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From 11b283092a29a9d402ce05706fd3a85683576218 Mon Sep 17 00:00:00 2001
From: David Chase <drchase@google.com>
Date: Tue, 21 Feb 2017 15:22:52 -0500
Subject: [PATCH] cmd/compile: add opcode flag hasSideEffects for do-not-remove
Added a flag to generic and various architectures' atomic
operations that are judged to have observable side effects
and thus cannot be dead-code-eliminated.
Test requires GOMAXPROCS > 1 without preemption in loop.
Fixes #19182.
Change-Id: Id2230031abd2cca0bbb32fd68fc8a58fb912070f
Reviewed-on: https://go-review.googlesource.com/37333
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---
src/cmd/compile/internal/ssa/deadcode.go | 2 +-
src/cmd/compile/internal/ssa/gen/AMD64Ops.go | 16 ++--
src/cmd/compile/internal/ssa/gen/ARM64Ops.go | 20 ++---
src/cmd/compile/internal/ssa/gen/MIPSOps.go | 16 ++--
src/cmd/compile/internal/ssa/gen/S390XOps.go | 16 ++--
src/cmd/compile/internal/ssa/gen/genericOps.go | 28 +++----
src/cmd/compile/internal/ssa/gen/main.go | 4 +
src/cmd/compile/internal/ssa/op.go | 1 +
src/cmd/compile/internal/ssa/opGen.go | 111 +++++++++++++++++--------
test/fixedbugs/issue19182.go | 36 ++++++++
10 files changed, 168 insertions(+), 82 deletions(-)
create mode 100644 test/fixedbugs/issue19182.go
diff --git a/src/cmd/compile/internal/ssa/deadcode.go b/src/cmd/compile/internal/ssa/deadcode.go
index d75d2d5..ce786a9 100644
--- a/src/cmd/compile/internal/ssa/deadcode.go
+++ b/src/cmd/compile/internal/ssa/deadcode.go
@@ -64,7 +64,7 @@ func liveValues(f *Func, reachable []bool) []bool {
q = append(q, v)
}
for _, v := range b.Values {
- if opcodeTable[v.Op].call && !live[v.ID] {
+ if (opcodeTable[v.Op].call || opcodeTable[v.Op].hasSideEffects) && !live[v.ID] {
live[v.ID] = true
q = append(q, v)
}
diff --git a/src/cmd/compile/internal/ssa/gen/AMD64Ops.go b/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
index cdd5539..1b73ac1 100644
--- a/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
@@ -548,15 +548,15 @@ func init() {
// store arg0 to arg1+auxint+aux, arg2=mem.
// These ops return a tuple of <old contents of *(arg1+auxint+aux), memory>.
// Note: arg0 and arg1 are backwards compared to MOVLstore (to facilitate resultInArg0)!
- {name: "XCHGL", argLength: 3, reg: gpstorexchg, asm: "XCHGL", aux: "SymOff", resultInArg0: true, faultOnNilArg1: true},
- {name: "XCHGQ", argLength: 3, reg: gpstorexchg, asm: "XCHGQ", aux: "SymOff", resultInArg0: true, faultOnNilArg1: true},
+ {name: "XCHGL", argLength: 3, reg: gpstorexchg, asm: "XCHGL", aux: "SymOff", resultInArg0: true, faultOnNilArg1: true, hasSideEffects: true},
+ {name: "XCHGQ", argLength: 3, reg: gpstorexchg, asm: "XCHGQ", aux: "SymOff", resultInArg0: true, faultOnNilArg1: true, hasSideEffects: true},
// Atomic adds.
// *(arg1+auxint+aux) += arg0. arg2=mem.
// Returns a tuple of <old contents of *(arg1+auxint+aux), memory>.
// Note: arg0 and arg1 are backwards compared to MOVLstore (to facilitate resultInArg0)!
- {name: "XADDLlock", argLength: 3, reg: gpstorexchg, asm: "XADDL", typ: "(UInt32,Mem)", aux: "SymOff", resultInArg0: true, clobberFlags: true, faultOnNilArg1: true},
- {name: "XADDQlock", argLength: 3, reg: gpstorexchg, asm: "XADDQ", typ: "(UInt64,Mem)", aux: "SymOff", resultInArg0: true, clobberFlags: true, faultOnNilArg1: true},
+ {name: "XADDLlock", argLength: 3, reg: gpstorexchg, asm: "XADDL", typ: "(UInt32,Mem)", aux: "SymOff", resultInArg0: true, clobberFlags: true, faultOnNilArg1: true, hasSideEffects: true},
+ {name: "XADDQlock", argLength: 3, reg: gpstorexchg, asm: "XADDQ", typ: "(UInt64,Mem)", aux: "SymOff", resultInArg0: true, clobberFlags: true, faultOnNilArg1: true, hasSideEffects: true},
{name: "AddTupleFirst32", argLength: 2}, // arg0=tuple <x,y>. Returns <x+arg1,y>.
{name: "AddTupleFirst64", argLength: 2}, // arg0=tuple <x,y>. Returns <x+arg1,y>.
@@ -579,12 +579,12 @@ func init() {
// JEQ ...
// but we can't do that because memory-using ops can't generate flags yet
// (flagalloc wants to move flag-generating instructions around).
- {name: "CMPXCHGLlock", argLength: 4, reg: cmpxchg, asm: "CMPXCHGL", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
- {name: "CMPXCHGQlock", argLength: 4, reg: cmpxchg, asm: "CMPXCHGQ", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
+ {name: "CMPXCHGLlock", argLength: 4, reg: cmpxchg, asm: "CMPXCHGL", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "CMPXCHGQlock", argLength: 4, reg: cmpxchg, asm: "CMPXCHGQ", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
// Atomic memory updates.
- {name: "ANDBlock", argLength: 3, reg: gpstore, asm: "ANDB", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true}, // *(arg0+auxint+aux) &= arg1
- {name: "ORBlock", argLength: 3, reg: gpstore, asm: "ORB", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true}, // *(arg0+auxint+aux) |= arg1
+ {name: "ANDBlock", argLength: 3, reg: gpstore, asm: "ANDB", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true}, // *(arg0+auxint+aux) &= arg1
+ {name: "ORBlock", argLength: 3, reg: gpstore, asm: "ORB", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true}, // *(arg0+auxint+aux) |= arg1
}
var AMD64blocks = []blockData{
diff --git a/src/cmd/compile/internal/ssa/gen/ARM64Ops.go b/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
index e8d5be2..0986ac6 100644
--- a/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/ARM64Ops.go
@@ -456,16 +456,16 @@ func init() {
// atomic stores.
// store arg1 to arg0. arg2=mem. returns memory. auxint must be zero.
- {name: "STLR", argLength: 3, reg: gpstore, asm: "STLR", faultOnNilArg0: true},
- {name: "STLRW", argLength: 3, reg: gpstore, asm: "STLRW", faultOnNilArg0: true},
+ {name: "STLR", argLength: 3, reg: gpstore, asm: "STLR", faultOnNilArg0: true, hasSideEffects: true},
+ {name: "STLRW", argLength: 3, reg: gpstore, asm: "STLRW", faultOnNilArg0: true, hasSideEffects: true},
// atomic exchange.
// store arg1 to arg0. arg2=mem. returns <old content of *arg0, memory>. auxint must be zero.
// LDAXR (Rarg0), Rout
// STLXR Rarg1, (Rarg0), Rtmp
// CBNZ Rtmp, -2(PC)
- {name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
- {name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic add.
// *arg0 += arg1. arg2=mem. returns <new content of *arg0, memory>. auxint must be zero.
@@ -473,8 +473,8 @@ func init() {
// ADD Rarg1, Rout
// STLXR Rout, (Rarg0), Rtmp
// CBNZ Rtmp, -3(PC)
- {name: "LoweredAtomicAdd64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
- {name: "LoweredAtomicAdd32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicAdd64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicAdd32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic compare and swap.
// arg0 = pointer, arg1 = old value, arg2 = new value, arg3 = memory. auxint must be zero.
@@ -490,8 +490,8 @@ func init() {
// STLXR Rarg2, (Rarg0), Rtmp
// CBNZ Rtmp, -4(PC)
// CSET EQ, Rout
- {name: "LoweredAtomicCas64", argLength: 4, reg: gpcas, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true},
- {name: "LoweredAtomicCas32", argLength: 4, reg: gpcas, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicCas64", argLength: 4, reg: gpcas, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicCas32", argLength: 4, reg: gpcas, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic and/or.
// *arg0 &= (|=) arg1. arg2=mem. returns memory. auxint must be zero.
@@ -499,8 +499,8 @@ func init() {
// AND/OR Rarg1, Rtmp
// STLXRB Rtmp, (Rarg0), Rtmp
// CBNZ Rtmp, -3(PC)
- {name: "LoweredAtomicAnd8", argLength: 3, reg: gpstore, asm: "AND", faultOnNilArg0: true},
- {name: "LoweredAtomicOr8", argLength: 3, reg: gpstore, asm: "ORR", faultOnNilArg0: true},
+ {name: "LoweredAtomicAnd8", argLength: 3, reg: gpstore, asm: "AND", faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicOr8", argLength: 3, reg: gpstore, asm: "ORR", faultOnNilArg0: true, hasSideEffects: true},
}
blocks := []blockData{
diff --git a/src/cmd/compile/internal/ssa/gen/MIPSOps.go b/src/cmd/compile/internal/ssa/gen/MIPSOps.go
index 78b961f..3d88b71 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPSOps.go
+++ b/src/cmd/compile/internal/ssa/gen/MIPSOps.go
@@ -267,8 +267,8 @@ func init() {
// SYNC
// MOVW Rarg1, (Rarg0)
// SYNC
- {name: "LoweredAtomicStore", argLength: 3, reg: gpstore, faultOnNilArg0: true},
- {name: "LoweredAtomicStorezero", argLength: 2, reg: gpstore0, faultOnNilArg0: true},
+ {name: "LoweredAtomicStore", argLength: 3, reg: gpstore, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicStorezero", argLength: 2, reg: gpstore0, faultOnNilArg0: true, hasSideEffects: true},
// atomic exchange.
// store arg1 to arg0. arg2=mem. returns <old content of *arg0, memory>.
@@ -278,7 +278,7 @@ func init() {
// SC Rtmp, (Rarg0)
// BEQ Rtmp, -3(PC)
// SYNC
- {name: "LoweredAtomicExchange", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicExchange", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic add.
// *arg0 += arg1. arg2=mem. returns <new content of *arg0, memory>.
@@ -289,8 +289,8 @@ func init() {
// BEQ Rtmp, -3(PC)
// SYNC
// ADDU Rarg1, Rout
- {name: "LoweredAtomicAdd", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true},
- {name: "LoweredAtomicAddconst", argLength: 2, reg: regInfo{inputs: []regMask{gpspsbg}, outputs: []regMask{gp}}, aux: "Int32", resultNotInArgs: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicAdd", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicAddconst", argLength: 2, reg: regInfo{inputs: []regMask{gpspsbg}, outputs: []regMask{gp}}, aux: "Int32", resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic compare and swap.
// arg0 = pointer, arg1 = old value, arg2 = new value, arg3 = memory.
@@ -308,7 +308,7 @@ func init() {
// SC Rout, (Rarg0)
// BEQ Rout, -4(PC)
// SYNC
- {name: "LoweredAtomicCas", argLength: 4, reg: gpcas, resultNotInArgs: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicCas", argLength: 4, reg: gpcas, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
// atomic and/or.
// *arg0 &= (|=) arg1. arg2=mem. returns memory.
@@ -318,8 +318,8 @@ func init() {
// SC Rtmp, (Rarg0)
// BEQ Rtmp, -3(PC)
// SYNC
- {name: "LoweredAtomicAnd", argLength: 3, reg: gpstore, asm: "AND", faultOnNilArg0: true},
- {name: "LoweredAtomicOr", argLength: 3, reg: gpstore, asm: "OR", faultOnNilArg0: true},
+ {name: "LoweredAtomicAnd", argLength: 3, reg: gpstore, asm: "AND", faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicOr", argLength: 3, reg: gpstore, asm: "OR", faultOnNilArg0: true, hasSideEffects: true},
// large or unaligned zeroing
// arg0 = address of memory to zero (in R1, changed as side effect)
diff --git a/src/cmd/compile/internal/ssa/gen/S390XOps.go b/src/cmd/compile/internal/ssa/gen/S390XOps.go
index 4c5f070..40ba252 100644
--- a/src/cmd/compile/internal/ssa/gen/S390XOps.go
+++ b/src/cmd/compile/internal/ssa/gen/S390XOps.go
@@ -429,14 +429,14 @@ func init() {
// Atomic stores. These are just normal stores.
// store arg1 to arg0+auxint+aux. arg2=mem.
- {name: "MOVWatomicstore", argLength: 3, reg: gpstore, asm: "MOVW", aux: "SymOff", typ: "Mem", clobberFlags: true, faultOnNilArg0: true},
- {name: "MOVDatomicstore", argLength: 3, reg: gpstore, asm: "MOVD", aux: "SymOff", typ: "Mem", clobberFlags: true, faultOnNilArg0: true},
+ {name: "MOVWatomicstore", argLength: 3, reg: gpstore, asm: "MOVW", aux: "SymOff", typ: "Mem", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "MOVDatomicstore", argLength: 3, reg: gpstore, asm: "MOVD", aux: "SymOff", typ: "Mem", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
// Atomic adds.
// *(arg0+auxint+aux) += arg1. arg2=mem.
// Returns a tuple of <old contents of *(arg0+auxint+aux), memory>.
- {name: "LAA", argLength: 3, reg: gpstorelaa, asm: "LAA", typ: "(UInt32,Mem)", aux: "SymOff", faultOnNilArg0: true},
- {name: "LAAG", argLength: 3, reg: gpstorelaa, asm: "LAAG", typ: "(UInt64,Mem)", aux: "SymOff", faultOnNilArg0: true},
+ {name: "LAA", argLength: 3, reg: gpstorelaa, asm: "LAA", typ: "(UInt32,Mem)", aux: "SymOff", faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LAAG", argLength: 3, reg: gpstorelaa, asm: "LAAG", typ: "(UInt64,Mem)", aux: "SymOff", faultOnNilArg0: true, hasSideEffects: true},
{name: "AddTupleFirst32", argLength: 2}, // arg0=tuple <x,y>. Returns <x+arg1,y>.
{name: "AddTupleFirst64", argLength: 2}, // arg0=tuple <x,y>. Returns <x+arg1,y>.
@@ -461,13 +461,13 @@ func init() {
// BEQ ...
// but we can't do that because memory-using ops can't generate flags yet
// (flagalloc wants to move flag-generating instructions around).
- {name: "LoweredAtomicCas32", argLength: 4, reg: cas, asm: "CS", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
- {name: "LoweredAtomicCas64", argLength: 4, reg: cas, asm: "CSG", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicCas32", argLength: 4, reg: cas, asm: "CS", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicCas64", argLength: 4, reg: cas, asm: "CSG", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
// Lowered atomic swaps, emulated using compare-and-swap.
// store arg1 to arg0+auxint+aux, arg2=mem.
- {name: "LoweredAtomicExchange32", argLength: 3, reg: exchange, asm: "CS", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
- {name: "LoweredAtomicExchange64", argLength: 3, reg: exchange, asm: "CSG", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true},
+ {name: "LoweredAtomicExchange32", argLength: 3, reg: exchange, asm: "CS", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
+ {name: "LoweredAtomicExchange64", argLength: 3, reg: exchange, asm: "CSG", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
// find leftmost one
{
diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index f39598e..3854a39 100644
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -441,20 +441,20 @@ var genericOps = []opData{
// Atomic loads return a new memory so that the loads are properly ordered
// with respect to other loads and stores.
// TODO: use for sync/atomic at some point.
- {name: "AtomicLoad32", argLength: 2, typ: "(UInt32,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
- {name: "AtomicLoad64", argLength: 2, typ: "(UInt64,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
- {name: "AtomicLoadPtr", argLength: 2, typ: "(BytePtr,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
- {name: "AtomicStore32", argLength: 3, typ: "Mem"}, // Store arg1 to *arg0. arg2=memory. Returns memory.
- {name: "AtomicStore64", argLength: 3, typ: "Mem"}, // Store arg1 to *arg0. arg2=memory. Returns memory.
- {name: "AtomicStorePtrNoWB", argLength: 3, typ: "Mem"}, // Store arg1 to *arg0. arg2=memory. Returns memory.
- {name: "AtomicExchange32", argLength: 3, typ: "(UInt32,Mem)"}, // Store arg1 to *arg0. arg2=memory. Returns old contents of *arg0 and new memory.
- {name: "AtomicExchange64", argLength: 3, typ: "(UInt64,Mem)"}, // Store arg1 to *arg0. arg2=memory. Returns old contents of *arg0 and new memory.
- {name: "AtomicAdd32", argLength: 3, typ: "(UInt32,Mem)"}, // Do *arg0 += arg1. arg2=memory. Returns sum and new memory.
- {name: "AtomicAdd64", argLength: 3, typ: "(UInt64,Mem)"}, // Do *arg0 += arg1. arg2=memory. Returns sum and new memory.
- {name: "AtomicCompareAndSwap32", argLength: 4, typ: "(Bool,Mem)"}, // if *arg0==arg1, then set *arg0=arg2. Returns true iff store happens and new memory.
- {name: "AtomicCompareAndSwap64", argLength: 4, typ: "(Bool,Mem)"}, // if *arg0==arg1, then set *arg0=arg2. Returns true iff store happens and new memory.
- {name: "AtomicAnd8", argLength: 3, typ: "Mem"}, // *arg0 &= arg1. arg2=memory. Returns memory.
- {name: "AtomicOr8", argLength: 3, typ: "Mem"}, // *arg0 |= arg1. arg2=memory. Returns memory.
+ {name: "AtomicLoad32", argLength: 2, typ: "(UInt32,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
+ {name: "AtomicLoad64", argLength: 2, typ: "(UInt64,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
+ {name: "AtomicLoadPtr", argLength: 2, typ: "(BytePtr,Mem)"}, // Load from arg0. arg1=memory. Returns loaded value and new memory.
+ {name: "AtomicStore32", argLength: 3, typ: "Mem", hasSideEffects: true}, // Store arg1 to *arg0. arg2=memory. Returns memory.
+ {name: "AtomicStore64", argLength: 3, typ: "Mem", hasSideEffects: true}, // Store arg1 to *arg0. arg2=memory. Returns memory.
+ {name: "AtomicStorePtrNoWB", argLength: 3, typ: "Mem", hasSideEffects: true}, // Store arg1 to *arg0. arg2=memory. Returns memory.
+ {name: "AtomicExchange32", argLength: 3, typ: "(UInt32,Mem)", hasSideEffects: true}, // Store arg1 to *arg0. arg2=memory. Returns old contents of *arg0 and new memory.
+ {name: "AtomicExchange64", argLength: 3, typ: "(UInt64,Mem)", hasSideEffects: true}, // Store arg1 to *arg0. arg2=memory. Returns old contents of *arg0 and new memory.
+ {name: "AtomicAdd32", argLength: 3, typ: "(UInt32,Mem)", hasSideEffects: true}, // Do *arg0 += arg1. arg2=memory. Returns sum and new memory.
+ {name: "AtomicAdd64", argLength: 3, typ: "(UInt64,Mem)", hasSideEffects: true}, // Do *arg0 += arg1. arg2=memory. Returns sum and new memory.
+ {name: "AtomicCompareAndSwap32", argLength: 4, typ: "(Bool,Mem)", hasSideEffects: true}, // if *arg0==arg1, then set *arg0=arg2. Returns true iff store happens and new memory.
+ {name: "AtomicCompareAndSwap64", argLength: 4, typ: "(Bool,Mem)", hasSideEffects: true}, // if *arg0==arg1, then set *arg0=arg2. Returns true iff store happens and new memory.
+ {name: "AtomicAnd8", argLength: 3, typ: "Mem", hasSideEffects: true}, // *arg0 &= arg1. arg2=memory. Returns memory.
+ {name: "AtomicOr8", argLength: 3, typ: "Mem", hasSideEffects: true}, // *arg0 |= arg1. arg2=memory. Returns memory.
}
// kind control successors implicit exit
diff --git a/src/cmd/compile/internal/ssa/gen/main.go b/src/cmd/compile/internal/ssa/gen/main.go
index 41199f7..19b904a 100644
--- a/src/cmd/compile/internal/ssa/gen/main.go
+++ b/src/cmd/compile/internal/ssa/gen/main.go
@@ -52,6 +52,7 @@ type opData struct {
faultOnNilArg0 bool // this op will fault if arg0 is nil (and aux encodes a small offset)
faultOnNilArg1 bool // this op will fault if arg1 is nil (and aux encodes a small offset)
usesScratch bool // this op requires scratch memory space
+ hasSideEffects bool // for "reasons", not to be eliminated. E.g., atomic store, #19182.
}
type blockData struct {
@@ -208,6 +209,9 @@ func genOp() {
if v.usesScratch {
fmt.Fprintln(w, "usesScratch: true,")
}
+ if v.hasSideEffects {
+ fmt.Fprintln(w, "hasSideEffects: true,")
+ }
if a.name == "generic" {
fmt.Fprintln(w, "generic:true,")
fmt.Fprintln(w, "},") // close op
diff --git a/src/cmd/compile/internal/ssa/op.go b/src/cmd/compile/internal/ssa/op.go
index 4c3164f..37b2f74 100644
--- a/src/cmd/compile/internal/ssa/op.go
+++ b/src/cmd/compile/internal/ssa/op.go
@@ -34,6 +34,7 @@ type opInfo struct {
faultOnNilArg0 bool // this op will fault if arg0 is nil (and aux encodes a small offset)
faultOnNilArg1 bool // this op will fault if arg1 is nil (and aux encodes a small offset)
usesScratch bool // this op requires scratch memory space
+ hasSideEffects bool // for "reasons", not to be eliminated. E.g., atomic store, #19182.
}
type inputInfo struct {
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 26bcbe0..7a96216 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -7632,6 +7632,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultInArg0: true,
faultOnNilArg1: true,
+ hasSideEffects: true,
asm: x86.AXCHGL,
reg: regInfo{
inputs: []inputInfo{
@@ -7649,6 +7650,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultInArg0: true,
faultOnNilArg1: true,
+ hasSideEffects: true,
asm: x86.AXCHGQ,
reg: regInfo{
inputs: []inputInfo{
@@ -7667,6 +7669,7 @@ var opcodeTable = [...]opInfo{
resultInArg0: true,
clobberFlags: true,
faultOnNilArg1: true,
+ hasSideEffects: true,
asm: x86.AXADDL,
reg: regInfo{
inputs: []inputInfo{
@@ -7685,6 +7688,7 @@ var opcodeTable = [...]opInfo{
resultInArg0: true,
clobberFlags: true,
faultOnNilArg1: true,
+ hasSideEffects: true,
asm: x86.AXADDQ,
reg: regInfo{
inputs: []inputInfo{
@@ -7712,6 +7716,7 @@ var opcodeTable = [...]opInfo{
argLen: 4,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: x86.ACMPXCHGL,
reg: regInfo{
inputs: []inputInfo{
@@ -7732,6 +7737,7 @@ var opcodeTable = [...]opInfo{
argLen: 4,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: x86.ACMPXCHGQ,
reg: regInfo{
inputs: []inputInfo{
@@ -7752,6 +7758,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: x86.AANDB,
reg: regInfo{
inputs: []inputInfo{
@@ -7766,6 +7773,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: x86.AORB,
reg: regInfo{
inputs: []inputInfo{
@@ -12982,6 +12990,7 @@ var opcodeTable = [...]opInfo{
name: "STLR",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: arm64.ASTLR,
reg: regInfo{
inputs: []inputInfo{
@@ -12994,6 +13003,7 @@ var opcodeTable = [...]opInfo{
name: "STLRW",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: arm64.ASTLRW,
reg: regInfo{
inputs: []inputInfo{
@@ -13007,6 +13017,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13022,6 +13033,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13037,6 +13049,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13052,6 +13065,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13068,6 +13082,7 @@ var opcodeTable = [...]opInfo{
resultNotInArgs: true,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13085,6 +13100,7 @@ var opcodeTable = [...]opInfo{
resultNotInArgs: true,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 805044223}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30
@@ -13100,6 +13116,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicAnd8",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: arm64.AAND,
reg: regInfo{
inputs: []inputInfo{
@@ -13112,6 +13129,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicOr8",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: arm64.AORR,
reg: regInfo{
inputs: []inputInfo{
@@ -14302,6 +14320,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicStore",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 469762046}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 g R31
@@ -14313,6 +14332,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicStorezero",
argLen: 2,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{0, 140738025226238}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 SP g R31 SB
@@ -14324,6 +14344,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 469762046}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 g R31
@@ -14339,6 +14360,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 469762046}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 g R31
@@ -14355,6 +14377,7 @@ var opcodeTable = [...]opInfo{
argLen: 2,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{0, 140738025226238}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 SP g R31 SB
@@ -14369,6 +14392,7 @@ var opcodeTable = [...]opInfo{
argLen: 4,
resultNotInArgs: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
reg: regInfo{
inputs: []inputInfo{
{1, 469762046}, // R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R24 R25 R28 g R31
@@ -14384,6 +14408,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicAnd",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: mips.AAND,
reg: regInfo{
inputs: []inputInfo{
@@ -14396,6 +14421,7 @@ var opcodeTable = [...]opInfo{
name: "LoweredAtomicOr",
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: mips.AOR,
reg: regInfo{
inputs: []inputInfo{
@@ -19839,6 +19865,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.AMOVW,
reg: regInfo{
inputs: []inputInfo{
@@ -19853,6 +19880,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.AMOVD,
reg: regInfo{
inputs: []inputInfo{
@@ -19866,6 +19894,7 @@ var opcodeTable = [...]opInfo{
auxType: auxSymOff,
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ALAA,
reg: regInfo{
inputs: []inputInfo{
@@ -19882,6 +19911,7 @@ var opcodeTable = [...]opInfo{
auxType: auxSymOff,
argLen: 3,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ALAAG,
reg: regInfo{
inputs: []inputInfo{
@@ -19909,6 +19939,7 @@ var opcodeTable = [...]opInfo{
argLen: 4,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ACS,
reg: regInfo{
inputs: []inputInfo{
@@ -19929,6 +19960,7 @@ var opcodeTable = [...]opInfo{
argLen: 4,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ACSG,
reg: regInfo{
inputs: []inputInfo{
@@ -19949,6 +19981,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ACS,
reg: regInfo{
inputs: []inputInfo{
@@ -19967,6 +20000,7 @@ var opcodeTable = [...]opInfo{
argLen: 3,
clobberFlags: true,
faultOnNilArg0: true,
+ hasSideEffects: true,
asm: s390x.ACSG,
reg: regInfo{
inputs: []inputInfo{
@@ -21738,59 +21772,70 @@ var opcodeTable = [...]opInfo{
generic: true,
},
{
- name: "AtomicStore32",
- argLen: 3,
- generic: true,
+ name: "AtomicStore32",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicStore64",
- argLen: 3,
- generic: true,
+ name: "AtomicStore64",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicStorePtrNoWB",
- argLen: 3,
- generic: true,
+ name: "AtomicStorePtrNoWB",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicExchange32",
- argLen: 3,
- generic: true,
+ name: "AtomicExchange32",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicExchange64",
- argLen: 3,
- generic: true,
+ name: "AtomicExchange64",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicAdd32",
- argLen: 3,
- generic: true,
+ name: "AtomicAdd32",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicAdd64",
- argLen: 3,
- generic: true,
+ name: "AtomicAdd64",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicCompareAndSwap32",
- argLen: 4,
- generic: true,
+ name: "AtomicCompareAndSwap32",
+ argLen: 4,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicCompareAndSwap64",
- argLen: 4,
- generic: true,
+ name: "AtomicCompareAndSwap64",
+ argLen: 4,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicAnd8",
- argLen: 3,
- generic: true,
+ name: "AtomicAnd8",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
{
- name: "AtomicOr8",
- argLen: 3,
- generic: true,
+ name: "AtomicOr8",
+ argLen: 3,
+ hasSideEffects: true,
+ generic: true,
},
}
diff --git a/test/fixedbugs/issue19182.go b/test/fixedbugs/issue19182.go
new file mode 100644
index 0000000..3a90ff4
--- /dev/null
+++ b/test/fixedbugs/issue19182.go
@@ -0,0 +1,36 @@
+// run
+
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+ "fmt"
+ "runtime"
+ "sync/atomic"
+ "time"
+)
+
+var a uint64 = 0
+
+func main() {
+ runtime.GOMAXPROCS(2) // With just 1, infinite loop never yields
+
+ go func() {
+ for {
+ atomic.AddUint64(&a, uint64(1))
+ }
+ }()
+
+ time.Sleep(10 * time.Millisecond) // Short sleep is enough in passing case
+ i, val := 0, atomic.LoadUint64(&a)
+ for ; val == 0 && i < 100; val, i = atomic.LoadUint64(&a), i+1 {
+ time.Sleep(100 * time.Millisecond)
+ }
+ if val == 0 {
+ fmt.Printf("Failed to observe atomic increment after %d tries\n", i)
+ }
+
+}
--
2.10.2
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