diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -39,6 +39,7 @@
 #include "clang/Basic/SanitizerBlacklist.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Specifiers.h"
+#include "clang/Basic/TargetCXXABI.h"
 #include "clang/Basic/XRayLists.h"
 #include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -697,6 +698,11 @@
     return FullSourceLoc(Loc,SourceMgr);
   }
 
+  /// Return the C++ ABI kind that should be used. This is located here so the
+  /// ABI can be overriden by Clang-specific flags at compile-time. If there are
+  /// no overrides, we instead use the default ABI specified by the target.
+  TargetCXXABI::Kind getCXXABIKind(const TargetInfo *T = nullptr) const;
+
   /// All comments in this translation unit.
   RawCommentList Comments;
 
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -879,10 +879,18 @@
   return CanonTTP;
 }
 
+TargetCXXABI::Kind ASTContext::getCXXABIKind(const TargetInfo *T) const {
+  const auto &Target = T ? *T : getTargetInfo();
+  if (Target.getTriple().isOSFuchsia() &&
+      Target.getTriple().getEnvironment() == llvm::Triple::GNU)
+    return TargetCXXABI::GenericItanium;
+  return Target.getCXXABI().getKind();
+}
+
 CXXABI *ASTContext::createCXXABI(const TargetInfo &T) {
   if (!LangOpts.CPlusPlus) return nullptr;
 
-  switch (T.getCXXABI().getKind()) {
+  switch (getCXXABIKind(&T)) {
   case TargetCXXABI::AppleARM64:
   case TargetCXXABI::Fuchsia:
   case TargetCXXABI::GenericARM: // Same as Itanium at this level
@@ -10870,7 +10878,7 @@
 MangleContext *ASTContext::createMangleContext(const TargetInfo *T) {
   if (!T)
     T = Target;
-  switch (T->getCXXABI().getKind()) {
+  switch (getCXXABIKind(T)) {
   case TargetCXXABI::AppleARM64:
   case TargetCXXABI::Fuchsia:
   case TargetCXXABI::GenericAArch64:
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -75,7 +75,7 @@
 static const char AnnotationSection[] = "llvm.metadata";
 
 static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
-  switch (CGM.getTarget().getCXXABI().getKind()) {
+  switch (CGM.getContext().getCXXABIKind()) {
   case TargetCXXABI::AppleARM64:
   case TargetCXXABI::Fuchsia:
   case TargetCXXABI::GenericAArch64:
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -543,7 +543,7 @@
 }
 
 CodeGen::CGCXXABI *CodeGen::CreateItaniumCXXABI(CodeGenModule &CGM) {
-  switch (CGM.getTarget().getCXXABI().getKind()) {
+  switch (CGM.getContext().getCXXABIKind()) {
   // For IR-generation purposes, there's no significant difference
   // between the ARM and iOS ABIs.
   case TargetCXXABI::GenericARM:
diff --git a/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp b/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
--- a/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
+++ b/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
@@ -5,6 +5,8 @@
 //RUN:   | FileCheck --check-prefix=CHECKARM %s
 //RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-unknown-fuchsia | FileCheck --check-prefix=CHECKFUCHSIA %s
 //RUN: %clang_cc1 %s -emit-llvm -o - -triple=aarch64-unknown-fuchsia | FileCheck --check-prefix=CHECKFUCHSIA %s
+//RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-unknown-fuchsia-gnu | FileCheck --check-prefix=CHECKGEN_64 %s
+//RUN: %clang_cc1 %s -emit-llvm -o - -triple=aarch64-unknown-fuchsia-gnu | FileCheck --check-prefix=CHECKGEN_64 %s
 //RUN: %clang_cc1 %s -emit-llvm -o - -triple=i386-pc-win32 -fno-rtti | FileCheck --check-prefix=CHECKMS %s
 // FIXME: these tests crash on the bots when run with -triple=x86_64-pc-win32
 
@@ -52,6 +54,11 @@
 // CHECKFUCHSIA-LABEL: define{{.*}} %class.B* @_ZN1BD2Ev(%class.B* {{[^,]*}} returned {{[^,]*}} %this)
 // CHECKFUCHSIA-LABEL: define{{.*}} %class.B* @_ZN1BD1Ev(%class.B* {{[^,]*}} returned {{[^,]*}} %this)
 
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1BC2EPi(%class.B* {{[^,]*}} %this, i32* %i)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1BC1EPi(%class.B* {{[^,]*}} %this, i32* %i)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1BD2Ev(%class.B* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1BD1Ev(%class.B* {{[^,]*}} %this)
+
 // CHECKMS-LABEL: define dso_local x86_thiscallcc %class.B* @"??0B@@QAE@PAH@Z"(%class.B* {{[^,]*}} returned {{[^,]*}} %this, i32* %i)
 // CHECKMS-LABEL: define dso_local x86_thiscallcc void @"??1B@@UAE@XZ"(%class.B* {{[^,]*}} %this)
 
@@ -98,6 +105,14 @@
 // CHECKFUCHSIA-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
 // CHECKFUCHSIA-LABEL: define{{.*}} void @_ZThn16_N1CD0Ev(%class.C* {{[^,]*}} %this)
 
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1CC2EPiPc(%class.C* {{[^,]*}} %this, i32* %i, i8* %c)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1CC1EPiPc(%class.C* {{[^,]*}} %this, i32* %i, i8* %c)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1CD2Ev(%class.C* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1CD1Ev(%class.C* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZThn16_N1CD1Ev(%class.C* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZThn16_N1CD0Ev(%class.C* {{[^,]*}} %this)
+
 // CHECKMS-LABEL: define dso_local x86_thiscallcc %class.C* @"??0C@@QAE@PAHPAD@Z"(%class.C* {{[^,]*}} returned {{[^,]*}} %this, i32* %i, i8* %c)
 // CHECKMS-LABEL: define dso_local x86_thiscallcc void @"??1C@@UAE@XZ"(%class.C* {{[^,]*}} %this)
 
@@ -130,6 +145,11 @@
 // CHECKFUCHSIA-LABEL: define{{.*}} %class.D* @_ZN1DD2Ev(%class.D* {{[^,]*}} returned {{[^,]*}} %this, i8** %vtt)
 // CHECKFUCHSIA-LABEL: define{{.*}} %class.D* @_ZN1DD1Ev(%class.D* {{[^,]*}} returned {{[^,]*}} %this)
 
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1DC2Ev(%class.D* {{[^,]*}} %this, i8** %vtt)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1DC1Ev(%class.D* {{[^,]*}} %this)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1DD2Ev(%class.D* {{[^,]*}} %this, i8** %vtt)
+// CHECKGEN_64-LABEL: define{{.*}} void @_ZN1DD1Ev(%class.D* {{[^,]*}} %this)
+
 // CHECKMS-LABEL: define dso_local x86_thiscallcc %class.D* @"??0D@@QAE@XZ"(%class.D* {{[^,]*}} returned {{[^,]*}} %this, i32 %is_most_derived)
 // CHECKMS-LABEL: define dso_local x86_thiscallcc void @"??1D@@UAE@XZ"(%class.D* {{[^,]*}} %this)