diff --git a/boehmgc-coroutine-sp-fallback.diff b/boehmgc-coroutine-sp-fallback.diff
index 2826486fb..5066d8278 100644
--- a/boehmgc-coroutine-sp-fallback.diff
+++ b/boehmgc-coroutine-sp-fallback.diff
@@ -1,8 +1,8 @@
diff --git a/darwin_stop_world.c b/darwin_stop_world.c
-index 3dbaa3fb..36a1d1f7 100644
+index 0468aaec..b348d869 100644
--- a/darwin_stop_world.c
+++ b/darwin_stop_world.c
-@@ -352,6 +352,7 @@ GC_INNER void GC_push_all_stacks(void)
+@@ -356,6 +356,7 @@ GC_INNER void GC_push_all_stacks(void)
int nthreads = 0;
word total_size = 0;
mach_msg_type_number_t listcount = (mach_msg_type_number_t)THREAD_TABLE_SZ;
@@ -10,7 +10,7 @@ index 3dbaa3fb..36a1d1f7 100644
if (!EXPECT(GC_thr_initialized, TRUE))
GC_thr_init();
-@@ -407,6 +408,19 @@ GC_INNER void GC_push_all_stacks(void)
+@@ -411,6 +412,19 @@ GC_INNER void GC_push_all_stacks(void)
GC_push_all_stack_sections(lo, hi, p->traced_stack_sect);
}
if (altstack_lo) {
@@ -30,6 +30,22 @@ index 3dbaa3fb..36a1d1f7 100644
total_size += altstack_hi - altstack_lo;
GC_push_all_stack(altstack_lo, altstack_hi);
}
+diff --git a/include/gc.h b/include/gc.h
+index edab6c22..f2c61282 100644
+--- a/include/gc.h
++++ b/include/gc.h
+@@ -2172,6 +2172,11 @@ GC_API void GC_CALL GC_win32_free_heap(void);
+ (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
+ #endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
+
++#if !__APPLE__
++/* Patch doesn't work on apple */
++#define NIX_BOEHM_PATCH_VERSION 1
++#endif
++
+ #ifdef __cplusplus
+ } /* extern "C" */
+ #endif
diff --git a/pthread_stop_world.c b/pthread_stop_world.c
index b5d71e62..aed7b0bf 100644
--- a/pthread_stop_world.c
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 2721b6733..3e8857fc8 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -325,6 +325,22 @@ static Symbol getName(const AttrName & name, EvalState & state, Env & env)
}
}
+#if HAVE_BOEHMGC
+/* Disable GC while this object lives. Used by CoroutineContext.
+ *
+ * Boehm keeps a count of GC_disable() and GC_enable() calls,
+ * and only enables GC when the count matches.
+ */
+class BoehmDisableGC {
+public:
+ BoehmDisableGC() {
+ GC_disable();
+ };
+ ~BoehmDisableGC() {
+ GC_enable();
+ };
+};
+#endif
static bool gcInitialised = false;
@@ -349,6 +365,15 @@ void initGC()
StackAllocator::defaultAllocator = &boehmGCStackAllocator;
+
+#if NIX_BOEHM_PATCH_VERSION != 1
+ printTalkative("Unpatched BoehmGC, disabling GC inside coroutines");
+ /* Used to disable GC when entering coroutines on macOS */
+ create_coro_gc_hook = []() -> std::shared_ptr<void> {
+ return std::make_shared<BoehmDisableGC>();
+ };
+#endif
+
/* Set the initial heap size to something fairly big (25% of
physical RAM, up to a maximum of 384 MiB) so that in most cases
we don't need to garbage collect at all. (Collection has a
diff --git a/src/libexpr/tests/coro-gc.cc b/src/libexpr/tests/coro-gc.cc
new file mode 100644
index 000000000..f848bc2f0
--- /dev/null
+++ b/src/libexpr/tests/coro-gc.cc
@@ -0,0 +1,147 @@
+#include <gtest/gtest.h>
+#if HAVE_BOEHMGC
+#include <gc/gc.h>
+
+#include "eval.hh"
+#include "serialise.hh"
+
+#endif
+
+
+namespace nix {
+#if HAVE_BOEHMGC
+
+ static void finalizer(void *obj, void *data) {
+ *((bool*)data) = true;
+ }
+
+ static bool* make_witness(volatile void* obj) {
+ /* We can't store the witnesses on the stack,
+ since they might be collected long afterwards */
+ bool* res = (bool*)GC_MALLOC_UNCOLLECTABLE(1);
+ *res = false;
+ GC_register_finalizer((void*)obj, finalizer, res, nullptr, nullptr);
+ return res;
+ }
+
+ // Generate 2 objects, discard one, run gc,
+ // see if one got collected and the other didn't
+ // GC is disabled inside coroutines on __APPLE__
+ static void testFinalizerCalls() {
+ volatile void* do_collect = GC_MALLOC_ATOMIC(128);
+ volatile void* dont_collect = GC_MALLOC_ATOMIC(128);
+
+ bool* do_collect_witness = make_witness(do_collect);
+ bool* dont_collect_witness = make_witness(dont_collect);
+ GC_gcollect();
+ GC_invoke_finalizers();
+
+ ASSERT_TRUE(GC_is_disabled() || *do_collect_witness);
+ ASSERT_FALSE(*dont_collect_witness);
+ ASSERT_NE(nullptr, dont_collect);
+ }
+
+ TEST(CoroGC, BasicFinalizers) {
+ initGC();
+ testFinalizerCalls();
+ }
+
+ // Run testFinalizerCalls inside a coroutine
+ // this tests that GC works as expected inside a coroutine
+ TEST(CoroGC, CoroFinalizers) {
+ initGC();
+
+ auto source = sinkToSource([&](Sink& sink) {
+ testFinalizerCalls();
+
+ // pass control to main
+ writeString("foo", sink);
+ });
+
+ // pass control to coroutine
+ std::string foo = readString(*source);
+ ASSERT_EQ(foo, "foo");
+ }
+
+#if __APPLE__
+ // This test tests that GC is disabled on darwin
+ // to work around the patch not being sufficient there,
+ // causing crashes whenever gc is invoked inside a coroutine
+ TEST(CoroGC, AppleCoroDisablesGC) {
+ initGC();
+ auto source = sinkToSource([&](Sink& sink) {
+ ASSERT_TRUE(GC_is_disabled());
+ // pass control to main
+ writeString("foo", sink);
+
+ ASSERT_TRUE(GC_is_disabled());
+
+ // pass control to main
+ writeString("bar", sink);
+ });
+
+ // pass control to coroutine
+ std::string foo = readString(*source);
+ ASSERT_EQ(foo, "foo");
+ ASSERT_FALSE(GC_is_disabled());
+ // pass control to coroutine
+ std::string bar = readString(*source);
+ ASSERT_EQ(bar, "bar");
+
+ ASSERT_FALSE(GC_is_disabled());
+ }
+#endif
+
+ // This test tests that boehm handles coroutine stacks correctly
+ // This test tests that coroutine stacks are registered to the GC,
+ // even when the coroutine is not running. It also tests that
+ // the main stack is still registered to the GC when the coroutine is running.
+ TEST(CoroGC, CoroutineStackNotGCd) {
+ initGC();
+
+ volatile void* do_collect = GC_MALLOC_ATOMIC(128);
+ volatile void* dont_collect = GC_MALLOC_ATOMIC(128);
+
+ bool* do_collect_witness = make_witness(do_collect);
+ bool* dont_collect_witness = make_witness(dont_collect);
+
+ do_collect = nullptr;
+
+ auto source = sinkToSource([&](Sink& sink) {
+ volatile void* dont_collect_inner = GC_MALLOC_ATOMIC(128);
+ volatile void* do_collect_inner = GC_MALLOC_ATOMIC(128);
+
+ bool* do_collect_inner_witness = make_witness(do_collect_inner);
+ bool* dont_collect_inner_witness = make_witness(dont_collect_inner);
+
+ do_collect_inner = nullptr;
+
+ // pass control to main
+ writeString("foo", sink);
+
+ ASSERT_FALSE(*dont_collect_inner_witness);
+ ASSERT_TRUE(*do_collect_inner_witness);
+ ASSERT_NE(nullptr, dont_collect_inner);
+
+ // pass control to main
+ writeString("bar", sink);
+ });
+
+ // pass control to coroutine
+ std::string foo = readString(*source);
+ ASSERT_EQ(foo, "foo");
+
+ ASSERT_FALSE(GC_is_disabled());
+ GC_gcollect();
+ GC_invoke_finalizers();
+
+ // pass control to coroutine
+ std::string bar = readString(*source);
+ ASSERT_EQ(bar, "bar");
+
+ ASSERT_FALSE(*dont_collect_witness);
+ ASSERT_TRUE(*do_collect_witness);
+ ASSERT_NE(nullptr, dont_collect);
+ }
+#endif
+}
diff --git a/src/libexpr/tests/local.mk b/src/libexpr/tests/local.mk
index 3e5504f71..c36d21bfe 100644
--- a/src/libexpr/tests/local.mk
+++ b/src/libexpr/tests/local.mk
@@ -16,4 +16,4 @@ libexpr-tests_CXXFLAGS += -I src/libexpr -I src/libutil -I src/libstore -I src/l
libexpr-tests_LIBS = libstore-tests libutils-tests libexpr libutil libstore libfetchers
-libexpr-tests_LDFLAGS := $(GTEST_LIBS) -lgmock
+libexpr-tests_LDFLAGS := $(GTEST_LIBS) -lgmock -lboost_context
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 7476e6f6c..6e53239f5 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -186,6 +186,22 @@ static DefaultStackAllocator defaultAllocatorSingleton;
StackAllocator *StackAllocator::defaultAllocator = &defaultAllocatorSingleton;
+std::shared_ptr<void> (*create_coro_gc_hook)() = []() -> std::shared_ptr<void> {
+ return {};
+};
+
+/* This class is used for entry and exit hooks on coroutines */
+class CoroutineContext {
+ /* Disable GC when entering the coroutine without the boehm patch,
+ * since it doesn't find the main thread stack in this case.
+ * std::shared_ptr<void> performs type-erasure, so it will call the right
+ * deleter. */
+ const std::shared_ptr<void> coro_gc_hook = create_coro_gc_hook();
+public:
+ CoroutineContext() {};
+ ~CoroutineContext() {};
+};
+
std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
{
struct SourceToSink : FinishSink
@@ -206,7 +222,8 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
if (in.empty()) return;
cur = in;
- if (!coro)
+ if (!coro) {
+ CoroutineContext ctx;
coro = coro_t::push_type(VirtualStackAllocator{}, [&](coro_t::pull_type & yield) {
LambdaSource source([&](char *out, size_t out_len) {
if (cur.empty()) {
@@ -223,17 +240,24 @@ std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
});
fun(source);
});
+ }
if (!*coro) { abort(); }
- if (!cur.empty()) (*coro)(false);
+ if (!cur.empty()) {
+ CoroutineContext ctx;
+ (*coro)(false);
+ }
}
void finish() override
{
if (!coro) return;
if (!*coro) abort();
- (*coro)(true);
+ {
+ CoroutineContext ctx;
+ (*coro)(true);
+ }
if (*coro) abort();
}
};
@@ -264,18 +288,23 @@ std::unique_ptr<Source> sinkToSource(
size_t read(char * data, size_t len) override
{
- if (!coro)
+ if (!coro) {
+ CoroutineContext ctx;
coro = coro_t::pull_type(VirtualStackAllocator{}, [&](coro_t::push_type & yield) {
LambdaSink sink([&](std::string_view data) {
if (!data.empty()) yield(std::string(data));
});
fun(sink);
});
+ }
if (!*coro) { eof(); abort(); }
if (pos == cur.size()) {
- if (!cur.empty()) (*coro)();
+ if (!cur.empty()) {
+ CoroutineContext ctx;
+ (*coro)();
+ }
cur = coro->get();
pos = 0;
}
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 7da5b07fd..e99c5fcc7 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -501,4 +501,10 @@ struct StackAllocator {
static StackAllocator *defaultAllocator;
};
+/* Disabling GC when entering a coroutine (without the boehm patch).
+ mutable to avoid boehm gc dependency in libutil.
+ */
+extern std::shared_ptr<void> (*create_coro_gc_hook)();
+
+
}