From 54fe57bc22f7890810bbddae2499eda8d4acfaef Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Thu, 17 Jun 2021 01:12:23 -0700 Subject: [dev.typeparams] cmd/compile: record writer's stack at export data sync points This CL extends the unified export data format's existing sync mechanism to save writer stacks, controlled by the -d=syncframes debug flag. This allows readers to provide more details when reporting desync errors, which should simplify development of the data format and the various reader/writer implementations. For example, CL 328051 updated reader and writer, but missed making a similar change to the linker (fix in CL 328054). Re-reviewing the CL in isolation after the failure, it was not immediately obvious what was going wrong. But the pair of stack traces below identifies exactly what happened: it should have updated linker.relocFuncExt to write out the new sync marker too. ``` data sync error: package "internal/abi", section 6, index 4, offset 536 found UseReloc, written at: /home/mdempsky/wd/go/src/cmd/compile/internal/noder/encoder.go:221: (*encoder).reloc +0x44 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/linker.go:214: (*linker).relocFuncExt +0x580 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/linker.go:233: (*linker).relocTypeExt +0x234 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/linker.go:161: (*linker).relocObj +0x2198 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/linker.go:64: (*linker).relocIdx +0x196 expected ImplicitTypes, reading at: /home/mdempsky/wd/go/src/cmd/compile/internal/noder/reader.go:796: (*reader).implicitTypes +0x36 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/reader.go:810: (*reader).addBody +0x81 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/reader.go:727: (*reader).funcExt +0x542 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/reader.go:651: (*reader).method +0x324 /home/mdempsky/wd/go/src/cmd/compile/internal/noder/reader.go:557: (*pkgReader).objIdx +0x2704 ``` Change-Id: I911193edd2a965f81b7459f15fb613a773584685 Reviewed-on: https://go-review.googlesource.com/c/go/+/328909 Run-TryBot: Matthew Dempsky TryBot-Result: Go Bot Trust: Matthew Dempsky Reviewed-by: Cuong Manh Le Reviewed-by: Robert Griesemer --- src/cmd/compile/internal/base/debug.go | 1 + 1 file changed, 1 insertion(+) (limited to 'src/cmd/compile/internal/base/debug.go') diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go index 824a8baa83..fd42021946 100644 --- a/src/cmd/compile/internal/base/debug.go +++ b/src/cmd/compile/internal/base/debug.go @@ -44,6 +44,7 @@ type DebugFlags struct { Panic int `help:"show all compiler panics"` Slice int `help:"print information about slice compilation"` SoftFloat int `help:"force compiler to emit soft-float code"` + SyncFrames int `help:"how many writer stack frames to include at sync points in unified export data"` TypeAssert int `help:"print information about type assertion inlining"` TypecheckInl int `help:"eager typechecking of inline function bodies"` Unified int `help:"enable unified IR construction"` -- cgit v1.3