From 7266a8bfeb85efba30f942a89d257d6f94ca1811 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Thu, 12 Mar 2020 14:44:53 -0700
Subject: [PATCH] [ORC] Enable exception handling in JIT'd code when using
 LLJIT on Darwin.

This patch enables exception handling in code added to LLJIT on Darwin by
adding an orc::EHFrameRegistrationPlugin instance to the ObjectLinkingLayer
(which is currently used on Darwin only).
---
 llvm/lib/ExecutionEngine/Orc/LLJIT.cpp        |  6 +-
 .../OrcLazy/minimal-throw-catch.ll            | 58 +++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/ExecutionEngine/OrcLazy/minimal-throw-catch.ll

diff --git a/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp b/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
index a847f0ef9421..cfb1bb8c7eab 100644
--- a/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/LLJIT.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ExecutionEngine/Orc/LLJIT.h"
+#include "llvm/ExecutionEngine/JITLink/EHFrameSupport.h"
 #include "llvm/ExecutionEngine/JITLink/JITLinkMemoryManager.h"
 #include "llvm/ExecutionEngine/Orc/MachOPlatform.h"
 #include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
@@ -923,8 +924,11 @@ Error LLJITBuilderState::prepareForConstruction() {
       CreateObjectLinkingLayer =
           [](ExecutionSession &ES,
              const Triple &) -> std::unique_ptr<ObjectLayer> {
-        return std::make_unique<ObjectLinkingLayer>(
+        auto ObjLinkingLayer = std::make_unique<ObjectLinkingLayer>(
             ES, std::make_unique<jitlink::InProcessMemoryManager>());
+        ObjLinkingLayer->addPlugin(std::make_unique<EHFrameRegistrationPlugin>(
+            jitlink::InProcessEHFrameRegistrar::getInstance()));
+        return ObjLinkingLayer;
       };
     }
   }
diff --git a/llvm/test/ExecutionEngine/OrcLazy/minimal-throw-catch.ll b/llvm/test/ExecutionEngine/OrcLazy/minimal-throw-catch.ll
new file mode 100644
index 000000000000..55dbc062e8e5
--- /dev/null
+++ b/llvm/test/ExecutionEngine/OrcLazy/minimal-throw-catch.ll
@@ -0,0 +1,58 @@
+; REQUIRES: system-darwin
+; RUN: lli -jit-kind=orc-lazy %s
+;
+; Sanity test eh-frame processing and registration.
+
+source_filename = "minimal-throw-catch.cpp"
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.14.0"
+
+@_ZTIi = external constant i8*
+
+declare i8* @__cxa_allocate_exception(i64)
+declare void @__cxa_throw(i8*, i8*, i8*)
+
+declare i32 @__gxx_personality_v0(...)
+declare i32 @llvm.eh.typeid.for(i8*)
+declare i8* @__cxa_begin_catch(i8*)
+declare void @__cxa_end_catch()
+
+define void @explode() {
+entry:
+  %exception = tail call i8* @__cxa_allocate_exception(i64 4)
+  %0 = bitcast i8* %exception to i32*
+  store i32 42, i32* %0, align 16
+  tail call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null)
+  unreachable
+}
+
+define i32 @main(i32 %argc, i8** %argv) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  invoke void @explode()
+          to label %return unwind label %lpad
+
+lpad:
+  %0 = landingpad { i8*, i32 }
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+  %1 = extractvalue { i8*, i32 } %0, 1
+  %2 = tail call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %1, %2
+  br i1 %matches, label %catch, label %eh.resume
+
+catch:
+  %3 = extractvalue { i8*, i32 } %0, 0
+  %4 = tail call i8* @__cxa_begin_catch(i8* %3)
+  %5 = bitcast i8* %4 to i32*
+  %6 = load i32, i32* %5, align 4
+  %cmp = icmp ne i32 %6, 42
+  %cond = zext i1 %cmp to i32
+  tail call void @__cxa_end_catch()
+  br label %return
+
+return:
+  %retval.0 = phi i32 [ %cond, %catch ], [ 2, %entry ]
+  ret i32 %retval.0
+
+eh.resume:
+  resume { i8*, i32 } %0
+}