[lldb][test] Set target and host OS for API tests in case of remote testing

Makefile.rules uses HOST_OS and OS variables for determining host and target
OSes for API tests compilation.

This commit starts moving the platform detection logic from Makefile to Python lldb
test suite.

When lldb's target is set to remote-linux, Makefile.rules script should be
executed with the target OS variable set to Linux.

This is useful for the case of Windows-to-Linux cross-testing.

Author: dzhidzhoev

lldb/packages/Python/lldbsuite/test/lldbplatformutil.py

@@ -92,11 +92,28 @@ def match_android_device(device_arch, valid_archs=None, valid_api_levels=None):
 
 
 def finalize_build_dictionary(dictionary):
+    # Provide uname-like platform name
+    platform_name_to_uname = {
+        "linux": "Linux",
+        "netbsd": "NetBSD",
+        "freebsd": "FreeBSD",
+        "windows": "Windows_NT",
+        "macosx": "Darwin",
+        "darwin": "Darwin",
+    }
+
+    if dictionary is None:
+        dictionary = {}
     if target_is_android():
-        if dictionary is None:
-            dictionary = {}
         dictionary["OS"] = "Android"
         dictionary["PIE"] = 1
+    elif platformIsDarwin():
+        dictionary["OS"] = "Darwin"
+    else:
+        dictionary["OS"] = platform_name_to_uname[getPlatform()]
+
+    dictionary["HOST_OS"] = platform_name_to_uname[getHostPlatform()]
+
     return dictionary
 
 
@@ -113,6 +130,10 @@ def _get_platform_os(p):
             platform = "openbsd"
         return platform
 
+    # Triple is not available if we're not connected yet
+    if p.GetName() == "remote-linux":
+        return "linux"
+
     return ""
 
 

lldb/packages/Python/lldbsuite/test/make/Makefile.rules

@@ -55,7 +55,10 @@ LLDB_BASE_DIR := $(THIS_FILE_DIR)/../../../../../
 # When running tests from Visual Studio, the environment variable isn't
 # inherited all the way down to the process spawned for make.
 #----------------------------------------------------------------------
-HOST_OS := $(shell uname -s)
+ifeq "$(HOST_OS)" ""
+  HOST_OS := $(shell uname -s)
+endif
+
 ifneq (,$(findstring windows32,$(HOST_OS)))
 	HOST_OS := Windows_NT
 endif