// correctly, and sometimes they break. This variable is a
// backup: it depends only on old C style static linking rules.

package cgo

import _ "unsafe" // for go:linkname

//go:linkname _iscgo runtime.iscgo

)

// iscgo is set to true by the runtime/cgo package
//
// iscgo should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/ebitengine/purego
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname iscgo
var iscgo bool

	}
}

func testGoExec(t *testing.T, iscgo, isexternallinker bool) {
	t.Parallel()
	tmpdir, err := os.MkdirTemp("", "TestGoExec")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(tmpdir)

	src := filepath.Join(tmpdir, "a.go")
	file, err := os.Create(src)
	if err != nil {
		t.Fatal(err)
	}
	err = template.Must(template.New("main").Parse(testexec)).Execute(file, iscgo)
	if e := file.Close(); err == nil {

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"

// If !iscgo, this is a no-op.
//
// NOTE: mcall() assumes this clobbers only R30 (REGTMP).
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
	MOVB	runtime·iscgo(SB), R30
	BEQ	R30, nocgo

	MOVV	g, runtime·tls_g(SB)

nocgo:

		return true, fmt.Sprintf("%s/%s requires external linking", buildcfg.GOOS, buildcfg.GOARCH)
	}

	if *flagMsan {
		return true, "msan"
	}

	if *flagAsan {
		return true, "asan"
	}

	if iscgo && platform.MustLinkExternal(buildcfg.GOOS, buildcfg.GOARCH, true) {
		return true, buildcfg.GOARCH + " does not support internal cgo"
	}

	// Some build modes require work the internal linker cannot do (yet).

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"

// If !iscgo, this is a no-op.
//
// NOTE: mcall() assumes this clobbers only X31 (REG_TMP).
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
#ifndef GOOS_openbsd
	MOVB	runtime·iscgo(SB), X31
	BEQZ	X31, nocgo
#endif

// license that can be found in the LICENSE file.

//go:build mips64 || mips64le

#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"

// If !iscgo, this is a no-op.
//
// NOTE: mcall() assumes this clobbers only R23 (REGTMP).
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
	MOVB	runtime·iscgo(SB), R23
	BEQ	R23, nocgo

	MOVV	R3, R23	// save R3

// license that can be found in the LICENSE file.

//go:build mips || mipsle

#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"

// If !iscgo, this is a no-op.
// NOTE: gogo assumes load_g only clobers g (R30) and REGTMP (R23)
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
	MOVB	runtime·iscgo(SB), R23
	BEQ	R23, nocgo

	MOVW	R3, R23

	var sa sigactiont
	sa.sa_flags = _SA_SIGINFO | _SA_ONSTACK | _SA_RESTART
	sa.sa_mask = sigset_all
	if fn == abi.FuncPCABIInternal(sighandler) { // abi.FuncPCABIInternal(sighandler) matches the callers in signal_unix.go
		if iscgo {
			fn = abi.FuncPCABI0(cgoSigtramp)
		} else {
			fn = abi.FuncPCABI0(sigtramp)
		}
	}
	sa.sa_handler = fn
	sigaction(i, &sa, nil)

// this might well result in another SIGSEGV.

// save_g saves the g register into pthread-provided
// thread-local memory, so that we can call externally compiled
// ppc64 code that will overwrite this register.
//
// If !iscgo, this is a no-op.
//
// NOTE: setg_gcc<> assume this clobbers only R31.
TEXT runtime·save_g(SB),NOSPLIT|NOFRAME,$0-0
#ifndef GOOS_aix
#ifndef GOOS_openbsd
	MOVBZ	runtime·iscgo(SB), R31
	CMP	R31, $0
	BEQ	nocgo