86 lines
4.6 KiB
Diff
86 lines
4.6 KiB
Diff
From 72853c670c97aae4eab64a5e9edb3c7176beaf6a Mon Sep 17 00:00:00 2001
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Date: Fri, 22 Jan 2021 16:36:41 +0800
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Subject: 8168926: C2: Bytecode escape analyzer crashes due to
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stack overflow
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Summary: <C2>:8168926: C2: Bytecode escape analyzer crashes due to stack overflow
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LLT: N/A
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Bug url: https://bugs.openjdk.java.net/browse/JDK-8168926
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---
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hotspot/src/share/vm/ci/bcEscapeAnalyzer.cpp | 30 ++++++++++++++++++--
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hotspot/src/share/vm/ci/ciMethod.hpp | 12 +++++---
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2 files changed, 35 insertions(+), 7 deletions(-)
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diff --git a/hotspot/src/share/vm/ci/bcEscapeAnalyzer.cpp b/hotspot/src/share/vm/ci/bcEscapeAnalyzer.cpp
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index 2b9e0e514..34bdbe94d 100644
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--- a/hotspot/src/share/vm/ci/bcEscapeAnalyzer.cpp
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+++ b/hotspot/src/share/vm/ci/bcEscapeAnalyzer.cpp
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@@ -894,9 +894,33 @@ void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, Growabl
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ciMethod* target = s.get_method(ignored_will_link, &declared_signature);
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ciKlass* holder = s.get_declared_method_holder();
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assert(declared_signature != NULL, "cannot be null");
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- // Push appendix argument, if one.
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- if (s.has_appendix()) {
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- state.apush(unknown_obj);
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+ // If the current bytecode has an attached appendix argument,
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+ // push an unknown object to represent that argument. (Analysis
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+ // of dynamic call sites, especially invokehandle calls, needs
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+ // the appendix argument on the stack, in addition to "regular" arguments
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+ // pushed onto the stack by bytecode instructions preceding the call.)
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+ //
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+ // The escape analyzer does _not_ use the ciBytecodeStream::has_appendix(s)
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+ // method to determine whether the current bytecode has an appendix argument.
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+ // The has_appendix() method obtains the appendix from the
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+ // ConstantPoolCacheEntry::_f1 field, which can happen concurrently with
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+ // resolution of dynamic call sites. Callees in the
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+ // ciBytecodeStream::get_method() call above also access the _f1 field;
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+ // interleaving the get_method() and has_appendix() calls in the current
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+ // method with call site resolution can lead to an inconsistent view of
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+ // the current method's argument count. In particular, some interleaving(s)
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+ // can cause the method's argument count to not include the appendix, which
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+ // then leads to stack over-/underflow in the escape analyzer.
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+ //
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+ // Instead of pushing the argument if has_appendix() is true, the escape analyzer
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+ // pushes an appendix for all call sites targeted by invokedynamic and invokehandle
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+ // instructions, except if the call site is the _invokeBasic intrinsic
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+ // (that intrinsic is always targeted by an invokehandle instruction but does
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+ // not have an appendix argument).
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+ if (target->is_loaded() &&
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+ Bytecodes::has_optional_appendix(s.cur_bc_raw()) &&
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+ target->intrinsic_id() != vmIntrinsics::_invokeBasic) {
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+ state.apush(unknown_obj);
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}
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// Pass in raw bytecode because we need to see invokehandle instructions.
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invoke(state, s.cur_bc_raw(), target, holder);
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diff --git a/hotspot/src/share/vm/ci/ciMethod.hpp b/hotspot/src/share/vm/ci/ciMethod.hpp
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index 307452422..99d8dbe67 100644
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--- a/hotspot/src/share/vm/ci/ciMethod.hpp
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+++ b/hotspot/src/share/vm/ci/ciMethod.hpp
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@@ -133,15 +133,19 @@ class ciMethod : public ciMetadata {
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check_is_loaded();
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return _signature->size() + (_flags.is_static() ? 0 : 1);
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}
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- // Report the number of elements on stack when invoking this method.
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- // This is different than the regular arg_size because invokedynamic
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- // has an implicit receiver.
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+ // Report the number of elements on stack when invoking the current method.
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+ // If the method is loaded, arg_size() gives precise information about the
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+ // number of stack elements (using the method's signature and its flags).
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+ // However, if the method is not loaded, the number of stack elements must
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+ // be determined differently, as the method's flags are not yet available.
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+ // The invoke_arg_size() method assumes in that case that all bytecodes except
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+ // invokestatic and invokedynamic have a receiver that is also pushed onto the
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+ // stack by the caller of the current method.
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int invoke_arg_size(Bytecodes::Code code) const {
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if (is_loaded()) {
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return arg_size();
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} else {
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int arg_size = _signature->size();
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- // Add a receiver argument, maybe:
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if (code != Bytecodes::_invokestatic &&
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code != Bytecodes::_invokedynamic) {
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arg_size++;
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--
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2.19.0
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