Vyacheslav Egorov
ee0f608ce4
This version is Clang/GCC only and does not support Windows because it uses computed goto's. Only unoptimized mode is supported. Architecture is described in constants_dbc.h and stack_frame_dbc.h. R=fschneider@google.com, zra@google.com Review URL: https://codereview.chromium.org/1858283002 .
86 lines
3.2 KiB
C++
86 lines
3.2 KiB
C++
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_STACK_FRAME_DBC_H_
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#define VM_STACK_FRAME_DBC_H_
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namespace dart {
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/* DBC Frame Layout
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IMPORTANT: On DBC stack is growing upwards which is different from all other
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architectures. This enables effecient addressing for locals via unsigned index.
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| | <- TOS
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Callee frame | ... |
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| saved FP | (FP of current frame)
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| saved PC | (PC of current frame)
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| code object |
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| function object |
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+--------------------+
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Current frame | ... T| <- SP of current frame
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| ... T|
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| first local T| <- FP of current frame
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| caller's FP *|
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| caller's PC *|
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| code object T| (current frame's code object)
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| function object T| (current frame's function object)
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+--------------------+
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Caller frame | last parameter | <- SP of caller frame
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| ... |
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T against a slot indicates it needs to be traversed during GC.
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* against a slot indicates that it can be traversed during GC
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because it will look like a smi to the visitor.
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*/
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static const int kDartFrameFixedSize = 4; // Function, Code, PC, FP
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static const int kSavedPcSlotFromSp = 3;
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static const int kFirstObjectSlotFromFp = -4; // Used by GC to traverse stack.
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static const int kSavedCallerFpSlotFromFp = -1;
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static const int kSavedCallerPpSlotFromFp = kSavedCallerFpSlotFromFp;
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static const int kSavedCallerPcSlotFromFp = -2;
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static const int kCallerSpSlotFromFp = -kDartFrameFixedSize-1;
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static const int kPcMarkerSlotFromFp = -3;
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static const int kFunctionSlotFromFp = -4;
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// Note: These constants don't match actual DBC behavior. This is done because
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// setting kFirstLocalSlotFromFp to 0 breaks assumptions spread across the code.
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// Instead for the purposes of local variable allocation we pretend that DBC
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// behaves as other architectures (stack growing downwards) and later fix
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// these indices during code generation in the backend.
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static const int kParamEndSlotFromFp = 4; // One slot past last parameter.
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static const int kFirstLocalSlotFromFp = -1;
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DART_FORCE_INLINE static uword LocalVarAddress(uword fp, intptr_t index) {
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ASSERT(index != 0);
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if (index > 0) {
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return fp - index * kWordSize;
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} else {
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return fp - (index + 1) * kWordSize;
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}
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}
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DART_FORCE_INLINE static uword ParamAddress(uword fp, intptr_t reverse_index) {
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return fp - (kDartFrameFixedSize + reverse_index) * kWordSize;
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}
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DART_FORCE_INLINE static bool IsCalleeFrameOf(uword fp, uword other_fp) {
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return other_fp > fp;
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}
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static const int kExitLinkSlotFromEntryFp = 0;
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// Value for stack limit that is used to cause an interrupt.
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// Note that on DBC stack is growing upwards so interrupt limit is 0 unlike
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// on all other architectures.
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static const uword kInterruptStackLimit = 0;
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} // namespace dart
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#endif // VM_STACK_FRAME_DBC_H_
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