diff options
| author | Than McIntosh <thanm@google.com> | 2021-05-04 16:18:56 -0400 |
|---|---|---|
| committer | Than McIntosh <thanm@google.com> | 2021-05-05 01:47:58 +0000 |
| commit | 66ce8aa88d144338868b0d3ab8c895608a460750 (patch) | |
| tree | 903f4f6119631b072a83fc71ecaa2fbf74c1d0e9 /src/cmd | |
| parent | 4df662fb373480b5055e645120558bb536fae42c (diff) | |
| download | go-66ce8aa88d144338868b0d3ab8c895608a460750.tar.gz go-66ce8aa88d144338868b0d3ab8c895608a460750.zip | |
cmd/compile: handle degenerate entry blocks in -N debug gen
The code that created DWARF debug var locations for input parameters
in the non-optimized case for regabi was not doing the right thing for
degenerate functions with infinite loops. Detect these cases and don't
try to emit the normal location data.
Fixes #45948.
Change-Id: I2717fc4bac2e03d5d850a6ec8a09ed05fed0c896
Reviewed-on: https://go-review.googlesource.com/c/go/+/316752
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Diffstat (limited to 'src/cmd')
| -rw-r--r-- | src/cmd/compile/internal/ssa/debug.go | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go index ee522f41ef..2f379c9e2c 100644 --- a/src/cmd/compile/internal/ssa/debug.go +++ b/src/cmd/compile/internal/ssa/debug.go @@ -1362,9 +1362,6 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta // Locate the value corresponding to the last spill of // an input register. afterPrologVal := locatePrologEnd(f) - if afterPrologVal == ID(-1) { - panic(fmt.Sprintf("internal error: f=%s: can't locate after prolog value", f.Name)) - } // Walk the input params again and process the register-resident elements. pidx := 0 @@ -1381,6 +1378,15 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta slid := len(fd.VarSlots) fd.VarSlots = append(fd.VarSlots, []SlotID{SlotID(slid)}) + if afterPrologVal == ID(-1) { + // This can happen for degenerate functions with infinite + // loops such as that in issue 45948. In such cases, leave + // the var/slot set up for the param, but don't try to + // emit a location list. + pidx++ + continue + } + // Param is arriving in one or more registers. We need a 2-element // location expression for it. First entry in location list // will correspond to lifetime in input registers. |