move conditions for JIT into SkVM.h

This makes it easier to keep in sync with the implementation in
SkVM.cpp, and it's easier to handle here once than in each build system.

Change-Id: I429f90cfc16f35a0d7e0b0fde176bc013aa7db18
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/310263
Commit-Queue: Mike Klein <[email protected]>
Commit-Queue: Herb Derby <[email protected]>
Auto-Submit: Mike Klein <[email protected]>
Reviewed-by: Herb Derby <[email protected]>

Author: Mike Klein

BUILD.gn

@@ -1016,8 +1016,8 @@ optional("sksl_interpreter") {
 }
 
 optional("skvm_jit") {
-  enabled = skia_enable_skvm_jit
-  public_defines = [ "SKVM_JIT" ]
+  enabled = skia_enable_skvm_jit_when_possible
+  public_defines = [ "SKVM_JIT_WHEN_POSSIBLE" ]
   if (skia_vtune_path != "") {
     public_defines += [ "SKVM_JIT_VTUNE" ]
     public_include_dirs = [ "$skia_vtune_path/include" ]

gn/skia.gni

@@ -25,10 +25,7 @@ declare_args() {
   skia_enable_skottie = !(is_win && is_component_build)
   skia_enable_skrive = true
   skia_enable_sksl_interpreter = is_skia_dev_build
-  skia_enable_skvm_jit =
-      is_skia_dev_build &&
-      ((target_cpu == "x64" && (is_linux || is_mac || is_win)) ||
-       (target_cpu == "arm64" && is_android))
+  skia_enable_skvm_jit_when_possible = is_skia_dev_build
   skia_enable_tools = is_skia_dev_build
   skia_enable_gpu_debug_layers = is_skia_dev_build && is_debug
   skia_generate_workarounds = false

src/core/SkVM.h

@@ -19,6 +19,19 @@
 
 class SkWStream;
 
+#if defined(SKVM_JIT_WHEN_POSSIBLE)
+    #if defined(__x86_64__) || defined(_M_X64)
+        #if defined(_WIN32) || defined(__linux) || defined(__APPLE__)
+            #define SKVM_JIT
+        #endif
+    #endif
+    #if defined(__aarch64__)
+        #if defined(__ANDROID__)
+            #define SKVM_JIT
+        #endif
+    #endif
+#endif
+
 #if 0
     #define SKVM_LLVM
 #endif