1. Tidy up jump table info.

[oota-llvm.git] / lib / ExecutionEngine / JIT / Intercept.cpp

diff --git a/lib/ExecutionEngine/JIT/Intercept.cpp b/lib/ExecutionEngine/JIT/Intercept.cpp
index 6162e938aba717c56bdbcf7322823ce6f89b5995..f370e5bb0a83a84f3d0e4484c75cdb289007cae7 100644 (file)
--- a/lib/ExecutionEngine/JIT/Intercept.cpp
+++ b/lib/ExecutionEngine/JIT/Intercept.cpp
@@ -1,10 +1,10 @@
 //===-- Intercept.cpp - System function interception routines -------------===//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
 // This file was developed by the LLVM research group and is distributed under
 // the University of Illinois Open Source License. See LICENSE.TXT for details.
-// 
+//
 //===----------------------------------------------------------------------===//
 //
 // If a function call occurs to an external function, the JIT is designed to use
@@ -15,9 +15,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "VM.h"
-#include "Support/DynamicLinker.h"
-#include <iostream>
+#include "JIT.h"
+#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Config/config.h"
+using namespace llvm;
 
 // AtExitHandlers - List of functions to call when the program exits,
 // registered with the atexit() library function.
@@ -27,7 +28,7 @@ static std::vector<void (*)()> AtExitHandlers;
 /// calls to atexit(3), which we intercept and store in
 /// AtExitHandlers.
 ///
-void VM::runAtExitHandlers() {
+static void runAtExitHandlers() {
   while (!AtExitHandlers.empty()) {
     void (*Fn)() = AtExitHandlers.back();
     AtExitHandlers.pop_back();
@@ -39,12 +40,39 @@ void VM::runAtExitHandlers() {
 // Function stubs that are invoked instead of certain library calls
 //===----------------------------------------------------------------------===//
 
-// NoopFn - Used if we have nothing else to call...
-static void NoopFn() {}
+// Force the following functions to be linked in to anything that uses the
+// JIT. This is a hack designed to work around the all-too-clever Glibc
+// strategy of making these functions work differently when inlined vs. when
+// not inlined, and hiding their real definitions in a separate archive file
+// that the dynamic linker can't see. For more info, search for
+// 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
+#if defined(__linux__)
+#if defined(HAVE_SYS_STAT_H)
+#include <sys/stat.h>
+#endif
+void *FunctionPointers[] = {
+  (void *)(intptr_t) stat,
+  (void *)(intptr_t) fstat,
+  (void *)(intptr_t) lstat,
+  (void *)(intptr_t) stat64,
+  (void *)(intptr_t) fstat64,
+  (void *)(intptr_t) lstat64,
+  (void *)(intptr_t) atexit,
+  (void *)(intptr_t) mknod
+};
+#endif // __linux__
+
+// __mainFunc - If the program does not have a linked in __main function, allow
+// it to run, but print a warning.
+static void __mainFunc() {
+  fprintf(stderr, "WARNING: Program called __main but was not linked to "
+          "libcrtend.a.\nThis probably won't hurt anything unless the "
+          "program is written in C++.\n");
+}
 
 // jit_exit - Used to intercept the "exit" library call.
 static void jit_exit(int Status) {
-  VM::runAtExitHandlers();   // Run atexit handlers...
+  runAtExitHandlers();   // Run atexit handlers...
   exit(Status);
 }
 
@@ -55,23 +83,39 @@ static int jit_atexit(void (*Fn)(void)) {
 }
 
 //===----------------------------------------------------------------------===//
-// 
+//
 /// getPointerToNamedFunction - This method returns the address of the specified
-/// function by using the dynamic loader interface.  As such it is only useful 
+/// function by using the dynamic loader interface.  As such it is only useful
 /// for resolving library symbols, not code generated symbols.
 ///
-void *VM::getPointerToNamedFunction(const std::string &Name) {
-  // Check to see if this is one of the functions we want to intercept...
-  if (Name == "exit") return (void*)&jit_exit;
-  if (Name == "atexit") return (void*)&jit_atexit;
+void *JIT::getPointerToNamedFunction(const std::string &Name) {
+  // Check to see if this is one of the functions we want to intercept.  Note,
+  // we cast to intptr_t here to silence a -pedantic warning that complains
+  // about casting a function pointer to a normal pointer.
+  if (Name == "exit") return (void*)(intptr_t)&jit_exit;
+  if (Name == "atexit") return (void*)(intptr_t)&jit_atexit;
 
+  // If the program does not have a linked in __main function, allow it to run,
+  // but print a warning.
+  if (Name == "__main") return (void*)(intptr_t)&__mainFunc;
+
+  const char *NameStr = Name.c_str();
+  // If this is an asm specifier, skip the sentinal.
+  if (NameStr[0] == 1) ++NameStr;
+  
   // If it's an external function, look it up in the process image...
-  void *Ptr = GetAddressOfSymbol(Name);
-  if (Ptr == 0) {
-    std::cerr << "WARNING: Cannot resolve fn '" << Name
-             << "' using a dummy noop function instead!\n";
-    Ptr = (void*)NoopFn;
-  }
+  void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
+  if (Ptr) return Ptr;
   
-  return Ptr;
+  // If it wasn't found and if it starts with an underscore ('_') character, and
+  // has an asm specifier, try again without the underscore.
+  if (Name[0] == 1 && NameStr[0] == '_') {
+    Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr+1);
+    if (Ptr) return Ptr;
+  }
+
+  cerr << "ERROR: Program used external function '" << Name
+       << "' which could not be resolved!\n";
+  abort();
+  return 0;
 }