From 9607465f43932913a4e5fc9183e8c63951393b6c Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Thu, 22 Jun 2017 22:18:46 +0000
Subject: [PATCH] PR33002: When we instantiate the definition of a static data
 member, we might have attached an initializer to the in-class declaration. If
 so, include the initializer in the update record for the instantiation.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@306065 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaTemplateInstantiateDecl.cpp |  4 ----
 lib/Serialization/ASTReaderDecl.cpp      | 15 ++++++++++--
 lib/Serialization/ASTWriter.cpp          | 11 ++++++++-
 test/Modules/const-var-init-update.cpp   | 30 ++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100644 test/Modules/const-var-init-update.cpp

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 479760222d..578386fc11 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4290,9 +4290,6 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
       InstantiateVariableInitializer(Var, PatternDecl, TemplateArgs);
       PreviousContext.pop();
 
-      // FIXME: Need to inform the ASTConsumer that we instantiated the
-      // initializer?
-
       // This variable may have local implicit instantiations that need to be
       // instantiated within this scope.
       LocalInstantiations.perform();
@@ -4402,7 +4399,6 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
   if (Def->isStaticDataMember() && !Def->isOutOfLine()) {
     // We're instantiating an inline static data member whose definition was
     // provided inside the class.
-    // FIXME: Update record?
     InstantiateVariableInitializer(Var, Def, TemplateArgs);
   } else if (!VarSpec) {
     Var = cast_or_null<VarDecl>(SubstDecl(Def, Var->getDeclContext(),
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index ed103e6292..3cc3a8efae 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -3934,10 +3934,21 @@ void ASTDeclReader::UpdateDecl(Decl *D) {
       break;
     }
 
-    case UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER:
-      cast<VarDecl>(D)->getMemberSpecializationInfo()->setPointOfInstantiation(
+    case UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER: {
+      VarDecl *VD = cast<VarDecl>(D);
+      VD->getMemberSpecializationInfo()->setPointOfInstantiation(
           ReadSourceLocation());
+      uint64_t Val = Record.readInt();
+      if (Val && !VD->getInit()) {
+        VD->setInit(Record.readExpr());
+        if (Val > 1) { // IsInitKnownICE = 1, IsInitNotICE = 2, IsInitICE = 3
+          EvaluatedStmt *Eval = VD->ensureEvaluatedStmt();
+          Eval->CheckedICE = true;
+          Eval->IsICE = Val == 3;
+        }
+      }
       break;
+    }
 
     case UPD_CXX_INSTANTIATED_DEFAULT_ARGUMENT: {
       auto Param = cast<ParmVarDecl>(D);
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index dcacabec12..1c0db14ced 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -5033,9 +5033,18 @@ void ASTWriter::WriteDeclUpdatesBlocks(RecordDataImpl &OffsetsRecord) {
       case UPD_CXX_ADDED_FUNCTION_DEFINITION:
         break;
 
-      case UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER:
+      case UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER: {
+        const VarDecl *VD = cast<VarDecl>(D);
         Record.AddSourceLocation(Update.getLoc());
+        if (VD->getInit()) {
+          Record.push_back(!VD->isInitKnownICE() ? 1
+                                                 : (VD->isInitICE() ? 3 : 2));
+          Record.AddStmt(const_cast<Expr*>(VD->getInit()));
+        } else {
+          Record.push_back(0);
+        }
         break;
+      }
 
       case UPD_CXX_INSTANTIATED_DEFAULT_ARGUMENT:
         Record.AddStmt(const_cast<Expr *>(
diff --git a/test/Modules/const-var-init-update.cpp b/test/Modules/const-var-init-update.cpp
new file mode 100644
index 0000000000..61080eb839
--- /dev/null
+++ b/test/Modules/const-var-init-update.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++1z -fmodules %s -verify
+// expected-no-diagnostics
+
+#pragma clang module build std
+module std { module limits {} module other {} }
+#pragma clang module contents
+#pragma clang module begin std.limits
+template<typename T> struct numeric_limits {
+  static constexpr T __max = 5;
+  static constexpr T max() { return __max; }
+};
+#pragma clang module end
+#pragma clang module begin std.other
+inline void f() { numeric_limits<int> nl; }
+#pragma clang module end
+#pragma clang module endbuild
+
+#pragma clang module build module_b
+module module_b {}
+#pragma clang module contents
+#pragma clang module begin module_b
+#pragma clang module import std.limits
+constexpr int a = numeric_limits<int>::max();
+#pragma clang module end
+#pragma clang module endbuild
+
+#pragma clang module import std.limits
+#pragma clang module import module_b
+constexpr int b = a;
+static_assert(b == 5);
-- 
2.50.1