## Compiler {#compiler}

## Assembler {#assembler}

## Compiler {#compiler}

## Assembler {#assembler}

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

package cgotest

// Test that we have no more than one build ID.  In the past we used
// to generate a separate build ID for each package using cgo, and the
// linker concatenated them all.  We don't want that--we only want
// one.

import (
	"bytes"
	"debug/elf"
	"os"
	"testing"
)

func testBuildID(t *testing.T) {
	f, err := elf.Open("/proc/self/exe")

the host linker. The default value for the host linker is $CC, split
into fields, or else "gcc". The specific host linker command line can
be overridden using command line flags: cmd/link -extld=clang
-extldflags='-ggdb -O3'. If any package in a build includes a .cc or
other file compiled by the C++ compiler, the go tool will use the
-extld option to set the host linker to the C++ compiler.

package cgotest

import "testing"

// If gcc is used, and linking internally, __mulsc3 and __muldc3
// will be linked in from libgcc which make several R_PPC64_TOC16_DS
// relocations which may not be resolvable with the internal linker.
func test8694(t *testing.T) { t.Skip("not supported on ppc64/ppc64le with internal linking") }

are reserved by the compiler and linker.
</p>

<p>
<code>R10</code> points to the <code>g</code> (goroutine) structure.
Within assembler source code, this pointer must be referred to as <code>g</code>;
the name <code>R10</code> is not recognized.
</p>

<p>
To make it easier for people and compilers to write assembly, the ARM linker

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build cgo && !windows

// Issue 29563: internal linker fails on duplicate weak symbols.
// No runtime test; just make sure it compiles.

package cgotest

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

      --enable-initfini-array \
      --enable-languages="c,c++" \
      --enable-linker-build-id \
      --enable-plugin \
      --enable-shared \
      --enable-threads=posix \
      --with-default-libstdcxx-abi=${LIBSTDCXX_ABI} \
      --with-gcc-major-version-only \
      --with-linker-hash-style="gnu" \
      && \
      make -j$(nproc) && \
      make install

		if f == nil {
			continue
		}
		fname := f.Name()
		switch fname {
		case "goCallback":
			// TODO(qmuntal): investigate why this function doesn't appear
			// when using the external linker.
			continue
		}
		// In module mode, this package has a fully-qualified import path.
		// Remove it if present.
		fname = strings.TrimPrefix(fname, "cmd/cgo/internal/")
		if !strings.HasPrefix(fname, "test.") {