Repository: go
Issue: runtime: debugCheckBP = true crashes compiler compilation on Windows
Labels: OS-Windows,NeedsInvestigation,compiler/runtime

Using 8cd75f3da094931c59636b85a87b4f680a208799 (and also 1.15.3) with enabling `debugBP = true` it crashes the compiler compilation on Windows. On Linux, it compiles fine.

Reporting to ensure that this isn't an indication of a bug somewhere.

Here's the line I changed:
https://github.com/golang/go/blob/28e549dec3954b36d0c83442be913d8709d7e5ae/src/runtime/stack.go#L119

Crash:
```
c:\Go.tip\src>make.bat
Building Go cmd/dist using C:\Go\
Building Go toolchain1 using C:\Go\.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
runtime: found invalid top frame pointer
bp=0xc0009d53d8 min=0xc00080e000 max=0xc000810000
fatal error: bad top frame pointer

runtime stack:
runtime.throw(0x85fbcf, 0x15)
        c:/Go.tip/src/runtime/panic.go:1121 +0x79
runtime.adjustctxt(0xc000914780, 0x298dfc28)
        c:/Go.tip/src/runtime/stack.go:727 +0x168
runtime.copystack(0xc000914780, 0x4000)
        c:/Go.tip/src/runtime/stack.go:894 +0x1a8
runtime.newstack()
        c:/Go.tip/src/runtime/stack.go:1078 +0x2b6
runtime.morestack()
        c:/Go.tip/src/runtime/asm_amd64.s:449 +0x97

goroutine 158 [copystack]:
runtime.gcMarkDone()
        c:/Go.tip/src/runtime/mgc.go:1444 +0x32c fp=0xc00080f388 sp=0xc00080f380 pc=0x41d38c
runtime.gcAssistAlloc(0xc000914780)
        c:/Go.tip/src/runtime/mgcmark.go:455 +0x225 fp=0xc00080f3e8 sp=0xc00080f388 pc=0x4201a5
runtime.mallocgc(0x60, 0x80dfa0, 0x1, 0xc000b3e000)
        c:/Go.tip/src/runtime/malloc.go:959 +0xa9c fp=0xc00080f488 sp=0xc00080f3e8 pc=0x40e4bc
runtime.growslice(0x80dfa0, 0xc000b3e000, 0x2, 0x2, 0x3, 0x0, 0x1, 0x2)
        c:/Go.tip/src/runtime/slice.go:230 +0x209 fp=0xc00080f4f0 sp=0xc00080f488 pc=0x44cac9
go/build.(*Context).Import(0xad2e60, 0x856278, 0x1, 0xc0008c60a8, 0x13, 0x0, 0xc000000008, 0xc00040dc78, 0xc000a06d58)
        c:/Go.tip/src/go/build/build.go:917 +0x279c fp=0xc00080fbc8 sp=0xc00080f4f0 pc=0x5a641c
go/build.(*Context).ImportDir(...)
        c:/Go.tip/src/go/build/build.go:458
cmd/go/internal/load.loadPackageData.func2(0xad2560, 0x7df1c0)
        c:/Go.tip/src/cmd/go/internal/load/pkg.go:795 +0x5e5 fp=0xc00080fca8 sp=0xc00080fbc8 pc=0x6d6245
cmd/go/internal/par.(*Cache).Do(0xad2560, 0x7df1c0, 0xc0007e6050, 0xc00040dea8, 0x818fe0, 0xc000668090)
        c:/Go.tip/src/cmd/go/internal/par/work.go:128 +0xff fp=0xc00080fd08 sp=0xc00080fca8 pc=0x5f947f
cmd/go/internal/load.loadPackageData(0xc000332287, 0x5, 0xc00012c091, 0x5, 0xc0003d6060, 0x13, 0xc00000c410, 0x9, 0xc00008c201, 0x1, ...)
        c:/Go.tip/src/cmd/go/internal/load/pkg.go:787 +0x4d7 fp=0xc00080ff20 sp=0xc00080fd08 pc=0x6c4077
cmd/go/internal/load.(*preload).preloadImports.func1(0xc000172000, 0x1, 0xc0007ac5c0, 0xc000332287, 0x5)
        c:/Go.tip/src/cmd/go/internal/load/pkg.go:945 +0xa6 fp=0xc00080ffb8 sp=0xc00080ff20 pc=0x6d6506
runtime.goexit()
        c:/Go.tip/src/runtime/asm_amd64.s:1376 +0x1 fp=0xc00080ffc0 sp=0xc00080ffb8 pc=0x46b4a1
created by cmd/go/internal/load.(*preload).preloadImports
        c:/Go.tip/src/cmd/go/internal/load/pkg.go:944 +0x19e

...
```