[ObjC++] Never pass structs that transitively contain __weak fields in

registers.

This patch fixes a bug in r328731 that caused structs transitively
containing __weak fields to be passed in registers. The patch replaces
the flag RecordDecl::CanPassInRegisters with a 2-bit enum that indicates
whether the struct or structs containing the struct are forced to be
passed indirectly.

This reapplies r329617. r329617 didn't specify the underlying type for
enum ArgPassingKind, which caused regression tests to fail on a windows
bot.

rdar://problem/39194693

Differential Revision: https://reviews.llvm.org/D45384

llvm-svn: 329635

1 files changed, 8 insertions, 1 deletions

diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index 99ff1ca31e7..dd653d8f573 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -421,6 +421,10 @@ CXXRecordDecl::setBases(CXXBaseSpecifier const * const *Bases,
     if (BaseClassDecl->hasVolatileMember())
       setHasVolatileMember(true);
 
+    if (BaseClassDecl->getArgPassingRestrictions() ==
+        RecordDecl::APK_CanNeverPassInRegs)
+      setArgPassingRestrictions(RecordDecl::APK_CanNeverPassInRegs);
+
     // Keep track of the presence of mutable fields.
     if (BaseClassDecl->hasMutableFields()) {
       data().HasMutableFields = true;
@@ -950,7 +954,7 @@ void CXXRecordDecl::addedMember(Decl *D) {
 
         // Structs with __weak fields should never be passed directly.
         if (LT == Qualifiers::OCL_Weak)
-          setCanPassInRegisters(false);
+          setArgPassingRestrictions(RecordDecl::APK_CanNeverPassInRegs);
 
         Data.HasIrrelevantDestructor = false;
       } else if (!Context.getLangOpts().ObjCAutoRefCount) {
@@ -1117,6 +1121,9 @@ void CXXRecordDecl::addedMember(Decl *D) {
           setHasObjectMember(true);
         if (FieldRec->hasVolatileMember())
           setHasVolatileMember(true);
+        if (FieldRec->getArgPassingRestrictions() ==
+            RecordDecl::APK_CanNeverPassInRegs)
+          setArgPassingRestrictions(RecordDecl::APK_CanNeverPassInRegs);
 
         // C++0x [class]p7:
         //   A standard-layout class is a class that: