diff options
| author | Austin Clements <austin@google.com> | 2023-08-16 12:30:10 -0400 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2023-08-20 17:52:59 +0000 |
| commit | e094e80f65f77bf83e2962dc5150915711f2166d (patch) | |
| tree | 6baae8b2b93dbbe752a0699e5c79193b7d79594a /src/runtime | |
| parent | 9ac6b00e79312e5ad4665acc063ac7b77becddf8 (diff) | |
| download | go-e094e80f65f77bf83e2962dc5150915711f2166d.tar.xz | |
runtime: add self-check mode to cache in pcvalue
This would have helped with debugging the failures caused by CL 515276.
Change-Id: Id641949d8bcd763de7f93778ad9bd3fdde95dcb2
Reviewed-on: https://go-review.googlesource.com/c/go/+/520062
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/symtab.go | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go index ff5f5f7f0e..d828c37a75 100644 --- a/src/runtime/symtab.go +++ b/src/runtime/symtab.go @@ -844,6 +844,10 @@ func pcvalueCacheKey(targetpc uintptr) uintptr { // Returns the PCData value, and the PC where this value starts. func pcvalue(f funcInfo, off uint32, targetpc uintptr, cache *pcvalueCache, strict bool) (int32, uintptr) { + // If true, when we get a cache hit, still look up the data and make sure it + // matches the cached contents. + const debugCheckCache = false + if off == 0 { return -1, 0 } @@ -854,6 +858,8 @@ func pcvalue(f funcInfo, off uint32, targetpc uintptr, cache *pcvalueCache, stri // This cache is small enough that full associativity is // cheaper than doing the hashing for a less associative // cache. + var checkVal int32 + var checkPC uintptr if cache != nil { x := pcvalueCacheKey(targetpc) for i := range cache.entries[x] { @@ -864,7 +870,12 @@ func pcvalue(f funcInfo, off uint32, targetpc uintptr, cache *pcvalueCache, stri // fail in the first clause. ent := &cache.entries[x][i] if ent.off == off && ent.targetpc == targetpc { - return ent.val, ent.valPC + if debugCheckCache { + checkVal, checkPC = ent.val, ent.valPC + break + } else { + return ent.val, ent.valPC + } } } } @@ -894,7 +905,12 @@ func pcvalue(f funcInfo, off uint32, targetpc uintptr, cache *pcvalueCache, stri // larger than the cache. // Put the new element at the beginning, // since it is the most likely to be newly used. - if cache != nil { + if debugCheckCache && checkPC != 0 { + if checkVal != val || checkPC != prevpc { + print("runtime: table value ", val, "@", prevpc, " != cache value ", checkVal, "@", checkPC, " at PC ", targetpc, " off ", off, "\n") + throw("bad pcvalue cache") + } + } else if cache != nil { x := pcvalueCacheKey(targetpc) e := &cache.entries[x] ci := fastrandn(uint32(len(cache.entries[x]))) |