[PATCH] D15225: [Driver] Sanitizer support based on runtime library presence

Kuba Brecka via cfe-commits cfe-commits at lists.llvm.org
Mon Jan 25 08:12:26 PST 2016

kubabrecka added inline comments.

Comment at: test/Driver/fsanitize.c:221
@@ +220,3 @@
+// RUN: %clang -target x86_64-apple-darwin10 -resource-dir=%S/Inputs/resource_dir -fsanitize=memory -fsanitize=thread,memory %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MSAN-TSAN-MSAN-DARWIN1
+// CHECK-MSAN-TSAN-MSAN-DARWIN1: unsupported option '-fsanitize=thread,memory' for target 'x86_64-apple-darwin10'
+// CHECK-MSAN-TSAN-MSAN-DARWIN1-NOT: unsupported option
ygribov wrote:
> samsonov wrote:
> > beanz wrote:
> > > kubabrecka wrote:
> > > > samsonov wrote:
> > > > > Again, I feel like we're lying to users here: `-fsanitize=thread` *is* supported for this target, it just requires building a runtime.
> > > > I'd like to see this from the point-of-view of a binary distribution.  If the binary distribution (e.g. the one from llvm.org or Apple's Clang in Xcode) doesn't contain a runtime library, then the sanitizer is *not* supported in that distribution.  Also, see http://reviews.llvm.org/D14846, we'd like to have CMake options to select which runtimes will be built.  If you deliberately choose not to build ThreadSanitizer, then that sanitizer is *not* supported in your version of Clang.  If you're experimenting and porting a runtime to a new platform, then this sanitizer *is* supported in your version of Clang.
> > > Maybe the point is we should have a different error message for cases where the runtime is just missing. Something like "runtime components for '-fsanitize=thread' not available"
> > I see, so essentially you want to use a different approach for determining sanitizer availability (on OS X for now): if the library is present, then we support sanitizer, otherwise we don't: i.e. the binary distribution is the source of truth, not the list of sanitizers hardcoded into Clang driver source code. I'm fine with that, and see why it would make sense.
> > 
> > It's just that error message looks misleading: the problem is not TSan is unsupported for target, it's just unavailable in this distribution for one reason or another.
> > the binary distribution is the source of truth, not the list of sanitizers hardcoded into Clang driver source code.
> This will not work for cross-compilers. It _may_ be ok for OSX but not for other platforms.
Why not?  On Linux, there are statically-linked sanitizers, if you want to cross-compile, you need to have the runtime libraries for the target.  And dynamic libraries are a similar story – they're version-tied to the compiler and your compiler should really have the libraries of the sanitizers that it supports.


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