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| author | Than McIntosh <thanm@google.com> | 2021-05-04 13:24:11 -0400 |
|---|---|---|
| committer | Than McIntosh <thanm@google.com> | 2021-05-04 19:56:15 +0000 |
| commit | f62739b8611a0f1c96e59eb6574422562bb46233 (patch) | |
| tree | ee5428662b81326356f3320bbf74f1c5cea1d57e /src/cmd/compile/internal/ssa | |
| parent | 8c3d217d89e718a5d9b7d8f4b1336907f15ea50c (diff) | |
| download | go-f62739b8611a0f1c96e59eb6574422562bb46233.tar.gz go-f62739b8611a0f1c96e59eb6574422562bb46233.zip | |
cmd/compile: establish regabi name/value mapping for small in-params
When the expand_calls phase in the SSA backend lowers prolog OpArg
values into OpArgIntReg/OpArgFloatReg values, we don't always record
the assocation between the new lowered value and the parameter name.
This patch handles the simple case where a given parameter fits into
exactly one register; in this scenario it makes sense to manufacture a
new pseudo-slot for the value that points to the param, and install
the slot/value mapping in the NamedValues table for the function. More
work will be needed to deal with params that span multiple registers;
that will need to be addressed in a subsequent patch.
This change improves the parameter error rate "optargorder" benchmark
by about 7-8% (when run on the optargorder binary).
Updates #45945.
Change-Id: Ic9adbe20b6f91145d49651348818f0f5cba92b18
Reviewed-on: https://go-review.googlesource.com/c/go/+/316890
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa')
| -rw-r--r-- | src/cmd/compile/internal/ssa/expand_calls.go | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go index 39d0b61c2e..2852753bee 100644 --- a/src/cmd/compile/internal/ssa/expand_calls.go +++ b/src/cmd/compile/internal/ssa/expand_calls.go @@ -1714,6 +1714,21 @@ func (x *expandState) newArgToMemOrRegs(baseArg, toReplace *Value, offset int64, } else { w = baseArg.Block.NewValue0IA(pos, op, t, auxInt, aux) } + // If we are creating an OpArgIntReg/OpArgFloatReg that + // corresponds to an in-param that fits entirely in a register, + // then enter it into the name/value table. The LocalSlot + // is somewhat fictitious, since there is no incoming live + // memory version of the parameter, but we need an entry in + // NamedValues in order for ssa debug tracking to include + // the value in the tracking analysis. + if len(pa.Registers) == 1 { + loc := LocalSlot{N: aux.Name, Type: t, Off: 0} + values, ok := x.f.NamedValues[loc] + if !ok { + x.f.Names = append(x.f.Names, loc) + } + x.f.NamedValues[loc] = append(values, w) + } x.commonArgs[key] = w if toReplace != nil { toReplace.copyOf(w) |