From da267435763601112f64ae02f6e81306723c4858 Mon Sep 17 00:00:00 2001
From: Axel Naumann <Axel.Naumann@cern.ch>
Date: Thu, 12 Jan 2023 14:01:20 +0100
Subject: [PATCH] [cling] JIT: only re-use *large* existing weak functions:
Small functions might get inlined, and hiding their definition prevents
the inliner from doing its job.
---
interpreter/cling/lib/Interpreter/BackendPasses.cpp | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/interpreter/cling/lib/Interpreter/BackendPasses.cpp b/interpreter/cling/lib/Interpreter/BackendPasses.cpp
index 74b246a5f6d..2282019dec1 100644
--- a/interpreter/cling/lib/Interpreter/BackendPasses.cpp
+++ b/interpreter/cling/lib/Interpreter/BackendPasses.cpp
@@ -267,6 +267,15 @@ namespace {
// GV is a definition.
+ if (auto *Func = dyn_cast<Function>(&GV))
+ if (Func->getInstructionCount() < 50) {
+ // This is a small function. Keep its definition to retain it for
+ // inlining: the cost for JITting it is small, and the likelihood
+ // that the call will be inlined is high.
+ return false;
+ }
+
+
llvm::GlobalValue::LinkageTypes LT = GV.getLinkage();
if (!GV.isDiscardableIfUnused(LT) || !GV.isWeakForLinker(LT))
return false;
--
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