From b18da9b12211443ac72e1668fde5f18b626a17f7 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Tue, 20 Feb 2018 12:43:02 +0000
Subject: [PATCH] Revert r325375 "[MS] Make constexpr static data members
 implicitly inline"

This broke Clang bootstrap on Windows, PR36453.

> This handles them exactly the same way that we handle const integral
> static data members with inline definitions, which is what MSVC does.
>
> As a follow-up, now that we have a way to mark variables inline in the
> AST, we should consider marking them implicitly inline there instead of
> only treating them as inline in CodeGen. Unfortunately, this breaks a
> lot of dllimport test cases, so that is future work for now.
>
> Fixes PR36125.

llvm-svn: 325576
---
 clang/lib/AST/ASTContext.cpp                 |  2 +-
 clang/test/CodeGenCXX/static-data-member.cpp | 40 +++-------------------------
 2 files changed, 5 insertions(+), 37 deletions(-)

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 466a5d5..fff714c 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -5857,7 +5857,7 @@ CharUnits ASTContext::getObjCEncodingTypeSize(QualType type) const {
 bool ASTContext::isMSStaticDataMemberInlineDefinition(const VarDecl *VD) const {
   return getTargetInfo().getCXXABI().isMicrosoft() &&
          VD->isStaticDataMember() &&
-         (VD->getType()->isIntegralOrEnumerationType() || VD->isConstexpr()) &&
+         VD->getType()->isIntegralOrEnumerationType() &&
          !VD->getFirstDecl()->isOutOfLine() && VD->getFirstDecl()->hasInit();
 }
 
diff --git a/clang/test/CodeGenCXX/static-data-member.cpp b/clang/test/CodeGenCXX/static-data-member.cpp
index 5f4d9b6..5ffd83f 100644
--- a/clang/test/CodeGenCXX/static-data-member.cpp
+++ b/clang/test/CodeGenCXX/static-data-member.cpp
@@ -1,10 +1,6 @@
-// RUN: %clang_cc1 -triple x86_64-pc-linux -std=c++14 -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-apple-darwin -std=c++14 -emit-llvm -o - %s \
-// RUN:     | FileCheck %s --check-prefix=MACHO
-// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -std=c++14 -emit-llvm -o - %s \
-// RUN:     | FileCheck %s --check-prefix=MSVC
-// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc -std=c++17 -emit-llvm -o - %s \
-// RUN:     | FileCheck %s --check-prefix=MSVC
+// RUN: %clang_cc1 -triple x86_64-pc-linux -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm -o - %s | \
+// RUN: FileCheck --check-prefix=MACHO %s
 
 // CHECK: @_ZN5test11A1aE = constant i32 10, align 4
 // CHECK: @_ZN5test212_GLOBAL__N_11AIiE1xE = internal global i32 0, align 4
@@ -13,25 +9,12 @@
 // MACHO: @_ZGVN5test31AIiE1xE = weak_odr global i64 0
 // MACHO-NOT: comdat
 
-// MSVC: @"\01?a@A@test1@@2HB" = linkonce_odr constant i32 10, comdat, align 4
-// MSVC: @"\01?i@S@test1@@2HA" = external global i32
-// MSVC: @"\01?x@?$A@H@?A@test2@@2HA" = internal global i32 0, align 4
-
 // CHECK: _ZN5test51U2k0E = global i32 0
 // CHECK: _ZN5test51U2k1E = global i32 0
 // CHECK: _ZN5test51U2k2E = constant i32 76
 // CHECK-NOT: test51U2k3E
 // CHECK-NOT: test51U2k4E
 
-// On Linux in C++14, neither of these are inline.
-// CHECK: @_ZN16inline_constexpr1A10just_constE = available_externally constant i32 42
-// CHECK: @_ZN16inline_constexpr1A10const_exprE = available_externally constant i32 43
-//
-// In MSVC, these are both implicitly inline regardless of the C++ standard
-// version.
-// MSVC: @"\01?just_const@A@inline_constexpr@@2HB" = linkonce_odr constant i32 42, comdat, align 4
-// MSVC: @"\01?const_expr@A@inline_constexpr@@2HB" = linkonce_odr constant i32 43, comdat, align 4
-
 // PR5564.
 namespace test1 {
   struct A {
@@ -45,7 +28,7 @@ namespace test1 {
   };
 
   void f() { 
-    int a = *&A::a + S::i;
+    int a = S::i;
   }
 }
 
@@ -67,11 +50,6 @@ namespace test2 {
   // CHECK:      [[TMP:%.*]] = call i32 @_ZN5test23fooEv()
   // CHECK-NEXT: store i32 [[TMP]], i32* @_ZN5test212_GLOBAL__N_11AIiE1xE, align 4
   // CHECK-NEXT: ret void
-
-  // MSVC-LABEL: define internal void @"\01??__Ex@?$A@H@?A@test2@@2HA@YAXXZ"()
-  // MSVC:      [[TMP:%.*]] = call i32 @"\01?foo@test2@@YAHXZ"()
-  // MSVC-NEXT: store i32 [[TMP]], i32* @"\01?x@?$A@H@?A@test2@@2HA", align 4
-  // MSVC-NEXT: ret void
 }
 
 // Test that we don't use threadsafe statics when initializing
@@ -130,13 +108,3 @@ namespace test5 {
   // CHECK: store i32 {{.*}}, i32* @_ZN5test51U2k1E
   // CHECK-NOT: store {{.*}} i32* @_ZN5test51U2k2E
 }
-
-// Test that MSVC mode static constexpr data members are always inline, even pre
-// C++17.
-namespace inline_constexpr {
-struct A {
-  static const int just_const = 42;
-  static constexpr int const_expr = 43;
-};
-int useit() { return *&A::just_const + *&A::const_expr; }
-}
-- 
2.7.4