From 52086f802e37fbb2acc61c49120990b0b3fd10cd Mon Sep 17 00:00:00 2001
From: River Riddle <riddleriver@gmail.com>
Date: Mon, 10 Feb 2020 17:51:26 -0800
Subject: [PATCH] [llvm][TableGen] Define FieldInit::isConcrete overload

Summary:
There are a few field init values that are concrete but not complete/foldable (e.g. `?`). This allows for using those values as initializers without erroring out.

Example:

```
class A {
  string value = ?;
}
class B<A impl> : A {
  let value = impl.value; // This currently emits an error.
  let value = ?;          // This doesn't emit an error.
}
```

Differential Revision: https://reviews.llvm.org/D74360
---
 llvm/include/llvm/TableGen/Record.h             |  1 +
 llvm/lib/TableGen/Record.cpp                    |  8 ++++++++
 llvm/test/TableGen/field-access-initializers.td | 23 +++++++++++++++++++++++
 3 files changed, 32 insertions(+)
 create mode 100644 llvm/test/TableGen/field-access-initializers.td

diff --git a/llvm/include/llvm/TableGen/Record.h b/llvm/include/llvm/TableGen/Record.h
index 6667afe..48aeaa1 100644
--- a/llvm/include/llvm/TableGen/Record.h
+++ b/llvm/include/llvm/TableGen/Record.h
@@ -1295,6 +1295,7 @@ public:
   Init *resolveReferences(Resolver &R) const override;
   Init *Fold(Record *CurRec) const;
 
+  bool isConcrete() const override;
   std::string getAsString() const override {
     return Rec->getAsString() + "." + FieldName->getValue().str();
   }
diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index 54ff9ae..ca8cd15 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -1778,6 +1778,14 @@ Init *FieldInit::Fold(Record *CurRec) const {
   return const_cast<FieldInit *>(this);
 }
 
+bool FieldInit::isConcrete() const {
+  if (DefInit *DI = dyn_cast<DefInit>(Rec)) {
+    Init *FieldVal = DI->getDef()->getValue(FieldName)->getValue();
+    return FieldVal->isConcrete();
+  }
+  return false;
+}
+
 static void ProfileCondOpInit(FoldingSetNodeID &ID,
                              ArrayRef<Init *> CondRange,
                              ArrayRef<Init *> ValRange,
diff --git a/llvm/test/TableGen/field-access-initializers.td b/llvm/test/TableGen/field-access-initializers.td
new file mode 100644
index 0000000..5a25e29
--- /dev/null
+++ b/llvm/test/TableGen/field-access-initializers.td
@@ -0,0 +1,23 @@
+// RUN: llvm-tblgen %s | FileCheck %s
+// XFAIL: vg_leak
+
+// CHECK: --- Defs ---
+
+// CHECK: def A1 {
+// CHECK:   string value = ?;
+// CHECK: }
+
+// CHECK: def B1 {
+// CHECK:   string value = A1.value;
+// CHECK: }
+
+class A {
+  string value = ?;
+}
+
+class B<A impl> : A {
+  let value = impl.value;
+}
+
+def A1 : A;
+def B1 : B<A1>;
-- 
2.7.4