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https://github.com/golang/go
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[dev.ssa] cmd/internal/ssa: Add register allocation
Add a simple register allocator. It does only intra-basicblock allocation. It uses a greedy one-pass allocation treating the register file as a cache. Change-Id: Ib6b52f48270e08dfda98f2dd842b05afc3ab01ce Reviewed-on: https://go-review.googlesource.com/9761 Reviewed-by: Alan Donovan <adonovan@google.com>
This commit is contained in:
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@ -19,7 +19,7 @@ type Block struct {
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Kind BlockKind
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// Subsequent blocks, if any. The number and order depend on the block kind.
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// All blocks must be distinct (to make phi values in successors unambiguous).
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// All successors must be distinct (to make phi values in successors unambiguous).
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Succs []*Block
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// Inverse of successors.
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@ -33,8 +33,9 @@ type Block struct {
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// has a memory control value.
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Control *Value
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// The unordered set of Values contained in this block.
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// The unordered set of Values that define the operation of this block.
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// The list must include the control value, if any. (TODO: need this last condition?)
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// After the scheduling pass, this list is ordered.
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Values []*Value
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// The containing function
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@ -18,9 +18,6 @@ func cgen(f *Func) {
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// TODO: prolog, allocate stack frame
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// hack for now, until regalloc is done
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f.RegAlloc = make([]Location, f.NumValues())
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for idx, b := range f.Blocks {
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fmt.Printf("%d:\n", b.ID)
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for _, v := range b.Values {
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@ -63,8 +63,8 @@ var passes = [...]pass{
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{"critical", critical}, // remove critical edges
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{"layout", layout}, // schedule blocks
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{"schedule", schedule}, // schedule values
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// regalloc
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// stack slot alloc (+size stack frame)
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{"regalloc", regalloc},
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{"stackalloc", stackalloc},
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{"cgen", cgen},
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}
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@ -72,19 +72,26 @@ var passes = [...]pass{
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// This code is intended to document the ordering requirements
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// between different phases. It does not override the passes
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// list above.
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var passOrder = map[string]string{
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type constraint struct {
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a, b string // a must come before b
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}
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var passOrder = [...]constraint{
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// don't layout blocks until critical edges have been removed
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"critical": "layout",
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{"critical", "layout"},
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// regalloc requires the removal of all critical edges
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//"critical": "regalloc",
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{"critical", "regalloc"},
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// regalloc requires all the values in a block to be scheduled
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//"schedule": "regalloc",
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// code generation requires register allocation
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//"regalloc": "cgen",
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{"schedule", "regalloc"},
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// stack allocation requires register allocation
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{"regalloc", "stackalloc"},
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// code generation requires stack allocation
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{"stackalloc", "cgen"},
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}
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func init() {
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for a, b := range passOrder {
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for _, c := range passOrder {
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a, b := c.a, c.b
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i := -1
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j := -1
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for k, p := range passes {
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@ -29,7 +29,7 @@ func critical(f *Func) {
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// split input edges coming from multi-output blocks.
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for i, c := range b.Preds {
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if c.Kind == BlockPlain {
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continue
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continue // only single output block
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}
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// allocate a new block to place on the edge
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@ -28,7 +28,7 @@ type LocalSlot struct {
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}
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func (s *LocalSlot) Name() string {
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return fmt.Sprintf("loc%d", s.idx)
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return fmt.Sprintf("-%d(FP)", s.idx)
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}
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// An ArgSlot is a location in the parents' stack frame where it passed us an argument.
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@ -127,6 +127,9 @@ const (
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OpMOVQstoreFP
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OpMOVQstoreSP
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// materialize a constant into a register
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OpMOVQconst
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OpMax // sentinel
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)
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@ -151,14 +154,13 @@ type regMask uint64
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var regs386 = [...]string{
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"AX",
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"BX",
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"CX",
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"DX",
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"SI",
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"DI",
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"BX",
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"SP",
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"BP",
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"X0",
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"SI",
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"DI",
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// pseudo registers
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"FLAGS",
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@ -166,10 +168,10 @@ var regs386 = [...]string{
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}
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// TODO: match up these with regs386 above
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var gp regMask = 0xff
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var cx regMask = 0x4
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var flags regMask = 1 << 9
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var overwrite0 regMask = 1 << 10
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var gp regMask = 0xef
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var cx regMask = 0x2
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var flags regMask = 1 << 8
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var overwrite0 regMask = 1 << 9
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const (
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// possible properties of opcodes
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@ -177,20 +179,23 @@ const (
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// architecture constants
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Arch386
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ArchAmd64
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ArchArm
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ArchAMD64
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ArchARM
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)
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// general purpose registers, 2 input, 1 output
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var gp21 = [2][]regMask{{gp, gp}, {gp}}
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var gp21_overwrite = [2][]regMask{{gp, gp}, {overwrite0}}
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var gp21_overwrite = [2][]regMask{{gp, gp}, {gp}}
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// general purpose registers, 1 input, 1 output
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var gp11 = [2][]regMask{{gp}, {gp}}
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var gp11_overwrite = [2][]regMask{{gp}, {overwrite0}}
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var gp11_overwrite = [2][]regMask{{gp}, {gp}}
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// general purpose registers, 0 input, 1 output
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var gp01 = [2][]regMask{{}, {gp}}
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// shift operations
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var shift = [2][]regMask{{gp, cx}, {overwrite0}}
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var shift = [2][]regMask{{gp, cx}, {gp}}
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var gp2_flags = [2][]regMask{{gp, gp}, {flags}}
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var gp1_flags = [2][]regMask{{gp}, {flags}}
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@ -199,6 +204,9 @@ var gploadX = [2][]regMask{{gp, gp, 0}, {gp}} // indexed loads
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var gpstore = [2][]regMask{{gp, gp, 0}, {0}}
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var gpstoreX = [2][]regMask{{gp, gp, gp, 0}, {0}} // indexed stores
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var gpload_stack = [2][]regMask{{0}, {gp}}
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var gpstore_stack = [2][]regMask{{gp, 0}, {0}}
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// Opcodes that represent the input Go program
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var genericTable = [...]OpInfo{
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// the unknown op is used only during building and should not appear in a
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@ -284,6 +292,8 @@ var amd64Table = [...]OpInfo{
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OpMOVQload8: {asm: "MOVQ\t%A(%I0)(%I1*8),%O0", reg: gploadX},
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OpMOVQstore8: {asm: "MOVQ\t%I2,%A(%I0)(%I1*8)", reg: gpstoreX},
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OpMOVQconst: {asm: "MOVQ\t$%A,%O0", reg: gp01},
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OpStaticCall: {asm: "CALL\t%A(SB)"},
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OpCopy: {asm: "MOVQ\t%I0,%O0", reg: gp11},
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@ -292,17 +302,17 @@ var amd64Table = [...]OpInfo{
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OpSETL: {},
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// ops for load/store to stack
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OpMOVQloadFP: {asm: "MOVQ\t%A(FP),%O0"},
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OpMOVQloadSP: {asm: "MOVQ\t%A(SP),%O0"},
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OpMOVQstoreFP: {asm: "MOVQ\t%I0,%A(FP)"},
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OpMOVQstoreSP: {asm: "MOVQ\t%I0,%A(SP)"},
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OpMOVQloadFP: {asm: "MOVQ\t%A(FP),%O0", reg: gpload_stack}, // mem -> value
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OpMOVQloadSP: {asm: "MOVQ\t%A(SP),%O0", reg: gpload_stack}, // mem -> value
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OpMOVQstoreFP: {asm: "MOVQ\t%I0,%A(FP)", reg: gpstore_stack}, // mem, value -> mem
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OpMOVQstoreSP: {asm: "MOVQ\t%I0,%A(SP)", reg: gpstore_stack}, // mem, value -> mem
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// ops for spilling of registers
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// unlike regular loads & stores, these take no memory argument.
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// They are just like OpCopy but we use them during register allocation.
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// TODO: different widths, float
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OpLoadReg8: {asm: "MOVQ\t%I0,%O0", reg: gp11},
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OpStoreReg8: {asm: "MOVQ\t%I0,%O0", reg: gp11},
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OpLoadReg8: {asm: "MOVQ\t%I0,%O0"},
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OpStoreReg8: {asm: "MOVQ\t%I0,%O0"},
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}
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// A Table is a list of opcodes with a common set of flags.
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@ -313,7 +323,7 @@ type Table struct {
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var tables = []Table{
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{genericTable[:], 0},
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{amd64Table[:], ArchAmd64}, // TODO: pick this dynamically
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{amd64Table[:], ArchAMD64}, // TODO: pick this dynamically
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}
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// table of opcodes, indexed by opcode ID
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@ -4,9 +4,9 @@ package ssa
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import "fmt"
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const _Op_name = "OpUnknownOpNopOpFwdRefOpAddOpSubOpMulOpLessOpConstOpArgOpGlobalOpFuncOpCopyOpPhiOpSliceMakeOpSlicePtrOpSliceLenOpSliceCapOpStringMakeOpStringPtrOpStringLenOpSliceIndexOpSliceIndexAddrOpLoadOpStoreOpCheckNilOpCheckBoundOpCallOpStaticCallOpConvertOpConvNopOpFPAddrOpSPAddrOpStoreReg8OpLoadReg8OpADDQOpSUBQOpADDCQOpSUBCQOpMULQOpMULCQOpSHLQOpSHLCQOpNEGQOpCMPQOpCMPCQOpADDLOpTESTQOpSETEQOpSETNEOpSETLOpSETGEOpSETBOpInvertFlagsOpLEAQOpLEAQ2OpLEAQ4OpLEAQ8OpMOVQloadOpMOVQstoreOpMOVQload8OpMOVQstore8OpMOVQloadFPOpMOVQloadSPOpMOVQstoreFPOpMOVQstoreSPOpMax"
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const _Op_name = "OpUnknownOpNopOpFwdRefOpAddOpSubOpMulOpLessOpConstOpArgOpGlobalOpFuncOpCopyOpPhiOpSliceMakeOpSlicePtrOpSliceLenOpSliceCapOpStringMakeOpStringPtrOpStringLenOpSliceIndexOpSliceIndexAddrOpLoadOpStoreOpCheckNilOpCheckBoundOpCallOpStaticCallOpConvertOpConvNopOpFPAddrOpSPAddrOpStoreReg8OpLoadReg8OpADDQOpSUBQOpADDCQOpSUBCQOpMULQOpMULCQOpSHLQOpSHLCQOpNEGQOpCMPQOpCMPCQOpADDLOpTESTQOpSETEQOpSETNEOpSETLOpSETGEOpSETBOpInvertFlagsOpLEAQOpLEAQ2OpLEAQ4OpLEAQ8OpMOVQloadOpMOVQstoreOpMOVQload8OpMOVQstore8OpMOVQloadFPOpMOVQloadSPOpMOVQstoreFPOpMOVQstoreSPOpMOVQconstOpMax"
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var _Op_index = [...]uint16{0, 9, 14, 22, 27, 32, 37, 43, 50, 55, 63, 69, 75, 80, 91, 101, 111, 121, 133, 144, 155, 167, 183, 189, 196, 206, 218, 224, 236, 245, 254, 262, 270, 281, 291, 297, 303, 310, 317, 323, 330, 336, 343, 349, 355, 362, 368, 375, 382, 389, 395, 402, 408, 421, 427, 434, 441, 448, 458, 469, 480, 492, 504, 516, 529, 542, 547}
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var _Op_index = [...]uint16{0, 9, 14, 22, 27, 32, 37, 43, 50, 55, 63, 69, 75, 80, 91, 101, 111, 121, 133, 144, 155, 167, 183, 189, 196, 206, 218, 224, 236, 245, 254, 262, 270, 281, 291, 297, 303, 310, 317, 323, 330, 336, 343, 349, 355, 362, 368, 375, 382, 389, 395, 402, 408, 421, 427, 434, 441, 448, 458, 469, 480, 492, 504, 516, 529, 542, 553, 558}
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func (i Op) String() string {
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if i < 0 || i+1 >= Op(len(_Op_index)) {
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421
src/cmd/internal/ssa/regalloc.go
Normal file
421
src/cmd/internal/ssa/regalloc.go
Normal file
@ -0,0 +1,421 @@
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package ssa
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import (
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"fmt"
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"log"
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"sort"
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)
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func setloc(home []Location, v *Value, loc Location) []Location {
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for v.ID >= ID(len(home)) {
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home = append(home, nil)
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}
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home[v.ID] = loc
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return home
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}
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type register uint
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// TODO: make arch-dependent
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var numRegs register = 32
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var registers = [...]Register{
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Register{"AX"},
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Register{"CX"},
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Register{"DX"},
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Register{"BX"},
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Register{"SP"},
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Register{"BP"},
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Register{"SI"},
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Register{"DI"},
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// TODO R8, X0, ...
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// TODO: make arch-dependent
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Register{"FLAGS"},
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Register{"OVERWRITE"},
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}
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// countRegs returns the number of set bits in the register mask.
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func countRegs(r regMask) int {
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n := 0
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for r != 0 {
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n += int(r & 1)
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r >>= 1
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}
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return n
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}
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// pickReg picks an arbitrary register from the register mask.
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func pickReg(r regMask) register {
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// pick the lowest one
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if r == 0 {
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panic("can't pick a register from an empty set")
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}
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for i := register(0); ; i++ {
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if r&1 != 0 {
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return i
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}
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r >>= 1
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}
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}
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// regalloc performs register allocation on f. It sets f.RegAlloc
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// to the resulting allocation.
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func regalloc(f *Func) {
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// For now, a very simple allocator. Everything has a home
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// location on the stack (TBD as a subsequent stackalloc pass).
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// Values live in the home locations at basic block boundaries.
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// We use a simple greedy allocator within a basic block.
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home := make([]Location, f.NumValues())
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addPhiCopies(f) // add copies of phi inputs in preceeding blocks
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// Compute live values at the end of each block.
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live := live(f)
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lastUse := make([]int, f.NumValues())
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var oldSched []*Value
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// Register allocate each block separately. All live values will live
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// in home locations (stack slots) between blocks.
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for _, b := range f.Blocks {
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// Compute the index of the last use of each Value in the Block.
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// Scheduling has already happened, so Values are totally ordered.
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// lastUse[x] = max(i) where b.Value[i] uses Value x.
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for i, v := range b.Values {
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lastUse[v.ID] = -1
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for _, w := range v.Args {
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// could condition this store on w.Block == b, but no need
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lastUse[w.ID] = i
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}
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}
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// Values which are live at block exit have a lastUse of len(b.Values).
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if b.Control != nil {
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lastUse[b.Control.ID] = len(b.Values)
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}
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// Values live after block exit have a lastUse of len(b.Values)+1.
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for _, vid := range live[b.ID] {
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lastUse[vid] = len(b.Values) + 1
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}
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// For each register, store which value it contains
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type regInfo struct {
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v *Value // stack-homed original value (or nil if empty)
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c *Value // the register copy of v
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dirty bool // if the stack-homed copy is out of date
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}
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regs := make([]regInfo, numRegs)
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var used regMask // has a 1 for each non-nil entry in regs
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var dirty regMask // has a 1 for each dirty entry in regs
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oldSched = append(oldSched[:0], b.Values...)
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b.Values = b.Values[:0]
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for idx, v := range oldSched {
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// For each instruction, do:
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// set up inputs to v in registers
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// pick output register
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// run insn
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// mark output register as dirty
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// Note that v represents the Value at "home" (on the stack), and c
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// is its register equivalent. There are two ways to establish c:
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// - use of v. c will be a load from v's home.
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// - definition of v. c will be identical to v but will live in
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// a register. v will be modified into a spill of c.
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regspec := opcodeTable[v.Op].reg
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if v.Op == OpConvNop {
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regspec = opcodeTable[v.Args[0].Op].reg
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}
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inputs := regspec[0]
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outputs := regspec[1]
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if len(inputs) == 0 && len(outputs) == 0 {
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// No register allocation required (or none specified yet)
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b.Values = append(b.Values, v)
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continue
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}
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// Compute a good input ordering. Start with the most constrained input.
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order := make([]intPair, len(inputs))
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for i, input := range inputs {
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order[i] = intPair{countRegs(input), i}
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}
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sort.Sort(byKey(order))
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// nospill contains registers that we can't spill because
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// we already set them up for use by the current instruction.
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var nospill regMask
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// Move inputs into registers
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for _, o := range order {
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w := v.Args[o.val]
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mask := inputs[o.val]
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if mask == 0 {
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// Input doesn't need a register
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continue
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}
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// TODO: 2-address overwrite instructions
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// Find registers that w is already in
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var wreg regMask
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for r := register(0); r < numRegs; r++ {
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if regs[r].v == w {
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wreg |= regMask(1) << r
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}
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}
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var r register
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if mask&wreg != 0 {
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// w is already in an allowed register. We're done.
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r = pickReg(mask & wreg)
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} else {
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// Pick a register for w
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// Priorities (in order)
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// - an unused register
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// - a clean register
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// - a dirty register
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// TODO: for used registers, pick the one whose next use is the
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// farthest in the future.
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mask &^= nospill
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if mask & ^dirty != 0 {
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mask &^= dirty
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}
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if mask & ^used != 0 {
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mask &^= used
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}
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r = pickReg(mask)
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// Kick out whomever is using this register.
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if regs[r].v != nil {
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x := regs[r].v
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c := regs[r].c
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if regs[r].dirty && lastUse[x.ID] > idx {
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// Write x back to home. Its value is currently held in c.
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x.Op = OpStoreReg8
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x.Aux = nil
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x.resetArgs()
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x.AddArg(c)
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b.Values = append(b.Values, x)
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regs[r].dirty = false
|
||||
dirty &^= regMask(1) << r
|
||||
}
|
||||
regs[r].v = nil
|
||||
regs[r].c = nil
|
||||
used &^= regMask(1) << r
|
||||
}
|
||||
|
||||
// Load w into this register
|
||||
var c *Value
|
||||
if w.Op == OpConst {
|
||||
// Materialize w
|
||||
// TODO: arch-specific MOV op
|
||||
c = b.NewValue(OpMOVQconst, w.Type, w.Aux)
|
||||
} else if wreg != 0 {
|
||||
// Copy from another register.
|
||||
// Typically just an optimization, but this is
|
||||
// required if w is dirty.
|
||||
s := pickReg(wreg)
|
||||
// inv: s != r
|
||||
c = b.NewValue(OpCopy, w.Type, nil)
|
||||
c.AddArg(regs[s].c)
|
||||
} else {
|
||||
// Load from home location
|
||||
c = b.NewValue(OpLoadReg8, w.Type, nil)
|
||||
c.AddArg(w)
|
||||
}
|
||||
home = setloc(home, c, ®isters[r])
|
||||
// Remember what we did
|
||||
regs[r].v = w
|
||||
regs[r].c = c
|
||||
regs[r].dirty = false
|
||||
used |= regMask(1) << r
|
||||
}
|
||||
|
||||
// Replace w with its in-register copy.
|
||||
v.SetArg(o.val, regs[r].c)
|
||||
|
||||
// Remember not to undo this register assignment until after
|
||||
// the instruction is issued.
|
||||
nospill |= regMask(1) << r
|
||||
}
|
||||
|
||||
// pick a register for v itself.
|
||||
if len(outputs) > 1 {
|
||||
panic("can't do multi-output yet")
|
||||
}
|
||||
if len(outputs) == 0 || outputs[0] == 0 {
|
||||
// output doesn't need a register
|
||||
b.Values = append(b.Values, v)
|
||||
} else {
|
||||
mask := outputs[0]
|
||||
if mask & ^dirty != 0 {
|
||||
mask &^= dirty
|
||||
}
|
||||
if mask & ^used != 0 {
|
||||
mask &^= used
|
||||
}
|
||||
r := pickReg(mask)
|
||||
|
||||
// Kick out whomever is using this register.
|
||||
if regs[r].v != nil {
|
||||
x := regs[r].v
|
||||
c := regs[r].c
|
||||
if regs[r].dirty && lastUse[x.ID] > idx {
|
||||
// Write x back to home. Its value is currently held in c.
|
||||
x.Op = OpStoreReg8
|
||||
x.Aux = nil
|
||||
x.resetArgs()
|
||||
x.AddArg(c)
|
||||
b.Values = append(b.Values, x)
|
||||
regs[r].dirty = false
|
||||
dirty &^= regMask(1) << r
|
||||
}
|
||||
regs[r].v = nil
|
||||
regs[r].c = nil
|
||||
used &^= regMask(1) << r
|
||||
}
|
||||
|
||||
// Reissue v with new op, with r as its home.
|
||||
c := b.NewValue(v.Op, v.Type, v.Aux)
|
||||
c.AddArgs(v.Args...)
|
||||
home = setloc(home, c, ®isters[r])
|
||||
|
||||
// Remember what we did
|
||||
regs[r].v = v
|
||||
regs[r].c = c
|
||||
regs[r].dirty = true
|
||||
used |= regMask(1) << r
|
||||
dirty |= regMask(1) << r
|
||||
}
|
||||
}
|
||||
|
||||
// If the block ends in a call, we must put the call after the spill code.
|
||||
var call *Value
|
||||
if b.Kind == BlockCall {
|
||||
call = b.Control
|
||||
if call != b.Values[len(b.Values)-1] {
|
||||
log.Fatalf("call not at end of block %b %v", b, call)
|
||||
}
|
||||
b.Values = b.Values[:len(b.Values)-1]
|
||||
// TODO: do this for all control types?
|
||||
}
|
||||
|
||||
// at the end of the block, spill any remaining dirty, live values
|
||||
for r := register(0); r < numRegs; r++ {
|
||||
if !regs[r].dirty {
|
||||
continue
|
||||
}
|
||||
v := regs[r].v
|
||||
c := regs[r].c
|
||||
if lastUse[v.ID] <= len(oldSched) {
|
||||
continue // not live after block
|
||||
}
|
||||
|
||||
// change v to be a copy of c
|
||||
v.Op = OpStoreReg8
|
||||
v.Aux = nil
|
||||
v.resetArgs()
|
||||
v.AddArg(c)
|
||||
b.Values = append(b.Values, v)
|
||||
}
|
||||
|
||||
// add call back after spills
|
||||
if b.Kind == BlockCall {
|
||||
b.Values = append(b.Values, call)
|
||||
}
|
||||
}
|
||||
f.RegAlloc = home
|
||||
}
|
||||
|
||||
// addPhiCopies adds copies of phi inputs in the blocks
|
||||
// immediately preceding the phi's block.
|
||||
func addPhiCopies(f *Func) {
|
||||
for _, b := range f.Blocks {
|
||||
for _, v := range b.Values {
|
||||
if v.Op != OpPhi {
|
||||
break // all phis should appear first
|
||||
}
|
||||
if v.Type.IsMemory() { // TODO: only "regallocable" types
|
||||
continue
|
||||
}
|
||||
for i, w := range v.Args {
|
||||
c := b.Preds[i]
|
||||
cpy := c.NewValue1(OpCopy, v.Type, nil, w)
|
||||
v.Args[i] = cpy
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// live returns a map from block ID to a list of value IDs live at the end of that block
|
||||
// TODO: this could be quadratic if lots of variables are live across lots of
|
||||
// basic blocks. Figure out a way to make this function (or, more precisely, the user
|
||||
// of this function) require only linear size & time.
|
||||
func live(f *Func) [][]ID {
|
||||
live := make([][]ID, f.NumBlocks())
|
||||
var phis []*Value
|
||||
|
||||
s := newSparseSet(f.NumValues())
|
||||
t := newSparseSet(f.NumValues())
|
||||
for {
|
||||
for _, b := range f.Blocks {
|
||||
fmt.Printf("live %s %v\n", b, live[b.ID])
|
||||
}
|
||||
changed := false
|
||||
|
||||
for _, b := range f.Blocks {
|
||||
// Start with known live values at the end of the block
|
||||
s.clear()
|
||||
s.addAll(live[b.ID])
|
||||
|
||||
// Propagate backwards to the start of the block
|
||||
// Assumes Values have been scheduled.
|
||||
phis := phis[:0]
|
||||
for i := len(b.Values) - 1; i >= 0; i-- {
|
||||
v := b.Values[i]
|
||||
s.remove(v.ID)
|
||||
if v.Op == OpPhi {
|
||||
// save phi ops for later
|
||||
phis = append(phis, v)
|
||||
continue
|
||||
}
|
||||
s.addAllValues(v.Args)
|
||||
}
|
||||
|
||||
// for each predecessor of b, expand its list of live-at-end values
|
||||
// inv: s contains the values live at the start of b (excluding phi inputs)
|
||||
for i, p := range b.Preds {
|
||||
t.clear()
|
||||
t.addAll(live[p.ID])
|
||||
t.addAll(s.contents())
|
||||
for _, v := range phis {
|
||||
t.add(v.Args[i].ID)
|
||||
}
|
||||
if t.size() == len(live[p.ID]) {
|
||||
continue
|
||||
}
|
||||
// grow p's live set
|
||||
c := make([]ID, t.size())
|
||||
copy(c, t.contents())
|
||||
live[p.ID] = c
|
||||
changed = true
|
||||
}
|
||||
}
|
||||
|
||||
if !changed {
|
||||
break
|
||||
}
|
||||
}
|
||||
return live
|
||||
}
|
||||
|
||||
// for sorting a pair of integers by key
|
||||
type intPair struct {
|
||||
key, val int
|
||||
}
|
||||
type byKey []intPair
|
||||
|
||||
func (a byKey) Len() int { return len(a) }
|
||||
func (a byKey) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
|
||||
func (a byKey) Less(i, j int) bool { return a[i].key < a[j].key }
|
@ -28,9 +28,24 @@ func (s *sparseSet) contains(x ID) bool {
|
||||
}
|
||||
|
||||
func (s *sparseSet) add(x ID) {
|
||||
i := len(s.dense)
|
||||
i := s.sparse[x]
|
||||
if i < len(s.dense) && s.dense[i] == x {
|
||||
return
|
||||
}
|
||||
s.dense = append(s.dense, x)
|
||||
s.sparse[x] = i
|
||||
s.sparse[x] = len(s.dense) - 1
|
||||
}
|
||||
|
||||
func (s *sparseSet) addAll(a []ID) {
|
||||
for _, x := range a {
|
||||
s.add(x)
|
||||
}
|
||||
}
|
||||
|
||||
func (s *sparseSet) addAllValues(a []*Value) {
|
||||
for _, v := range a {
|
||||
s.add(v.ID)
|
||||
}
|
||||
}
|
||||
|
||||
func (s *sparseSet) remove(x ID) {
|
||||
|
51
src/cmd/internal/ssa/stackalloc.go
Normal file
51
src/cmd/internal/ssa/stackalloc.go
Normal file
@ -0,0 +1,51 @@
|
||||
package ssa
|
||||
|
||||
// stackalloc allocates storage in the stack frame for
|
||||
// all Values that did not get a register.
|
||||
func stackalloc(f *Func) {
|
||||
home := f.RegAlloc
|
||||
|
||||
var n int64 = 8 // 8 = space for return address. TODO: arch-dependent
|
||||
|
||||
// Assign stack locations to phis first, because we
|
||||
// must also assign the same locations to the phi copies
|
||||
// introduced during regalloc.
|
||||
for _, b := range f.Blocks {
|
||||
for _, v := range b.Values {
|
||||
if v.Op != OpPhi {
|
||||
continue
|
||||
}
|
||||
n += v.Type.Size()
|
||||
// a := v.Type.Align()
|
||||
// n = (n + a - 1) / a * a TODO
|
||||
loc := &LocalSlot{n}
|
||||
home = setloc(home, v, loc)
|
||||
for _, w := range v.Args {
|
||||
home = setloc(home, w, loc)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Now do all other unassigned values.
|
||||
for _, b := range f.Blocks {
|
||||
for _, v := range b.Values {
|
||||
if v.ID < ID(len(home)) && home[v.ID] != nil {
|
||||
continue
|
||||
}
|
||||
if v.Type.IsMemory() { // TODO: only "regallocable" types
|
||||
continue
|
||||
}
|
||||
// a := v.Type.Align()
|
||||
// n = (n + a - 1) / a * a TODO
|
||||
n += v.Type.Size()
|
||||
loc := &LocalSlot{n}
|
||||
home = setloc(home, v, loc)
|
||||
}
|
||||
}
|
||||
f.RegAlloc = home
|
||||
|
||||
// TODO: share stack slots among noninterfering (& gc type compatible) values
|
||||
// TODO: align final n
|
||||
// TODO: compute total frame size: n + max paramout space
|
||||
// TODO: save total size somewhere
|
||||
}
|
Loading…
Reference in New Issue
Block a user