[llvm-commits] [PATCH] Add -fcatch-undefined-behavior runtime library

[PaX Team]

On 4 Oct 2012 at 1:36, Richard Smith wrote:

> Hi,
> 
> The attached patches to compiler-rt and Clang add a new runtime library
> which -fcatch-undefined-behavior will call into when it detects undefined
> behavior.

Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp	(revision 164853)
+++ lib/Driver/Tools.cpp	(working copy)
@@ -1458,6 +1458,23 @@
   }
 }

+/// If UndefinedBehaviorSanitizer is enabled, add appropriate linker flags
+/// (Linux).
+static void addUbsanRTLinux(const ToolChain &TC, const ArgList &Args,
+                            ArgStringList &CmdArgs) {
+  if (!Args.hasArg(options::OPT_fcatch_undefined_behavior))
+    return;
+  if (!Args.hasArg(options::OPT_shared)) {
+    // LibUbsan is "libclang_rt.ubsan-<ArchName>.a" in the Linux library
+    // resource directory.
+    SmallString<128> LibUbsan(TC.getDriver().ResourceDir);
+    llvm::sys::path::append(LibUbsan, "lib", "linux",
+                            (Twine("libclang_rt.ubsan-") +
+                             TC.getArchName() + ".a"));
+    CmdArgs.push_back(Args.MakeArgString(LibUbsan));
+  }
+}

would it be possible to check for -ffreestanding here and not add the library
forcibly in that case? i'm (once again ;) thinking of a kernel environment here
where using such a library may not be an option (no c++ allowed for one) and the
kernel would like to handle these functions in its own way (much like it handles
memcpy, etc already).

cheers,
  PaX Team