Implement a function to print a warning if bytecode output is to be sent to

a terminal/console.

llvm-svn: 19237

2 files changed, 16 insertions, 11 deletions

diff --git a/llvm/include/llvm/Support/SystemUtils.h b/llvm/include/llvm/Support/SystemUtils.h
index decc3c4a3d4..856bc20b7c7 100644
--- a/llvm/include/llvm/Support/SystemUtils.h
+++ b/llvm/include/llvm/Support/SystemUtils.h
@@ -19,9 +19,12 @@
 
 namespace llvm {
 
-/// isStandardOutAConsole - Return true if we can tell that the standard output
-/// stream goes to a terminal window or console.
-bool isStandardOutAConsole();
+/// Determine if the ostream provided is connected to the std::cout and 
+/// displayed or not (to a console window). If so, generate a warning message 
+/// advising against display of bytecode and return true. Otherwise just return
+/// false
+/// @brief Check for output written to a console
+bool CheckBytecodeOutputToConsole(std::ostream* stream_to_check);
 
 /// FindExecutable - Find a named executable, giving the argv[0] of program
 /// being executed. This allows us to find another LLVM tool if it is built into
diff --git a/llvm/lib/Support/SystemUtils.cpp b/llvm/lib/Support/SystemUtils.cpp
index 4213b84b8bd..dfb87755f7b 100644
--- a/llvm/lib/Support/SystemUtils.cpp
+++ b/llvm/lib/Support/SystemUtils.cpp
@@ -14,20 +14,22 @@
 
 #include "llvm/Support/SystemUtils.h"
 #include "llvm/System/Program.h"
+#include "llvm/System/Process.h"
+#include <iostream>
 
 using namespace llvm;
 
-/// isStandardOutAConsole - Return true if we can tell that the standard output
-/// stream goes to a terminal window or console.
-bool llvm::isStandardOutAConsole() {
-#if HAVE_ISATTY
-  return isatty(1);
-#endif
-  // If we don't have isatty, just return false.
+bool llvm::CheckBytecodeOutputToConsole(std::ostream* stream_to_check) {
+  if (stream_to_check == &std::cout && sys::Process::StandardOutIsDisplayed()) {
+    std::cerr << "WARNING: You're attempting to print out a bytecode file.\n";
+    std::cerr << "This is inadvisable as it may cause display problems. If\n";
+    std::cerr << "you REALLY want to taste LLVM bytecode first-hand, you can\n";
+    std::cerr << "force output with the `-f' option.\n\n";
+    return true;
+  }
   return false;
 }
 
-
 /// FindExecutable - Find a named executable, giving the argv[0] of program
 /// being executed. This allows us to find another LLVM tool if it is built
 /// into the same directory, but that directory is neither the current