[v8-dev] Add flags to force or prevent setting of isolate.is_memory_constrained. (issue 23890027)

Fri, 13 Sep 2013 04:47:51 -0700 

Reviewers: Sven Panne, Hannes Payer,

Message:
As requested.  This enables both forcing and preventing of the
memory_constrained flag.  PTAL.

Description:
Add flags to force or prevent setting of isolate.is_memory_constrained.

Also, add a method of prohibiting illegal flag combinations.

BUG=None.

Please review this at https://codereview.chromium.org/23890027/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files (+39, -2 lines):
  M src/api.cc
  M src/flag-definitions.h
  M src/flags.h
  M src/flags.cc
  M src/isolate.cc
  M src/v8.cc


Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index d1f6b78cc0c1d06b0d252071d8bf6c0a2573d5ee..8ef7e5fdc65ef19c8e2d81e0746873975b8a4905 100644 
--- a/src/api.cc
+++ b/src/api.cc
@@ -647,7 +647,9 @@ bool SetResourceConstraints(ResourceConstraints* constraints) { uintptr_t limit = reinterpret_cast<uintptr_t>(constraints->stack_limit()); 
     isolate->stack_guard()->SetStackLimit(limit);
   }
-  if (constraints->is_memory_constrained().has_value) {
+  if (constraints->is_memory_constrained().has_value &&
+      !i::FLAG_force_memory_constrained &&
+      !i::FLAG_prevent_memory_constrained) {
     isolate->set_is_memory_constrained(
         constraints->is_memory_constrained().value);
   }
Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 7548c01643615a0a9b293389dc4c6206120d91f2..b894d2b14201e09604773febc6f3f586e14df6b5 100644 
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -69,6 +69,17 @@
 #define DEFINE_implication(whenflag, thenflag) \
   if (FLAG_##whenflag) FLAG_##thenflag = true;

+// We produce the code to un-set restricted flags when it is prohibited by
+// another flag.
+#elif defined(FLAG_MODE_DEFINE_RESTRICTIONS)
+#define DEFINE_prohibited(whenflag, preventflag) \ + if (FLAG_##whenflag && FLAG_##preventflag) { \ + PrintF(stderr, \ + "Warning: cannot set both --"#whenflag" and "#preventflag".\n" \ + " Unsetting --"#preventflag".\n" ); \ + FLAG_##preventflag = !FLAG_##whenflag; \ 
+  }
+
 #else
 #error No mode supplied when including flags.defs
 #endif
@@ -90,6 +101,10 @@
 #define DEFINE_implication(whenflag, thenflag)
 #endif

+#ifndef DEFINE_prohibited
+#define DEFINE_prohibited(whenflag, preventflag)
+#endif
+

 #ifdef FLAG_MODE_DECLARE
 // Structure used to hold a collection of arguments to the JavaScript code.
@@ -601,6 +616,11 @@ DEFINE_int(hash_seed,
            0,
            "Fixed seed to use to hash property keys (0 means random)"
"(with snapshots this option cannot override the baked-in seed)") 
+DEFINE_bool(force_memory_constrained, false,
+            "force the runtime to treat the device as memory constrained.")
+DEFINE_bool(prevent_memory_constrained, false,
+ "prevent the runtime to treat the device as memory constrained.") 
+DEFINE_prohibited(force_memory_constrained, prevent_memory_constrained)

 // v8.cc
 DEFINE_bool(preemption, false,
@@ -840,6 +860,7 @@ DEFINE_implication(print_all_code, trace_codegen)
 #undef DEFINE_float
 #undef DEFINE_args
 #undef DEFINE_implication
+#undef DEFINE_prohibited
 #undef DEFINE_ALIAS_bool
 #undef DEFINE_ALIAS_int
 #undef DEFINE_ALIAS_string
@@ -851,3 +872,4 @@ DEFINE_implication(print_all_code, trace_codegen)
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
+#undef FLAG_MODE_DEFINE_RESTRICTIONS
Index: src/flags.cc
diff --git a/src/flags.cc b/src/flags.cc
index 4e18cc8c80832b5b1217424acecfa9e9c3578190..6c391751d7c6ad916947779a19436360a91a55f8 100644 
--- a/src/flags.cc
+++ b/src/flags.cc
@@ -549,10 +549,19 @@ void FlagList::PrintHelp() {
 }


+// static
 void FlagList::EnforceFlagImplications() {
 #define FLAG_MODE_DEFINE_IMPLICATIONS
 #include "flag-definitions.h"
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 }

+
+// static
+void FlagList::EnforceFlagRestrictions() {
+#define FLAG_MODE_DEFINE_RESTRICTIONS
+#include "flag-definitions.h"
+#undef FLAG_MODE_DEFINE_RESTRICTIONS
+}
+
 } }  // namespace v8::internal
Index: src/flags.h
diff --git a/src/flags.h b/src/flags.h
index fe182e5221cec755e4c629ffabda040e738e701a..b5dc6a2a46568f0a63907dbe7b3fc2e718e59e6e 100644 
--- a/src/flags.h
+++ b/src/flags.h
@@ -78,6 +78,9 @@ class FlagList {

   // Set flags as consequence of being implied by another flag.
   static void EnforceFlagImplications();
+
+  // Unset flags as a consequnce of illegal flag combinations.
+  static void EnforceFlagRestrictions();
 };

 } }  // namespace v8::internal
Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 8e581359dca1393b38efa29ab3f13d3ffce9399c..05d3fbfc3998f670e8bfacbb1774d43a43d0840e 100644 
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1776,7 +1776,7 @@ Isolate::Isolate()
       // TODO(bmeurer) Initialized lazily because it depends on flags; can
       // be fixed once the default isolate cleanup is done.
       random_number_generator_(NULL),
-      is_memory_constrained_(false),
+      is_memory_constrained_(FLAG_force_memory_constrained),
       has_fatal_error_(false),
       use_crankshaft_(true),
       initialized_from_snapshot_(false),
Index: src/v8.cc
diff --git a/src/v8.cc b/src/v8.cc
index e894164cd16207448befdc3c0daa93bf08c315bc..ded19b1edf49549d68804ede996bd182a0556d03 100644 
--- a/src/v8.cc
+++ b/src/v8.cc
@@ -197,6 +197,7 @@ Object* V8::FillHeapNumberWithRandom(Object* heap_number, 

 void V8::InitializeOncePerProcessImpl() {
   FlagList::EnforceFlagImplications();
+  FlagList::EnforceFlagRestrictions();
   if (FLAG_stress_compaction) {
     FLAG_force_marking_deque_overflows = true;
     FLAG_gc_global = true;


--
--
v8-dev mailing list
v8-dev@googlegroups.com
http://groups.google.com/group/v8-dev
--- You received this message because you are subscribed to the Google Groups "v8-dev" group. 
To unsubscribe from this group and stop receiving emails from it, send an email 
to v8-dev+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

Reply via email to