## Compiler {#compiler}

## Assembler {#assembler}

env CGO_LDFLAGS=-Wno-such-warning -Wno-unknown-warning-option
cd ../ok
go build

# Build a main program that actually uses LDFLAGS.
cd ..
go build -ldflags=-v

# Because we passed -v the Go linker should print the external linker
# command which should include the flag we passed in CGO_LDFLAGS.
stderr no-such-warning

-- go.mod --
module ldflag

-- bad/bad.go --
package bad

imported normally and vendored by the standard library.

Vendored packages are internally renamed with a "vendor/" prefix
to preserve the invariant that all packages have distinct paths.
This is necessary to avoid compiler and linker conflicts. Adding
a "vendor/" prefix also maintains the invariant that standard
library packages begin with a dotless path element.

The module requirements of std and cmd do not influence version

# Building a trivial main package should run the compiler and linker the first time.
go build -x -gcflags=-m -ldflags='-v -w' main.go
stderr 'compile( |\.exe"?)'
stderr 'main.go:2.* can inline main' # from compiler
stderr 'link(\.exe"?)? -'
stderr '\d+ symbols' # from linker

# ... but not the second, even though it still prints the compiler and linker output.
go build -x -gcflags=-m -ldflags='-v -w' main.go

# When generating _cgo_import.go for package c fails, an ordinary
# external link should still work. But an internal link is expected
# to fail, because the failure to create _cgo_import.go should cause
# the linker to report an inability to internally link.

[short] skip
[!cgo] skip
[!exec:ar] skip

cc -c -o a/b.syso b/b.c
cc -c -o b/lib.o b/lib.c
exec ar rc a/libb.a b/lib.o
go build

## Assembler {#assembler}

## Linker {#linker}

<!-- go.dev/issue/67401, CL 585556, CL 587220, and many more -->
The linker now disallows using a `//go:linkname` directive to refer to
internal symbols in the standard library (including the runtime) that
are not marked with `//go:linkname` on their definitions.
Similarly, the linker disallows references to such symbols from assembly
code.

env GO111MODULE=off

# check for linker name in error message about linker crash
[!compiler:gc] skip
! go build -ldflags=-crash_for_testing x.go
stderr [\\/]tool[\\/].*[\\/]link

-- x.go --

[short] skip

# In the remaining tests below we do actual builds (without -n) to
# verify that the Go linker is going the right thing in addition to the
# Go command. Here the idea is to pass "-tmpdir" to the linker, then
# check after the link is done for the presence of the file
# <tmpdir>/go.o, which the Go linker creates prior to kicking off the
# external linker.

mkdir tmp1
mkdir tmp2
mkdir tmp3
mkdir tmp4
mkdir tmp5

# Issue #46092
# go list -find should always return a package with an empty Deps list

# The linker loads implicit dependencies
go list -find -f {{.Deps}} ./cmd
stdout '\[\]'

# Cgo translation may add imports of "unsafe", "runtime/cgo" and "syscall"
go list -find -f {{.Deps}} ./cgo
stdout '\[\]'

# SWIG adds imports of some standard packages
go list -find -f {{.Deps}} ./swig
stdout '\[\]'

-- go.mod --
module listfind

# Test case for issue 47993, in which the linker crashes
# on a bad input instead of issuing an error and exiting.

# This test requires external linking, so use cgo as a proxy 
[!cgo] skip

! go build -ldflags='-linkmode=external' .
! stderr 'panic'
stderr '^.*undefined symbol in relocation.*'

-- go.mod --

module issue47993

go 1.16

-- main.go --

package main

type M struct {
	b bool
}