libgo: handle linking to NetBSD's versioned symbols

On NetBSD, for backwards compatibility, various libc symbols are
renamed to a symbol with a version suffix. For example, this is the
(abbreviated) definition of sigaction:

    int sigaction(...) __asm__ ("__sigaction14")

This poses a challenge for libgo, which attempts to link sigaction by
way of an "//extern" comment:

    //extern sigaction
    func sigaction(...)

This results in a reference to the deprecated compatibility symbol
"sigaction", rather than the desired "__sigaction14" symbol.

This patch introduces a new "//extern-sysinfo" comment to handle this
situation. The new mklinknames.awk script scans a package for these
comments and outputs a "//go:linkname" directive that links the wrapper
to the correct versioned symbol, as determined by parsing the __asm__
annotation on the function's declaration in gen-sysinfo.go.

For now, only the following packages are scanned by mklinknames.awk:

    os
    os/user
    runtime
    syscall

gotools/:
	* Makefile.am (check-runtime): Add runtime_linknames.go to
	--extrafiles.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/265125

2 files changed, 4 insertions, 4 deletions

diff --git a/gotools/Makefile.am b/gotools/Makefile.am
index 47adf9b..1b8702e 100644
--- a/gotools/Makefile.am
+++ b/gotools/Makefile.am
@@ -241,14 +241,14 @@ check-runtime: go$(EXEEXT) $(noinst_PROGRAMS) check-head check-gccgo check-gcc
 	export LD_LIBRARY_PATH; \
 	GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
 	GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
+	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
 	echo "$(ECHO_ENV) GC='$(abs_builddir)/check-gccgo -fgo-compiling-runtime' GOARCH=$${GOARCH} GOOS=$${GOOS} $(SHELL) $(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} --goos=$${GOOS} --basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime --pkgpath=runtime --pkgfiles='$${files}' $(GOTESTFLAGS) -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > runtime-testlog
 	$(CHECK_ENV) \
 	GC="$${GCCGO} -fgo-compiling-runtime"; \
 	export GC; \
 	GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
 	GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
+	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
 	$(SHELL) $(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} --goos=$${GOOS} --basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime --pkgpath=runtime --pkgfiles="$${files}" $(GOTESTFLAGS) -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v >> runtime-testlog 2>&1 || echo "--- $${fl}: go test runtime (0.00s)" >> runtime-testlog
 	grep '^--- ' runtime-testlog | sed -e 's/^--- \(.*\) ([^)]*)$$/\1/' | sort -k 2
 
diff --git a/gotools/Makefile.in b/gotools/Makefile.in
index 930189a..9292312 100644
--- a/gotools/Makefile.in
+++ b/gotools/Makefile.in
@@ -912,14 +912,14 @@ mostlyclean-local:
 @NATIVE_TRUE@	export LD_LIBRARY_PATH; \
 @NATIVE_TRUE@	GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
 @NATIVE_TRUE@	GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-@NATIVE_TRUE@	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
+@NATIVE_TRUE@	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
 @NATIVE_TRUE@	echo "$(ECHO_ENV) GC='$(abs_builddir)/check-gccgo -fgo-compiling-runtime' GOARCH=$${GOARCH} GOOS=$${GOOS} $(SHELL) $(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} --goos=$${GOOS} --basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime --pkgpath=runtime --pkgfiles='$${files}' $(GOTESTFLAGS) -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v" > runtime-testlog
 @NATIVE_TRUE@	$(CHECK_ENV) \
 @NATIVE_TRUE@	GC="$${GCCGO} -fgo-compiling-runtime"; \
 @NATIVE_TRUE@	export GC; \
 @NATIVE_TRUE@	GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
 @NATIVE_TRUE@	GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-@NATIVE_TRUE@	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
+@NATIVE_TRUE@	files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} --goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime --extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go $(libgodir)/sigtab.go" --tag=libffi`; \
 @NATIVE_TRUE@	$(SHELL) $(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} --goos=$${GOOS} --basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime --pkgpath=runtime --pkgfiles="$${files}" $(GOTESTFLAGS) -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v >> runtime-testlog 2>&1 || echo "--- $${fl}: go test runtime (0.00s)" >> runtime-testlog
 @NATIVE_TRUE@	grep '^--- ' runtime-testlog | sed -e 's/^--- \(.*\) ([^)]*)$$/\1/' | sort -k 2