Revision: 6204
Author: [email protected]
Date: Thu Jan 6 05:48:12 2011
Log: Small change to stack checks in unoptimized code.
The stack checks include a loop nesting depth encoded in the code stream
after the call to the stack check stub. Change the code to jump around this
instruction as well as the call when the stack check is OK.
Review URL: http://codereview.chromium.org/6005014
http://code.google.com/p/v8/source/detail?r=6204
Modified:
/branches/bleeding_edge/src/arm/full-codegen-arm.cc
/branches/bleeding_edge/src/ia32/deoptimizer-ia32.cc
/branches/bleeding_edge/src/ia32/full-codegen-ia32.cc
/branches/bleeding_edge/src/x64/full-codegen-x64.cc
=======================================
--- /branches/bleeding_edge/src/arm/full-codegen-arm.cc Tue Jan 4 03:02:58
2011
+++ /branches/bleeding_edge/src/arm/full-codegen-arm.cc Thu Jan 6 05:48:12
2011
@@ -1,4 +1,4 @@
-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
@@ -221,10 +221,17 @@
__ b(hs, &ok);
StackCheckStub stub;
__ CallStub(&stub);
+ // Record a mapping of this PC offset to the OSR id. This is used to
find
+ // the AST id from the unoptimized code in order to use it as a key into
+ // the deoptimization input data found in the optimized code.
+ RecordStackCheck(stmt->OsrEntryId());
+
__ bind(&ok);
PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
+ // Record a mapping of the OSR id to this PC. This is used if the OSR
+ // entry becomes the target of a bailout. We don't expect it to be, but
+ // we want it to work if it is.
PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
- RecordStackCheck(stmt->OsrEntryId());
}
=======================================
--- /branches/bleeding_edge/src/ia32/deoptimizer-ia32.cc Tue Dec 7
03:53:19 2010
+++ /branches/bleeding_edge/src/ia32/deoptimizer-ia32.cc Thu Jan 6
05:48:12 2011
@@ -1,4 +1,4 @@
-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
@@ -105,23 +105,25 @@
void Deoptimizer::PatchStackCheckCode(RelocInfo* rinfo,
Code* replacement_code) {
- // The stack check code matches the pattern (on ia32, for example):
+ // The stack check code matches the pattern:
//
// cmp esp, <limit>
// jae ok
// call <stack guard>
+ // test eax, <loop nesting depth>
// ok: ...
//
- // We will patch the code to:
+ // We will patch away the branch so the code is:
//
// cmp esp, <limit> ;; Not changed
// nop
// nop
// call <on-stack replacment>
+ // test eax, <loop nesting depth>
// ok:
Address call_target_address = rinfo->pc();
ASSERT(*(call_target_address - 3) == 0x73 && // jae
- *(call_target_address - 2) == 0x05 && // offset
+ *(call_target_address - 2) == 0x07 && // offset
*(call_target_address - 1) == 0xe8); // call
*(call_target_address - 3) = 0x90; // nop
*(call_target_address - 2) = 0x90; // nop
@@ -130,12 +132,14 @@
void Deoptimizer::RevertStackCheckCode(RelocInfo* rinfo, Code* check_code)
{
+ // Replace the nops from patching (Deoptimizer::PatchStackCheckCode) to
+ // restore the conditional branch.
Address call_target_address = rinfo->pc();
ASSERT(*(call_target_address - 3) == 0x90 && // nop
*(call_target_address - 2) == 0x90 && // nop
*(call_target_address - 1) == 0xe8); // call
*(call_target_address - 3) = 0x73; // jae
- *(call_target_address - 2) = 0x05; // offset
+ *(call_target_address - 2) = 0x07; // offset
rinfo->set_target_address(check_code->entry());
}
=======================================
--- /branches/bleeding_edge/src/ia32/full-codegen-ia32.cc Thu Jan 6
05:29:22 2011
+++ /branches/bleeding_edge/src/ia32/full-codegen-ia32.cc Thu Jan 6
05:48:12 2011
@@ -264,16 +264,24 @@
__ j(above_equal, &ok, taken);
StackCheckStub stub;
__ CallStub(&stub);
- __ bind(&ok);
- PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
- PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
+ // Record a mapping of this PC offset to the OSR id. This is used to
find
+ // the AST id from the unoptimized code in order to use it as a key into
+ // the deoptimization input data found in the optimized code.
RecordStackCheck(stmt->OsrEntryId());
- // Loop stack checks can be patched to perform on-stack
- // replacement. In order to decide whether or not to perform OSR we
- // embed the loop depth in a test instruction after the call so we
- // can extract it from the OSR builtin.
+
+ // Loop stack checks can be patched to perform on-stack replacement. In
+ // order to decide whether or not to perform OSR we embed the loop depth
+ // in a test instruction after the call so we can extract it from the OSR
+ // builtin.
ASSERT(loop_depth() > 0);
__ test(eax, Immediate(Min(loop_depth(), Code::kMaxLoopNestingMarker)));
+
+ __ bind(&ok);
+ PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
+ // Record a mapping of the OSR id to this PC. This is used if the OSR
+ // entry becomes the target of a bailout. We don't expect it to be, but
+ // we want it to work if it is.
+ PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
}
=======================================
--- /branches/bleeding_edge/src/x64/full-codegen-x64.cc Thu Jan 6 05:29:22
2011
+++ /branches/bleeding_edge/src/x64/full-codegen-x64.cc Thu Jan 6 05:48:12
2011
@@ -210,10 +210,17 @@
__ j(above_equal, &ok);
StackCheckStub stub;
__ CallStub(&stub);
+ // Record a mapping of this PC offset to the OSR id. This is used to
find
+ // the AST id from the unoptimized code in order to use it as a key into
+ // the deoptimization input data found in the optimized code.
+ RecordStackCheck(stmt->OsrEntryId());
+
__ bind(&ok);
PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
+ // Record a mapping of the OSR id to this PC. This is used if the OSR
+ // entry becomes the target of a bailout. We don't expect it to be, but
+ // we want it to work if it is.
PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
- RecordStackCheck(stmt->OsrEntryId());
}
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