lli: [MCJIT] Suppress "__main" for cygming in LLIMCJITMemoryManager::getPointerToName...

CRT's __main (aka premain) invokes global ctors on cygming. See also PR3897.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165312 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/tools/lli/lli.cpp b/tools/lli/lli.cpp
index c5645ec..57a31f2 100644 (file)
--- a/tools/lli/lli.cpp
+++ b/tools/lli/lli.cpp
@@ -338,6 +338,10 @@ void LLIMCJITMemoryManager::invalidateInstructionCache() {
                                             AllocatedCodeMem[i].size());
 }
 
+static int jit_noop() {
+  return 0;
+}
+
 void *LLIMCJITMemoryManager::getPointerToNamedFunction(const std::string &Name,
                                                        bool AbortOnFailure) {
 #if defined(__linux__)
@@ -360,6 +364,14 @@ void *LLIMCJITMemoryManager::getPointerToNamedFunction(const std::string &Name,
   if (Name == "mknod") return (void*)(intptr_t)&mknod;
 #endif // __linux__
 
+  // We should not invoke parent's ctors/dtors from generated main()!
+  // On Mingw and Cygwin, the symbol __main is resolved to
+  // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
+  // (and register wrong callee's dtors with atexit(3)).
+  // We expect ExecutionEngine::runStaticConstructorsDestructors()
+  // is called before ExecutionEngine::runFunctionAsMain() is called.
+  if (Name == "__main") return (void*)(intptr_t)&jit_noop;
+
   const char *NameStr = Name.c_str();
   void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
   if (Ptr) return Ptr;