Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(464)

Unified Diff: src/ia32/full-codegen-ia32.cc

Issue 23526069: Refactor back edge table related code into a new class. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 7 years, 3 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « src/ia32/deoptimizer-ia32.cc ('k') | src/mips/deoptimizer-mips.cc » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index c9f7f32b6a2ec74ae81a14cd91017e1056c77742..9a2c3ce72c9dff731f7160aa9130a49472dba47a 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -4891,6 +4891,88 @@ FullCodeGenerator::NestedStatement* FullCodeGenerator::TryFinally::Exit(
#undef __
+
+static const byte kJnsInstruction = 0x79;
+static const byte kJnsOffset = 0x11;
+static const byte kCallInstruction = 0xe8;
+static const byte kNopByteOne = 0x66;
+static const byte kNopByteTwo = 0x90;
+
+// The back edge bookkeeping code matches the pattern:
+//
+// sub <profiling_counter>, <delta>
+// jns ok
+// call <interrupt stub>
+// ok:
+//
+// The patched back edge looks like this:
+//
+// sub <profiling_counter>, <delta> ;; Not changed
+// nop
+// nop
+// call <on-stack replacment>
+// ok:
+
+void BackEdgeTable::PatchAt(Code* unoptimized_code,
+ Address pc,
+ Code* replacement_code) {
+ // Turn the jump into nops.
+ Address call_target_address = pc - kIntSize;
+ *(call_target_address - 3) = kNopByteOne;
+ *(call_target_address - 2) = kNopByteTwo;
+ // Replace the call address.
+ Assembler::set_target_address_at(call_target_address,
+ replacement_code->entry());
+
+ unoptimized_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
+ unoptimized_code, call_target_address, replacement_code);
+}
+
+
+void BackEdgeTable::RevertAt(Code* unoptimized_code,
+ Address pc,
+ Code* interrupt_code) {
+ // Restore the original jump.
+ Address call_target_address = pc - kIntSize;
+ *(call_target_address - 3) = kJnsInstruction;
+ *(call_target_address - 2) = kJnsOffset;
+ // Restore the original call address.
+ Assembler::set_target_address_at(call_target_address,
+ interrupt_code->entry());
+
+ interrupt_code->GetHeap()->incremental_marking()->RecordCodeTargetPatch(
+ unoptimized_code, call_target_address, interrupt_code);
+}
+
+
+#ifdef DEBUG
+BackEdgeTable::BackEdgeState BackEdgeTable::GetBackEdgeState(
+ Isolate* isolate,
+ Code* unoptimized_code,
+ Address pc) {
+ Address call_target_address = pc - kIntSize;
+ ASSERT_EQ(kCallInstruction, *(call_target_address - 1));
+ if (*(call_target_address - 3) == kNopByteOne) {
+ ASSERT_EQ(kNopByteTwo, *(call_target_address - 2));
+ Code* osr_builtin =
+ isolate->builtins()->builtin(Builtins::kOnStackReplacement);
+ ASSERT_EQ(osr_builtin->entry(),
+ Assembler::target_address_at(call_target_address));
+ return ON_STACK_REPLACEMENT;
+ } else {
+ // Get the interrupt stub code object to match against from cache.
+ Code* interrupt_builtin =
+ isolate->builtins()->builtin(Builtins::kInterruptCheck);
+ ASSERT_EQ(interrupt_builtin->entry(),
+ Assembler::target_address_at(call_target_address));
+ ASSERT_EQ(kJnsInstruction, *(call_target_address - 3));
+ ASSERT_EQ(kJnsOffset, *(call_target_address - 2));
+ return INTERRUPT;
+ }
+}
+#endif // DEBUG
+
+
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_IA32
« no previous file with comments | « src/ia32/deoptimizer-ia32.cc ('k') | src/mips/deoptimizer-mips.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698