From 0323895cc015aa155013a945caf05f08615ccdcc Mon Sep 17 00:00:00 2001 From: Josh Bleecher Snyder Date: Thu, 30 Mar 2017 11:40:06 -0700 Subject: [PATCH] cmd/compile: catch and report nowritebarrier violations later Prior to this CL, the SSA backend reported violations of the //go:nowritebarrier annotation immediately. This necessitated emitting errors during SSA compilation, which is not compatible with a concurrent backend. Instead, check for such violations later. We already save the data required to do a late check for violations of the //go:nowritebarrierrec annotation. Use the same data, and check //go:nowritebarrier at the same time. One downside to doing this is that now only a single violation will be reported per function. Given that this is for the runtime only, and violations are rare, this seems an acceptable cost. While we are here, remove several 'nerrors != 0' checks that are rendered pointless. Updates #15756 Fixes #19250 (as much as it ever can be) Change-Id: Ia44c4ad5b6fd6f804d9f88d9571cec8d23665cb3 Reviewed-on: https://go-review.googlesource.com/38973 Run-TryBot: Josh Bleecher Snyder TryBot-Result: Gobot Gobot Reviewed-by: Cherry Zhang --- src/cmd/compile/internal/gc/dcl.go | 3 +++ src/cmd/compile/internal/gc/pgen.go | 7 ------- src/cmd/compile/internal/gc/ssa.go | 16 ---------------- src/cmd/compile/internal/ssa/config.go | 3 --- src/cmd/compile/internal/ssa/export_test.go | 1 - src/cmd/compile/internal/ssa/func.go | 1 - src/cmd/compile/internal/ssa/writebarrier.go | 3 --- 7 files changed, 3 insertions(+), 31 deletions(-) diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go index a514aa606a7..b66231ab882 100644 --- a/src/cmd/compile/internal/gc/dcl.go +++ b/src/cmd/compile/internal/gc/dcl.go @@ -1223,6 +1223,9 @@ func checknowritebarrierrec() { visitBottomUp(xtop, func(list []*Node, recursive bool) { // Functions with write barriers have depth 0. for _, n := range list { + if n.Func.WBPos.IsKnown() && n.Func.Pragma&Nowritebarrier != 0 { + yyerrorl(n.Func.WBPos, "write barrier prohibited") + } if n.Func.WBPos.IsKnown() && n.Func.Pragma&Yeswritebarrierrec == 0 { c.best[n] = nowritebarrierrecCall{target: nil, depth: 0, lineno: n.Func.WBPos} } diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go index 02cabc4a025..fdebae763a1 100644 --- a/src/cmd/compile/internal/gc/pgen.go +++ b/src/cmd/compile/internal/gc/pgen.go @@ -269,19 +269,12 @@ func compile(fn *Node) { if instrumenting { instrument(fn) } - if nerrors != 0 { - return - } // From this point, there should be no uses of Curfn. Enforce that. Curfn = nil // Build an SSA backend function. ssafn := buildssa(fn) - if nerrors != 0 { - return - } - pp := newProgs(fn) genssa(ssafn, pp) fieldtrack(pp.Text.From.Sym, fn.Func.FieldTrack) diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go index cbd340974b5..794b8017f1f 100644 --- a/src/cmd/compile/internal/gc/ssa.go +++ b/src/cmd/compile/internal/gc/ssa.go @@ -122,9 +122,6 @@ func buildssa(fn *Node) *ssa.Func { if fn.Func.Pragma&Nosplit != 0 { s.f.NoSplit = true } - if fn.Func.Pragma&Nowritebarrier != 0 { - s.f.NoWB = true - } defer func() { if s.f.WBPos.IsKnown() { fn.Func.WBPos = s.f.WBPos @@ -197,10 +194,6 @@ func buildssa(fn *Node) *ssa.Func { s.popLine() } - if nerrors > 0 { - return nil - } - s.insertPhis() // Don't carry reference this around longer than necessary @@ -208,10 +201,6 @@ func buildssa(fn *Node) *ssa.Func { // Main call to ssa package to compile function ssa.Compile(s.f) - if nerrors > 0 { - return nil - } - return s.f } @@ -4884,11 +4873,6 @@ func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...interface{}) { Fatalf(msg, args...) } -// Error reports a compiler error but keep going. -func (e *ssafn) Error(pos src.XPos, msg string, args ...interface{}) { - yyerrorl(pos, msg, args...) -} - // Warnl reports a "warning", which is usually flag-triggered // logging output for the benefit of tests. func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...interface{}) { diff --git a/src/cmd/compile/internal/ssa/config.go b/src/cmd/compile/internal/ssa/config.go index 912fb16d8b5..96a4c2b8ae7 100644 --- a/src/cmd/compile/internal/ssa/config.go +++ b/src/cmd/compile/internal/ssa/config.go @@ -80,9 +80,6 @@ type Logger interface { // Fatal reports a compiler error and exits. Fatalf(pos src.XPos, msg string, args ...interface{}) - // Error reports a compiler error but keep going. - Error(pos src.XPos, msg string, args ...interface{}) - // Warnl writes compiler messages in the form expected by "errorcheck" tests Warnl(pos src.XPos, fmt_ string, args ...interface{}) diff --git a/src/cmd/compile/internal/ssa/export_test.go b/src/cmd/compile/internal/ssa/export_test.go index c26df1b9645..f7a80a8c00b 100644 --- a/src/cmd/compile/internal/ssa/export_test.go +++ b/src/cmd/compile/internal/ssa/export_test.go @@ -124,7 +124,6 @@ func (d DummyFrontend) Logf(msg string, args ...interface{}) { d.t.Logf(msg, arg func (d DummyFrontend) Log() bool { return true } func (d DummyFrontend) Fatalf(_ src.XPos, msg string, args ...interface{}) { d.t.Fatalf(msg, args...) } -func (d DummyFrontend) Error(_ src.XPos, msg string, args ...interface{}) { d.t.Errorf(msg, args...) } func (d DummyFrontend) Warnl(_ src.XPos, msg string, args ...interface{}) { d.t.Logf(msg, args...) } func (d DummyFrontend) Debug_checknil() bool { return false } func (d DummyFrontend) Debug_wb() bool { return false } diff --git a/src/cmd/compile/internal/ssa/func.go b/src/cmd/compile/internal/ssa/func.go index 17860957cff..5093d0e7fc0 100644 --- a/src/cmd/compile/internal/ssa/func.go +++ b/src/cmd/compile/internal/ssa/func.go @@ -37,7 +37,6 @@ type Func struct { scheduled bool // Values in Blocks are in final order NoSplit bool // true if function is marked as nosplit. Used by schedule check pass. - NoWB bool // write barrier is not allowed WBPos src.XPos // line number of first write barrier // when register allocation is done, maps value ids to locations diff --git a/src/cmd/compile/internal/ssa/writebarrier.go b/src/cmd/compile/internal/ssa/writebarrier.go index 35be9a09d7d..1b6e51c674e 100644 --- a/src/cmd/compile/internal/ssa/writebarrier.go +++ b/src/cmd/compile/internal/ssa/writebarrier.go @@ -208,9 +208,6 @@ func writebarrier(f *Func) { memElse.Aux = w.Aux } - if f.NoWB { - f.fe.Error(pos, "write barrier prohibited") - } if !f.WBPos.IsKnown() { f.WBPos = pos }