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// Copyright 2008 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:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#if defined(V8_TARGET_ARCH_ARM)
#include "codegen-inl.h"
#include "jump-target-inl.h"
#include "register-allocator-inl.h"
#include "virtual-frame-inl.h"
namespace v8 {
namespace internal {
// -------------------------------------------------------------------------
// JumpTarget implementation.
#define __ ACCESS_MASM(cgen()->masm())
void JumpTarget::DoJump() {
ASSERT(cgen()->has_valid_frame());
// Live non-frame registers are not allowed at unconditional jumps
// because we have no way of invalidating the corresponding results
// which are still live in the C++ code.
ASSERT(cgen()->HasValidEntryRegisters());
if (entry_frame_set_) {
if (entry_label_.is_bound()) {
// If we already bound and generated code at the destination then it
// is too late to ask for less optimistic type assumptions.
ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
}
// There already a frame expectation at the target.
cgen()->frame()->MergeTo(&entry_frame_);
cgen()->DeleteFrame();
} else {
// Clone the current frame to use as the expected one at the target.
set_entry_frame(cgen()->frame());
// Zap the fall-through frame since the jump was unconditional.
RegisterFile empty;
cgen()->SetFrame(NULL, &empty);
}
if (entry_label_.is_bound()) {
// You can't jump backwards to an already bound label unless you admitted
// up front that this was a bidirectional jump target. Bidirectional jump
// targets will zap their type info when bound in case some later virtual
// frame with less precise type info branches to them.
ASSERT(direction_ != FORWARD_ONLY);
}
__ jmp(&entry_label_);
}
void JumpTarget::DoBranch(Condition cond, Hint ignored) {
ASSERT(cgen()->has_valid_frame());
if (entry_frame_set_) {
if (entry_label_.is_bound()) {
// If we already bound and generated code at the destination then it
// is too late to ask for less optimistic type assumptions.
ASSERT(entry_frame_.IsCompatibleWith(cgen()->frame()));
}
// We have an expected frame to merge to on the backward edge.
cgen()->frame()->MergeTo(&entry_frame_, cond);
} else {
// Clone the current frame to use as the expected one at the target.
set_entry_frame(cgen()->frame());
}
if (entry_label_.is_bound()) {
// You can't branch backwards to an already bound label unless you admitted
// up front that this was a bidirectional jump target. Bidirectional jump
// targets will zap their type info when bound in case some later virtual
// frame with less precise type info branches to them.
ASSERT(direction_ != FORWARD_ONLY);
}
__ b(cond, &entry_label_);
if (cond == al) {
cgen()->DeleteFrame();
}
}
void JumpTarget::Call() {
// Call is used to push the address of the catch block on the stack as
// a return address when compiling try/catch and try/finally. We
// fully spill the frame before making the call. The expected frame
// at the label (which should be the only one) is the spilled current
// frame plus an in-memory return address. The "fall-through" frame
// at the return site is the spilled current frame.
ASSERT(cgen()->has_valid_frame());
// There are no non-frame references across the call.
ASSERT(cgen()->HasValidEntryRegisters());
ASSERT(!is_linked());
// Calls are always 'forward' so we use a copy of the current frame (plus
// one for a return address) as the expected frame.
ASSERT(!entry_frame_set_);
VirtualFrame target_frame = *cgen()->frame();
target_frame.Adjust(1);
set_entry_frame(&target_frame);
__ bl(&entry_label_);
}
void JumpTarget::DoBind() {
ASSERT(!is_bound());
// Live non-frame registers are not allowed at the start of a basic
// block.
ASSERT(!cgen()->has_valid_frame() || cgen()->HasValidEntryRegisters());
if (cgen()->has_valid_frame()) {
if (direction_ != FORWARD_ONLY) cgen()->frame()->ForgetTypeInfo();
// If there is a current frame we can use it on the fall through.
if (!entry_frame_set_) {
entry_frame_ = *cgen()->frame();
entry_frame_set_ = true;
} else {
cgen()->frame()->MergeTo(&entry_frame_);
// On fall through we may have to merge both ways.
if (direction_ != FORWARD_ONLY) {
// This will not need to adjust the virtual frame entries that are
// register allocated since that was done above and they now match.
// But it does need to adjust the entry_frame_ of this jump target
// to make it potentially less optimistic. Later code can branch back
// to this jump target and we need to assert that that code does not
// have weaker assumptions about types.
entry_frame_.MergeTo(cgen()->frame());
}
}
} else {
// If there is no current frame we must have an entry frame which we can
// copy.
ASSERT(entry_frame_set_);
RegisterFile empty;
cgen()->SetFrame(new VirtualFrame(&entry_frame_), &empty);
}
__ bind(&entry_label_);
}
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM