Martin Kustermann
a603635b85
So far the frontend (parser, flow graph builder, ssa construction) were aware of the actual frame layout. This CL makes the indices we assign to [LocalVariable]s logical indices, assigning: * M parameters the indices 1 ... M * N local variables the indices 0 -1 ... -(N-1) The scope building, flow graph builder and ssa construction operate on those logical indices. When emitting actual code, the backend will translate those indices into actual FP relative indices. This allows us to be more flexible in the backend which frame layout we choose. Issue https://github.com/dart-lang/sdk/issues/33274 Change-Id: I9a504bf97821c257aafd2b3430df9f4c9da4b442 Reviewed-on: https://dart-review.googlesource.com/57321 Commit-Queue: Martin Kustermann <kustermann@google.com> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
86 lines
3.4 KiB
C++
86 lines
3.4 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 RUNTIME_VM_STACK_FRAME_DBC_H_
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#define RUNTIME_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 efficient 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 kLastFixedObjectSlotFromFp = -3;
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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 intptr_t LocalVarIndex(intptr_t fp_offset,
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intptr_t var_index) {
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if (var_index > 0) {
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return fp_offset - var_index;
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} else {
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return fp_offset - (var_index + 1);
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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 // RUNTIME_VM_STACK_FRAME_DBC_H_
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