NoExitRuntime

3 files changed, 99 insertions, 1 deletions

diff --git a/lib/Transforms/NaCl/CMakeLists.txt b/lib/Transforms/NaCl/CMakeLists.txt
index 31932a42bb..05cef0857e 100644
--- a/lib/Transforms/NaCl/CMakeLists.txt
+++ b/lib/Transforms/NaCl/CMakeLists.txt
@@ -31,6 +31,7 @@ add_llvm_library(LLVMNaClTransforms
   ExpandI64.cpp
   LowerEmExceptionsPass.cpp
   LowerEmSetjmp.cpp
+  NoExitRuntime.cpp
   )
 
 add_dependencies(LLVMNaClTransforms intrinsics_gen)
diff --git a/lib/Transforms/NaCl/LowerEmSetjmp.cpp b/lib/Transforms/NaCl/LowerEmSetjmp.cpp
index 469bf02daf..0a22d122bc 100644
--- a/lib/Transforms/NaCl/LowerEmSetjmp.cpp
+++ b/lib/Transforms/NaCl/LowerEmSetjmp.cpp
@@ -297,7 +297,7 @@ bool LowerEmSetjmp::runOnModule(Module &M) {
     }
   }
 
-  for (int i = 0; i < ToErase.size(); i++) {
+  for (unsigned i = 0; i < ToErase.size(); i++) {
     ToErase[i]->eraseFromParent();
   }
 
diff --git a/lib/Transforms/NaCl/NoExitRuntime.cpp b/lib/Transforms/NaCl/NoExitRuntime.cpp
new file mode 100644
index 0000000000..ca622d3c06
--- /dev/null
+++ b/lib/Transforms/NaCl/NoExitRuntime.cpp
@@ -0,0 +1,97 @@
+//===- NoExitRuntime.cpp - Expand i64 and wider integer types -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===------------------------------------------------------------------===//
+//
+//===------------------------------------------------------------------===//
+
+#include "llvm/ADT/PostOrderIterator.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/NaCl.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include <map>
+
+#include "llvm/Support/raw_ostream.h"
+
+#ifdef NDEBUG
+#undef assert
+#define assert(x) { if (!(x)) report_fatal_error(#x); }
+#endif
+
+using namespace llvm;
+
+namespace {
+  class NoExitRuntime : public ModulePass {
+    Module *TheModule;
+
+  public:
+    static char ID;
+    NoExitRuntime() : ModulePass(ID) {
+      initializeNoExitRuntimePass(*PassRegistry::getPassRegistry());
+    }
+
+    virtual bool runOnModule(Module &M);
+  };
+}
+
+char NoExitRuntime::ID = 0;
+INITIALIZE_PASS(NoExitRuntime, "emscripten-no-exit-runtime",
+                "Generate code which assumes the runtime is never exited (so atexit etc. is unneeded; see emscripten NO_EXIT_RUNTIME setting)",
+                false, false)
+
+
+// Implementation of NoExitRuntime
+
+bool NoExitRuntime::runOnModule(Module &M) {
+  TheModule = &M;
+
+  Function *AtExit = TheModule->getFunction("__cxa_atexit");
+  if (!AtExit || !AtExit->isDeclaration() || AtExit->getNumUses() == 0) return false;
+
+  // The system atexit is used - let's remove calls to it
+
+  Type *i32 = Type::getInt32Ty(TheModule->getContext());
+  Value *Zero  = Constant::getNullValue(i32);
+
+  std::vector<Instruction*> ToErase;
+
+  for (Instruction::use_iterator UI = AtExit->use_begin(), UE = AtExit->use_end(); UI != UE; ++UI) {
+    if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
+      if (CI->getCalledValue() == AtExit) {
+        // calls to atexit can just be removed
+        CI->replaceAllUsesWith(Zero);
+        ToErase.push_back(CI);
+        continue;
+      }
+    }
+    // Possibly other uses of atexit are done - ptrtoint, etc. - but we leave those alone
+  }
+
+  for (unsigned i = 0; i < ToErase.size(); i++) {
+    ToErase[i]->eraseFromParent();
+  }
+
+  return true;
+}
+
+ModulePass *llvm::createNoExitRuntimePass() {
+  return new NoExitRuntime();
+}
+