internal/bytealg, internal/cpu, internal/poll: portability fixes

In internal/bytealg correct a +build tag to never build indexbyte_generic.go
    for the gofrontend, where we always use indexbyte_native.go.
    
    For internal/cpu let the Makefile define CacheLineSize using goarch.sh,
    rather than trying to enumerate all the possibilities in cpu_ARCH.go files.
    
    In internal/poll call the C fcntl function rather than using SYS_FCNTL.
    Change mksysinfo.sh to ensure that F_GETPIPE_SZ is always defined,
    and check that in internal/poll.
    
    Reviewed-on: https://go-review.googlesource.com/137256

From-SVN: r264572

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-1dbc5b805a1665079008d1ce341991c3554c1eeb
+652fbfb7acfd81ceffe28e20984464aa7bb6024d
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/Makefile.am

@@ -532,6 +532,14 @@ s-version: Makefile
 	$(SHELL) $(srcdir)/mvifdiff.sh version.go.tmp version.go
 	$(STAMP) $@
 
+cpugen.go: s-cpu; @true
+s-cpu: Makefile
+	rm -f cpugen.go.tmp
+	echo "package cpu" > cpugen.go.tmp
+	echo "const CacheLineSize = `$(SHELL) $(srcdir)/goarch.sh $(GOARCH) cachelinesize`" >> cpugen.go.tmp
+	$(SHELL) $(srcdir)/mvifdiff.sh cpugen.go.tmp cpugen.go
+	$(STAMP) $@
+
 objabi.go: s-objabi; @true
 s-objabi: Makefile
 	rm -f objabi.go.tmp
@@ -963,6 +971,9 @@ runtime_pprof_check_GOCFLAGS = -static-libgo -fno-inline
 extra_go_files_runtime_internal_sys = version.go
 runtime/internal/sys.lo.dep: $(extra_go_files_runtime_internal_sys)
 
+extra_go_files_internal_cpu = cpugen.go
+internal/cpu.lo.dep: $(extra_go_files_internal_cpu)
+
 extra_go_files_internal_goroot = zstdpkglist.go
 internal/goroot.lo.dep: $(extra_go_files_internal_goroot)
 

libgo/Makefile.in

@@ -1002,6 +1002,7 @@ runtime_internal_sys_lo_check_GOCFLAGS = -fgo-compiling-runtime
 # Also use -fno-inline to get better results from the memory profiler.
 runtime_pprof_check_GOCFLAGS = -static-libgo -fno-inline
 extra_go_files_runtime_internal_sys = version.go
+extra_go_files_internal_cpu = cpugen.go
 extra_go_files_internal_goroot = zstdpkglist.go
 extra_go_files_go_types = gccgosizes.go
 extra_go_files_cmd_internal_objabi = objabi.go
@@ -2759,6 +2760,14 @@ s-version: Makefile
 	$(SHELL) $(srcdir)/mvifdiff.sh version.go.tmp version.go
 	$(STAMP) $@
 
+cpugen.go: s-cpu; @true
+s-cpu: Makefile
+	rm -f cpugen.go.tmp
+	echo "package cpu" > cpugen.go.tmp
+	echo "const CacheLineSize = `$(SHELL) $(srcdir)/goarch.sh $(GOARCH) cachelinesize`" >> cpugen.go.tmp
+	$(SHELL) $(srcdir)/mvifdiff.sh cpugen.go.tmp cpugen.go
+	$(STAMP) $@
+
 objabi.go: s-objabi; @true
 s-objabi: Makefile
 	rm -f objabi.go.tmp
@@ -2957,6 +2966,7 @@ $(foreach package,$(GOTOOL_PACKAGES),$(eval $(call PACKAGE_template,$(package)))
 runtime.lo.dep: $(extra_go_files_runtime)
 syscall.lo.dep: $(extra_go_files_syscall)
 runtime/internal/sys.lo.dep: $(extra_go_files_runtime_internal_sys)
+internal/cpu.lo.dep: $(extra_go_files_internal_cpu)
 internal/goroot.lo.dep: $(extra_go_files_internal_goroot)
 go/types.lo.dep: $(extra_go_files_go_types)
 cmd/internal/objabi.lo.dep: $(extra_go_files_cmd_internal_objabi)

libgo/go/internal/bytealg/indexbyte_generic.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +ignore_for_gccgo
+// +build ignore_for_gccgo
 // +build !386,!amd64,!amd64p32,!s390x,!arm,!arm64,!ppc64,!ppc64le,!mips,!mipsle,!mips64,!mips64le,!wasm
 
 package bytealg

libgo/go/internal/cpu/cpu_arm.go

@@ -1,7 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 32

libgo/go/internal/cpu/cpu_arm64.go

@@ -4,8 +4,6 @@
 
 package cpu
 
-const CacheLineSize = 64
-
 // arm64 doesn't have a 'cpuid' equivalent, so we rely on HWCAP/HWCAP2.
 // These are initialized by archauxv in runtime/os_linux_arm64.go.
 // These should not be changed after they are initialized.

libgo/go/internal/cpu/cpu_mips.go

@@ -1,7 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 32

libgo/go/internal/cpu/cpu_mips64.go

@@ -1,7 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 32

libgo/go/internal/cpu/cpu_mips64le.go

@@ -1,7 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 32

libgo/go/internal/cpu/cpu_mipsle.go

@@ -1,7 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 32

libgo/go/internal/cpu/cpu_ppc64x.go

@@ -6,8 +6,6 @@
 
 package cpu
 
-const CacheLineSize = 128
-
 // ppc64x doesn't have a 'cpuid' equivalent, so we rely on HWCAP/HWCAP2.
 // These are initialized by archauxv in runtime/os_linux_ppc64x.go.
 // These should not be changed after they are initialized.

libgo/go/internal/cpu/cpu_s390x.go

@@ -4,8 +4,6 @@
 
 package cpu
 
-const CacheLineSize = 256
-
 // bitIsSet reports whether the bit at index is set. The bit index
 // is in big endian order, so bit index 0 is the leftmost bit.
 func bitIsSet(bits []uint64, index uint) bool {

libgo/go/internal/cpu/cpu_wasm.go

@@ -1,7 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cpu
-
-const CacheLineSize = 64

libgo/go/internal/cpu/cpu_x86.go

@@ -6,8 +6,6 @@
 
 package cpu
 
-const CacheLineSize = 64
-
 // cpuid is implemented in cpu_x86.s.
 func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
 

libgo/go/internal/poll/splice_linux.go

@@ -162,10 +162,15 @@ func newTempPipe() (prfd, pwfd int, sc string, err error) {
 		defer atomic.StorePointer(&disableSplice, unsafe.Pointer(p))
 
 		// F_GETPIPE_SZ was added in 2.6.35, which does not have the -EAGAIN bug.
-		if _, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fds[0]), syscall.F_GETPIPE_SZ, 0); errno != 0 {
+		if syscall.F_GETPIPE_SZ == 0 {
 			*p = true
 			destroyTempPipe(fds[0], fds[1])
-			return -1, -1, "fcntl", errno
+			return -1, -1, "fcntl", syscall.EINVAL
+		}
+		if _, errno := fcntl(uintptr(fds[0]), syscall.F_GETPIPE_SZ, 0); errno != 0 {
+			*p = true
+			destroyTempPipe(fds[0], fds[1])
+			return -1, -1, "fcntl", syscall.Errno(errno)
 		}
 	}
 

libgo/mksysinfo.sh

@@ -73,6 +73,11 @@ if ! grep '^const F_DUPFD_CLOEXEC' ${OUT} >/dev/null 2>&1; then
   echo "const F_DUPFD_CLOEXEC = 0" >> ${OUT}
 fi
 
+# The internal/poll package requires F_GETPIPE_SZ to be defined.
+if ! grep '^const F_GETPIPE_SZ' ${OUT} >/dev/null 2>&1; then
+  echo "const F_GETPIPE_SZ = 0" >> ${OUT}
+fi
+
 # AIX 7.1 is a 64 bits value for _FCLOEXEC (referenced by O_CLOEXEC)
 # which leads to a constant overflow when using O_CLOEXEC in some
 # go code. Issue wan not present in 6.1 (no O_CLOEXEC) and is no