2214dc07649d36e47d11914e1ffc7c56eb40ad73;p=oota-llvm.git

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
index 00000000000..91342ecb966
--- /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 7e84d008e69..fbe120759d3 100644
--- 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;
 }