28 lines
733 B
Markdown
28 lines
733 B
Markdown
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0. Define how many physical regs are available, which are caller-saved and callee-saved
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1. Implement if-else and while statements
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2. Find out what use[B] and def[B] are for each block
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3. Define successors and predecessors of each block and make them accessible
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4. Compute liveIn[B] and liveOut[B] for each block
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Classic equations:
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liveIn[B] = use[B] ∪ (liveOut[B] - def[B])
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liveOut[B] = ⋃ liveIn[S] for S in succ[B]
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5. Linear scan register allocation
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- Instruction numbering + per-instruction liveness
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- Live intervals
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- Linear scan allocator with ~6 fake regs
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- Spill to stack slots
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- Add “CALL clobbers regs” rule
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function's reserved registers:
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EAX, ECX, EDX
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return registers:
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int => EAX
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float => ST0 |