cmd/go: permit additional cflags when compiling

In CL 475375 the Go command started to generate the "preferlinkext"
token file for "strange/dangerous" compiler flags. This serves as a hint
to the Go linker whether to call the external linker or not.

Permit compiler flags used by bazel and bazelbuild/rules_go during
compilation of cgo code to not prefer external linking. This restores
the behavior of previous versions of Go.

As a side effect, it also allows these flags to appear
in #cgo directives in source code. We don't know of any cases
where that is actually useful, but it appears to be harmless
and simplifies the implementation of the internal linking change.

Fixes #60865

Change-Id: I176a6a2a2cf36293dd9aed24be928f98fa2fb6d9
GitHub-Last-Rev: 071e915b8e4e6b466e1accbfd2b9b45fc9982a34
GitHub-Pull-Request: golang/go#60868
Reviewed-on: https://go-review.googlesource.com/c/go/+/504335
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>

diff --git a/src/cmd/go/internal/work/security.go b/src/cmd/go/internal/work/security.go
index 270a34e9c7cf7fbd689f85114c6a1d0f87b434d6..88504be6cd6b4123a04c8f34381ff53b95afd56c 100644 (file)
--- a/src/cmd/go/internal/work/security.go
+++ b/src/cmd/go/internal/work/security.go
@@ -59,7 +59,10 @@ var validCompilerFlags = []*lazyregexp.Regexp{
        re(`-f(no-)builtin-[a-zA-Z0-9_]*`),
        re(`-f(no-)?common`),
        re(`-f(no-)?constant-cfstrings`),
+       re(`-fdebug-prefix-map=([^@]+)=([^@]+)`),
        re(`-fdiagnostics-show-note-include-stack`),
+       re(`-ffile-prefix-map=([^@]+)=([^@]+)`),
+       re(`-fno-canonical-system-headers`),
        re(`-f(no-)?eliminate-unused-debug-types`),
        re(`-f(no-)?exceptions`),
        re(`-f(no-)?fast-math`),
@@ -114,6 +117,7 @@ var validCompilerFlags = []*lazyregexp.Regexp{
        re(`-mthumb(-interwork)?`),
        re(`-mthreads`),
        re(`-mwindows`),
+       re(`-no-canonical-prefixes`),
        re(`--param=ssp-buffer-size=[0-9]*`),
        re(`-pedantic(-errors)?`),
        re(`-pipe`),

diff --git a/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt b/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt
index d555278865baf2b3f8c4904e17dd7b604b23614f..6dc30bedb9e9ca127819797dbec8cc307a277ccd 100644 (file)
--- a/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt
+++ b/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt
@@ -55,6 +55,32 @@ stderr preferlinkext
 env CGO_CFLAGS=-fprofile-instr-generate
 go build -x -n -o dummy.exe ./usesInternalCgo
 stderr preferlinkext
+
+# The -fdebug-prefix-map=path is permitted for internal linking.
+env CGO_CFLAGS=-fdebug-prefix-map=/some/sandbox/execroot/workspace=/tmp/new
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+env CGO_CFLAGS=-fdebug-prefix-map=/Users/someone/.cache/bazel/_bazel_someone/3fa7e4650c43657ead684537951f49e2/sandbox/linux-sandbox/10/execroot/rules_go_static=.
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+# The -ffile-prefix-map=path is permitted for internal linking too.
+env CGO_CFLAGS=-ffile-prefix-map=/Users/someone/.cache/bazel/_bazel_someone/3fa7e4650c43657ead684537951f49e2/sandbox/linux-sandbox/10/execroot/rules_go_static/bazel-out/aarch64-fastbuild-ST-b33d65c724e6/bin/external/io_bazel_rules_go/stdlib_=.
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+# Verifying that -fdebug-prefix-map=path, -ffile-prefix-map, -no-canonical-prefixes
+# and -fno-canonical-systemd-headers are permitted for internal linking.
+env CGO_CFLAGS=-fdebug-prefix-map=old=/tmp/new
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+env CGO_CFLAGS=-ffile-prefix-map=/Users/someone/_11233/things=new
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+env CGO_CFLAGS=-no-canonical-prefixes
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+env CGO_CFLAGS=-fno-canonical-system-headers
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
 env CGO_CFLAGS=
 
 [short] skip