From abf65bb14332a0955511ef1cca24a0a1647bee96 Mon Sep 17 00:00:00 2001
From: Arnold Schwaighofer <aschwaighofer@apple.com>
Date: Mon, 15 Jun 2020 15:16:06 -0700
Subject: [PATCH] IRGen: Use the right descriminator for
 AutoDiffDerivativeFunctions

Fixes the failure in AutoDiff/validation-test/forward_mode.swift on
arm64e.

rdar://64192250
---
 include/swift/SIL/SILDeclRef.h | 10 ++++++++++
 lib/IRGen/GenMeta.cpp          |  3 +++
 2 files changed, 13 insertions(+)

diff --git a/include/swift/SIL/SILDeclRef.h b/include/swift/SIL/SILDeclRef.h
index 1cb4c2d5b1b38..542435e3ef3ec 100644
--- a/include/swift/SIL/SILDeclRef.h
+++ b/include/swift/SIL/SILDeclRef.h
@@ -397,6 +397,16 @@ struct SILDeclRef {
 
   bool canBeDynamicReplacement() const;
 
+  bool isAutoDiffDerivativeFunction() const {
+    return derivativeFunctionIdentifier != nullptr;
+  }
+
+  AutoDiffDerivativeFunctionIdentifier *
+  getAutoDiffDerivativeFunctionIdentifier() const {
+    assert(isAutoDiffDerivativeFunction());
+    return derivativeFunctionIdentifier;
+  }
+
 private:
   friend struct llvm::DenseMapInfo<swift::SILDeclRef>;
   /// Produces a SILDeclRef from an opaque value.
diff --git a/lib/IRGen/GenMeta.cpp b/lib/IRGen/GenMeta.cpp
index 827f5991da022..a4db214165cee 100644
--- a/lib/IRGen/GenMeta.cpp
+++ b/lib/IRGen/GenMeta.cpp
@@ -739,6 +739,9 @@ namespace {
                            isa<ConstructorDecl>(func.getDecl())
                              ? SILDeclRef::Kind::Allocator
                              : SILDeclRef::Kind::Func);
+        if (entry.getFunction().isAutoDiffDerivativeFunction())
+          declRef = declRef.asAutoDiffDerivativeFunction(
+              entry.getFunction().getAutoDiffDerivativeFunctionIdentifier());
         addDiscriminator(flags, schema, declRef);
       }