[Local GC] Enable building the GC as a shared library (#13137)

* [Local GC] Build the GC using system headers

* Disable features to get the GC to build

* Get rid of the separate 'GC PAL' build

* Remove unused stuff

* Don't build gcenv.os.cpp when linking in a standalone gc

* Stub out CPUGroupInfo and NumaNodeInfo

* Stub out IsGCThread and friends

* Build the GC as a shared library :tada:

* Build, link, and run! :tada:

* Fix standalone GC build break

* Fixes where the GC's MethodTable and VM's MethodTable classes disagree

* Integrate a standalone GC into the CoreCLR build system (so it gets copied to the output folder). Re-enable some ifdef-ed out includes that are required for a non-standalone build of the GC.

* Bring changes to Unix and fix the Unix build. Implement some compiler intrinsic wrappers and alignment functions expected by the GC.

* Fix the Windows build

* 1. Code review feedback: use standard types for BitScanForward and
   BitScanForward64
2. Delete FEATURE_COM stuff from the build system, not needed for this
PR
3. Fix the Unix build

* Fix the Windows x86 build - the _BitScanForward64 intrinsic is not available when targeting 32-bit platforms

* Remove a number of things from gcenv.base.h that are not used

* Remove a linker workaround now that we are not linking a standalone GC into the runtime

* Remove dead code, make the lack of GC_PROFILING for standalone gc not break profiling on the non-standalone build

* Code review feedback - use add_library_clr and other cmake-related fixes

* Fix include indentation

* Remove some extraneous parameters to cmake functions (cmake is remarkably lenient...)

1 files changed, 72 insertions, 0 deletions

diff --git a/src/gc/env/gcenv.h b/src/gc/env/gcenv.h
new file mode 100644
index 0000000000..c69f5f92fd
--- /dev/null
+++ b/src/gc/env/gcenv.h
@@ -0,0 +1,72 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#if defined(_DEBUG)
+#ifndef _DEBUG_IMPL
+#define _DEBUG_IMPL 1
+#endif
+#define ASSERT(_expr) assert(_expr)
+#else
+#define ASSERT(_expr)
+#endif
+
+#ifndef _ASSERTE
+#define _ASSERTE(_expr) ASSERT(_expr)
+#endif
+
+#include "gcenv.structs.h"
+#include "gcenv.base.h"
+#include "gcenv.os.h"
+#include "gcenv.interlocked.h"
+#include "gcenv.interlocked.inl"
+#include "gcenv.object.h"
+#include "gcenv.sync.h"
+#include "gcinterface.h"
+#include "gcenv.ee.h"
+
+#define MAX_LONGPATH 1024
+
+#ifdef _MSC_VER
+#define SUPPRESS_WARNING_4127   \
+    __pragma(warning(push))     \
+    __pragma(warning(disable:4127)) /* conditional expression is constant*/
+#define POP_WARNING_STATE       \
+    __pragma(warning(pop))
+#else // _MSC_VER
+#define SUPPRESS_WARNING_4127
+#define POP_WARNING_STATE
+#endif // _MSC_VER
+
+#define WHILE_0             \
+    SUPPRESS_WARNING_4127   \
+    while(0)                \
+    POP_WARNING_STATE       \
+
+#define LL_INFO10 4
+
+#define STRESS_LOG_VA(msg)                                              do { } WHILE_0
+#define STRESS_LOG0(facility, level, msg)                               do { } WHILE_0
+#define STRESS_LOG1(facility, level, msg, data1)                        do { } WHILE_0
+#define STRESS_LOG2(facility, level, msg, data1, data2)                 do { } WHILE_0
+#define STRESS_LOG3(facility, level, msg, data1, data2, data3)          do { } WHILE_0
+#define STRESS_LOG4(facility, level, msg, data1, data2, data3, data4)   do { } WHILE_0
+#define STRESS_LOG5(facility, level, msg, data1, data2, data3, data4, data5)   do { } WHILE_0
+#define STRESS_LOG6(facility, level, msg, data1, data2, data3, data4, data5, data6)   do { } WHILE_0
+#define STRESS_LOG7(facility, level, msg, data1, data2, data3, data4, data5, data6, data7)   do { } WHILE_0
+#define STRESS_LOG_PLUG_MOVE(plug_start, plug_end, plug_delta)          do { } WHILE_0
+#define STRESS_LOG_ROOT_PROMOTE(root_addr, objPtr, methodTable)         do { } WHILE_0
+#define STRESS_LOG_ROOT_RELOCATE(root_addr, old_value, new_value, methodTable) do { } WHILE_0
+#define STRESS_LOG_GC_START(gcCount, Gen, collectClasses)               do { } WHILE_0
+#define STRESS_LOG_GC_END(gcCount, Gen, collectClasses)                 do { } WHILE_0
+#define STRESS_LOG_OOM_STACK(size)   do { } while(0)
+#define STRESS_LOG_RESERVE_MEM(numChunks) do {} while (0)
+#define STRESS_LOG_GC_STACK
+
+#define LOG(x)
+
+#define SVAL_IMPL_INIT(type, cls, var, init) \
+    type cls::var = init
+
+#include "etmdummy.h"
+#define ETW_EVENT_ENABLED(e,f) false