From 515c67ee77f8d9c417efc0fe04615d269bfb70e4 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@apple.com>
Date: Fri, 4 Mar 2011 23:37:39 +0000
Subject: [PATCH] Support unregistering exception frames of functions when they
 are removed.

Patch by Johannes Schaub!

Fixes PR8548


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127047 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../llvm/ExecutionEngine/ExecutionEngine.h    | 20 ++++++++++++++++---
 lib/ExecutionEngine/ExecutionEngine.cpp       |  7 ++++---
 lib/ExecutionEngine/JIT/JITEmitter.cpp        |  7 ++++---
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/include/llvm/ExecutionEngine/ExecutionEngine.h b/include/llvm/ExecutionEngine/ExecutionEngine.h
index 71698fa0087..dcc9743d697 100644
--- a/include/llvm/ExecutionEngine/ExecutionEngine.h
+++ b/include/llvm/ExecutionEngine/ExecutionEngine.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/ValueMap.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/ValueHandle.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Target/TargetMachine.h"
@@ -161,7 +162,9 @@ protected:
   typedef void (*EERegisterFn)(void*);
   EERegisterFn ExceptionTableRegister;
   EERegisterFn ExceptionTableDeregister;
-  std::vector<void*> AllExceptionTables;
+  /// This maps functions to their exception tables frames.
+  DenseMap<const Function*, void*> AllExceptionTables;
+
 
 public:
   /// lock - This lock protects the ExecutionEngine, JIT, JITResolver and
@@ -410,10 +413,21 @@ public:
   
   /// RegisterTable - Registers the given pointer as an exception table.  It
   /// uses the ExceptionTableRegister function.
-  void RegisterTable(void* res) {
+  void RegisterTable(const Function *fn, void* res) {
     if (ExceptionTableRegister) {
       ExceptionTableRegister(res);
-      AllExceptionTables.push_back(res);
+      AllExceptionTables[fn] = res;
+    }
+  }
+
+  /// DeregisterTable - Deregisters the exception frame previously registered for the given function.
+  void DeregisterTable(const Function *Fn) {
+    if (ExceptionTableDeregister) {
+      DenseMap<const Function*, void*>::iterator frame = AllExceptionTables.find(Fn);
+      if(frame != AllExceptionTables.end()) {
+        ExceptionTableDeregister(frame->second);
+        AllExceptionTables.erase(frame);
+      }
     }
   }
 
diff --git a/lib/ExecutionEngine/ExecutionEngine.cpp b/lib/ExecutionEngine/ExecutionEngine.cpp
index f28697530b3..25a61c02890 100644
--- a/lib/ExecutionEngine/ExecutionEngine.cpp
+++ b/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -79,9 +79,10 @@ ExecutionEngine::~ExecutionEngine() {
 
 void ExecutionEngine::DeregisterAllTables() {
   if (ExceptionTableDeregister) {
-    for (std::vector<void*>::iterator it = AllExceptionTables.begin(),
-           ie = AllExceptionTables.end(); it != ie; ++it)
-      ExceptionTableDeregister(*it);
+    DenseMap<const Function*, void*>::iterator it = AllExceptionTables.begin();
+    DenseMap<const Function*, void*>::iterator ite = AllExceptionTables.end();
+    for (; it != ite; ++it)
+      ExceptionTableDeregister(it->second);
     AllExceptionTables.clear();
   }
 }
diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index 4cd8757ad0b..fa3c5a01c1e 100644
--- a/lib/ExecutionEngine/JIT/JITEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -985,7 +985,7 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
     CurBufferPtr = SavedCurBufferPtr;
 
     if (JITExceptionHandling) {
-      TheJIT->RegisterTable(FrameRegister);
+      TheJIT->RegisterTable(F.getFunction(), FrameRegister);
     }
 
     if (JITEmitDebugInfo) {
@@ -1033,8 +1033,9 @@ void JITEmitter::deallocateMemForFunction(const Function *F) {
     EmittedFunctions.erase(Emitted);
   }
 
-  // TODO: Do we need to unregister exception handling information from libgcc
-  // here?
+  if(JITExceptionHandling) {
+    TheJIT->DeregisterTable(F);
+  }
 
   if (JITEmitDebugInfo) {
     DR->UnregisterFunction(F);
-- 
2.34.1