Added 32-bit version of nonsfi monacl shell

mojo/nacl/BUILD.gn

Index: mojo/nacl/BUILD.gn
diff --git a/mojo/nacl/BUILD.gn b/mojo/nacl/BUILD.gn
index 44e3b3e3d6ef7393b06f205882d49cbd8bce2ecd..b179087e84e20ee709cfdb6e5d7cd19e20244b4c 100644
--- a/mojo/nacl/BUILD.gn
+++ b/mojo/nacl/BUILD.gn
@@ -20,16 +20,34 @@ if (!is_nacl) {
     data_deps = [ "//nacl_bindings:irt_mojo(//native_client/build/toolchain/nacl:irt_${target_cpu})" ]
   }
 
-  executable("monacl_shell_nonsfi") {
-    testonly = true
-    sources = [
-      "monacl_shell_nonsfi.cc",
-    ]
-    deps = [
-      ":irt_mojo_nonsfi",
-      "//mojo/edk/system",
-      "//native_client/src/nonsfi/loader:elf_loader",
-    ]
+  if (current_cpu == "x86") {
+    # Non-SFI NaCl currently supports x86-32 but not x86-64. Additionally,
+    # PNaCl pexes assume 32-bit pointers.
+    executable("monacl_shell_nonsfi") {
+      testonly = true
+      sources = [
+        "monacl_shell_nonsfi.cc",
+      ]
+      deps = [
+        ":irt_mojo_nonsfi",
+        "//mojo/edk/system",
+        "//native_client/src/nonsfi/loader:elf_loader",
+      ]
+    }
+  }
+}
+
+group("monacl_shell_nonsfi_x86") {
+  testonly = true
+  deps = []
+  if ((target_cpu == "x64" || target_cpu == "x86") && is_linux) {
+    # Even when Mojo is built for x86-64 by default, we want to use x86-32
+    # for running programs under Non-SFI NaCl.
+    # The toolchain is hardcoded as 32-bit clang here -- although it must
+    # be 32 bit (for nonsfi), it assumes clang. Ideally, the toolchain would
+    # be defined as the 32 bit variant of whatever is being used (be it clang,
+    # gcc, or something else).
+    deps += [ ":monacl_shell_nonsfi(//build/toolchain/linux:clang_x86)" ]
   }
 }
 
@@ -104,6 +122,7 @@ group("mojo_nacl_tests") {
   deps = [
     ":mojo_nacl_tests_untrusted(//native_client/build/toolchain/nacl:clang_newlib_${current_cpu})",
     ":monacl_shell",
+    ":monacl_shell_nonsfi_x86",
     ":mojo_pnacl_tests",
   ]
 }