opengl_varying crashes with Failed to free device buffer

[abestephensg]

In master and glsl-varyingattrib:

Each test case in opengl_varying passes but the test crashes on exit. If the tests cases are run individually, the error does not occur.

$ HL_JIT_TARGET=host-opengl opengl_varying
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
'+fma +f16c' is not a recognized feature for this target (ignoring feature)
Success!
Error:
Failed to free device buffer
#2 0x0000000101de0e7b in raise at /Users/abstephens/llvm-trunk/lib/Support/Unix/Signals.inc:518
#3 0x0000000101de0f32 in abort at /Users/abstephens/llvm-trunk/lib/Support/Unix/Signals.inc:535
#4 0x00000001001d44df in Halide::Internal::ErrorReport::explode() at /Users/abstephens/Halide-master/src/Error.cpp:67
#5 0x000000010000891c in Halide::Internal::ErrorReport::~ErrorReport() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:791
#6 0x00000001000088e5 in Halide::Internal::ErrorReport::~ErrorReport() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:785
#7 0x00000001000751aa in void Halide::Internal::destroyHalide::Internal::BufferContents(Halide::Internal::BufferContents const*) at /Users/abstephens/Halide-master/src/Buffer.cpp:112
#8 0x0000000100007d76 in Halide::Internal::IntrusivePtrHalide::Internal::BufferContents::decref(Halide::Internal::BufferContents*) at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:1143
#9 0x0000000100007d04 in Halide::Internal::IntrusivePtrHalide::Internal::BufferContents::~IntrusivePtr() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:1152
#10 0x0000000100007ce5 in Halide::Internal::IntrusivePtrHalide::Internal::BufferContents::~IntrusivePtr() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:1151
#11 0x0000000100007cc5 in Halide::Buffer::~Buffer() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:1214
#12 0x0000000100007ca5 in Halide::Buffer::~Buffer() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:1214
#13 0x000000010000ec15 in Halide::ImageBase::~ImageBase() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:8011
#14 0x000000010000ebf5 in Halide::Image::~Image() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:8151
#15 0x0000000100007375 in Halide::Image::~Image() at /Users/abstephens/Halide-master/build-xcode/include/Halide.h:8151
#16 0x0000000100004982 in main at /Users/abstephens/Halide-master/test/opengl/varying.cpp:176
#17 0x00007fff863475fd in start ()

[abestephensg]

It appears that the runtime calls halide_opengl_create_context for each Func realization, and then obtains texture number "1" in each context. When the program terminates, the appropriate context is not made current before each call to glDeleteTextures.