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| author | Austin Clements <austin@google.com> | 2017-10-30 16:06:19 -0400 |
|---|---|---|
| committer | Austin Clements <austin@google.com> | 2017-10-31 14:03:10 +0000 |
| commit | 52cf91a5d5d074d8857f1b7be0fe1bc380ed4869 (patch) | |
| tree | b676993892380b3c9cb6377d927ba9872c789f81 /src | |
| parent | 5536180ae72e8745c8a831e03f56a86360d76c52 (diff) | |
| download | go-52cf91a5d5d074d8857f1b7be0fe1bc380ed4869.tar.xz | |
cmd/compile,runtime: update instrumentation comments
The compiler's instrumentation pass has some out-of-date comments
about the write barrier and some confusing comments about
typedslicecopy. Update these comments and add a comment to
typedslicecopy explaining why it's manually instrumented while none of
the other operations are.
Change-Id: I024e5361d53f1c3c122db0c85155368a30cabd6b
Reviewed-on: https://go-review.googlesource.com/74430
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/compile/internal/gc/racewalk.go | 10 | ||||
| -rw-r--r-- | src/runtime/mbarrier.go | 4 |
2 files changed, 11 insertions, 3 deletions
diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go index 2ffd0f96a8..90bfdbf688 100644 --- a/src/cmd/compile/internal/gc/racewalk.go +++ b/src/cmd/compile/internal/gc/racewalk.go @@ -170,10 +170,14 @@ func instrumentnode(np **Node, init *Nodes, wr int, skip int) { case OCALLINTER: instrumentnode(&n.Left, init, 0, 0) - // Instrument dst argument of runtime.writebarrier* calls - // as we do not instrument runtime code. - // typedslicecopy is instrumented in runtime. case OCALLFUNC: + // Note that runtime.typedslicecopy is the only + // assignment-like function call in the AST at this + // point (between walk and SSA); since we don't + // instrument it here, typedslicecopy is manually + // instrumented in runtime. Calls to the write barrier + // and typedmemmove are created later by SSA, so those + // still appear as OAS nodes at this point. instrumentnode(&n.Left, init, 0, 0) case ONOT, diff --git a/src/runtime/mbarrier.go b/src/runtime/mbarrier.go index cb2959fbc3..e28bdb8b8d 100644 --- a/src/runtime/mbarrier.go +++ b/src/runtime/mbarrier.go @@ -326,6 +326,10 @@ func typedslicecopy(typ *_type, dst, src slice) int { dstp := dst.array srcp := src.array + // The compiler emits calls to typedslicecopy before + // instrumentation runs, so unlike the other copying and + // assignment operations, it's not instrumented in the calling + // code and needs its own instrumentation. if raceenabled { callerpc := getcallerpc() pc := funcPC(slicecopy) |