cmd/compile: re-enable nilcheck removal for newobject
Also add compiler debug ouput and add a test.
Fixes #15390.
Change-Id: Iceba1414c29bcc213b87837387bf8ded1f3157f1
Reviewed-on: https://go-review.googlesource.com/30011
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/cmd/compile/internal/ssa/config.go b/src/cmd/compile/internal/ssa/config.go
index 1b51f7f..201dcd4 100644
--- a/src/cmd/compile/internal/ssa/config.go
+++ b/src/cmd/compile/internal/ssa/config.go
@@ -17,6 +17,7 @@
arch string // "amd64", etc.
IntSize int64 // 4 or 8
PtrSize int64 // 4 or 8
+ RegSize int64 // 4 or 8
lowerBlock func(*Block, *Config) bool // lowering function
lowerValue func(*Value, *Config) bool // lowering function
registers []Register // machine registers
@@ -132,6 +133,7 @@
case "amd64":
c.IntSize = 8
c.PtrSize = 8
+ c.RegSize = 8
c.lowerBlock = rewriteBlockAMD64
c.lowerValue = rewriteValueAMD64
c.registers = registersAMD64[:]
@@ -142,6 +144,7 @@
case "amd64p32":
c.IntSize = 4
c.PtrSize = 4
+ c.RegSize = 8
c.lowerBlock = rewriteBlockAMD64
c.lowerValue = rewriteValueAMD64
c.registers = registersAMD64[:]
@@ -153,6 +156,7 @@
case "386":
c.IntSize = 4
c.PtrSize = 4
+ c.RegSize = 4
c.lowerBlock = rewriteBlock386
c.lowerValue = rewriteValue386
c.registers = registers386[:]
@@ -163,6 +167,7 @@
case "arm":
c.IntSize = 4
c.PtrSize = 4
+ c.RegSize = 4
c.lowerBlock = rewriteBlockARM
c.lowerValue = rewriteValueARM
c.registers = registersARM[:]
@@ -173,6 +178,7 @@
case "arm64":
c.IntSize = 8
c.PtrSize = 8
+ c.RegSize = 8
c.lowerBlock = rewriteBlockARM64
c.lowerValue = rewriteValueARM64
c.registers = registersARM64[:]
@@ -187,6 +193,7 @@
case "ppc64le":
c.IntSize = 8
c.PtrSize = 8
+ c.RegSize = 8
c.lowerBlock = rewriteBlockPPC64
c.lowerValue = rewriteValuePPC64
c.registers = registersPPC64[:]
@@ -199,6 +206,7 @@
case "mips64", "mips64le":
c.IntSize = 8
c.PtrSize = 8
+ c.RegSize = 8
c.lowerBlock = rewriteBlockMIPS64
c.lowerValue = rewriteValueMIPS64
c.registers = registersMIPS64[:]
@@ -210,6 +218,7 @@
case "s390x":
c.IntSize = 8
c.PtrSize = 8
+ c.RegSize = 8
c.lowerBlock = rewriteBlockS390X
c.lowerValue = rewriteValueS390X
c.registers = registersS390X[:]
diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 7539a36..c0492b5 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -958,13 +958,15 @@
-> mem
// nil checks just need to rewrite to something useless.
// they will be deadcode eliminated soon afterwards.
- //(NilCheck (Load (OffPtr [c] (SP)) mem) mem)
- // && mem.Op == OpStaticCall
- // && isSameSym(mem.Aux, "runtime.newobject")
- // && c == config.ctxt.FixedFrameSize() + config.PtrSize // offset of return value
- // -> (Invalid)
- //(NilCheck (OffPtr (Load (OffPtr [c] (SP)) mem)) mem)
- // && mem.Op == OpStaticCall
- // && isSameSym(mem.Aux, "runtime.newobject")
- // && c == config.ctxt.FixedFrameSize() + config.PtrSize // offset of return value
- // -> (Invalid)
+(NilCheck (Load (OffPtr [c] (SP)) mem) mem)
+ && mem.Op == OpStaticCall
+ && isSameSym(mem.Aux, "runtime.newobject")
+ && c == config.ctxt.FixedFrameSize() + config.RegSize // offset of return value
+ && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")
+ -> (Invalid)
+(NilCheck (OffPtr (Load (OffPtr [c] (SP)) mem)) mem)
+ && mem.Op == OpStaticCall
+ && isSameSym(mem.Aux, "runtime.newobject")
+ && c == config.ctxt.FixedFrameSize() + config.RegSize // offset of return value
+ && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")
+ -> (Invalid)
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index 5d6710f..0a419f6 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -370,6 +370,15 @@
return true
}
+// warnRule generates a compiler debug output with string s when
+// cond is true and the rule is fired.
+func warnRule(cond bool, v *Value, s string) bool {
+ if cond {
+ v.Block.Func.Config.Warnl(v.Line, "removed nil check")
+ }
+ return true
+}
+
// logRule logs the use of the rule s. This will only be enabled if
// rewrite rules were generated with the -log option, see gen/rulegen.go.
func logRule(s string) {
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index ecb2901..7dff179 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -6380,6 +6380,64 @@
v.AddArg(mem)
return true
}
+ // match: (NilCheck (Load (OffPtr [c] (SP)) mem) mem)
+ // cond: mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize() + config.RegSize && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")
+ // result: (Invalid)
+ for {
+ v_0 := v.Args[0]
+ if v_0.Op != OpLoad {
+ break
+ }
+ v_0_0 := v_0.Args[0]
+ if v_0_0.Op != OpOffPtr {
+ break
+ }
+ c := v_0_0.AuxInt
+ v_0_0_0 := v_0_0.Args[0]
+ if v_0_0_0.Op != OpSP {
+ break
+ }
+ mem := v_0.Args[1]
+ if mem != v.Args[1] {
+ break
+ }
+ if !(mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize()+config.RegSize && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")) {
+ break
+ }
+ v.reset(OpInvalid)
+ return true
+ }
+ // match: (NilCheck (OffPtr (Load (OffPtr [c] (SP)) mem)) mem)
+ // cond: mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize() + config.RegSize && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")
+ // result: (Invalid)
+ for {
+ v_0 := v.Args[0]
+ if v_0.Op != OpOffPtr {
+ break
+ }
+ v_0_0 := v_0.Args[0]
+ if v_0_0.Op != OpLoad {
+ break
+ }
+ v_0_0_0 := v_0_0.Args[0]
+ if v_0_0_0.Op != OpOffPtr {
+ break
+ }
+ c := v_0_0_0.AuxInt
+ v_0_0_0_0 := v_0_0_0.Args[0]
+ if v_0_0_0_0.Op != OpSP {
+ break
+ }
+ mem := v_0_0.Args[1]
+ if mem != v.Args[1] {
+ break
+ }
+ if !(mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize()+config.RegSize && warnRule(config.Debug_checknil() && int(v.Line) > 1, v, "removed nil check")) {
+ break
+ }
+ v.reset(OpInvalid)
+ return true
+ }
return false
}
func rewriteValuegeneric_OpNot(v *Value, config *Config) bool {
