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 flag used by the hermetic_cc_toolchain bzlmod.

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 #72842

Change-Id: Ic6de29b535a4e2c0720f383567ea6b3c7ca4f541
Reviewed-on: https://go-review.googlesource.com/c/go/+/657575
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

diff --git a/src/cmd/go/internal/work/security.go b/src/cmd/go/internal/work/security.go
index c3d62ddc23d83a19dafbf9514c56bb4a2459c91d..3b3eba536cb146091082e053df9fad49c4bf917e 100644 (file)
--- a/src/cmd/go/internal/work/security.go
+++ b/src/cmd/go/internal/work/security.go
@@ -90,6 +90,7 @@ var validCompilerFlags = []*lazyregexp.Regexp{
        re(`-f(no-)?use-linker-plugin`), // safe if -B is not used; we don't permit -B
        re(`-f(no-)?visibility-inlines-hidden`),
        re(`-fsanitize=(.+)`),
+       re(`-fsanitize-undefined-strip-path-components=(-)?[0-9]+`),
        re(`-ftemplate-depth-(.+)`),
        re(`-ftls-model=(global-dynamic|local-dynamic|initial-exec|local-exec)`),
        re(`-fvisibility=(.+)`),

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 6dc30bedb9e9ca127819797dbec8cc307a277ccd..b4b2d14b11df337f18623cb977562e6dccef9ae0 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
@@ -56,6 +56,14 @@ env CGO_CFLAGS=-fprofile-instr-generate
 go build -x -n -o dummy.exe ./usesInternalCgo
 stderr preferlinkext
 
+# Trimming file information for the UndefinedBehaviorSanitizer is permitted for internal linking.
+env CGO_CFLAGS=-fsanitize-undefined-strip-path-components=-1
+go build -x -n -o dummy.exe ./usesInternalCgo
+! stderr preferlinkext
+env CGO_CFLAGS=-fsanitize-undefined-strip-path-components=2
+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