Add a script to generate the ChaCha ARM asm.

Obviously I shouldn't be doing this by hand each time.

Change-Id: I64e3f5ede5c47eddbff3b18172a95becc681b486
Reviewed-on: https://boringssl-review.googlesource.com/3170
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>

crypto/chacha/chacha_vec_arm.S

@@ -17,9 +17,10 @@
 # were to be compiled with the needed flags to build chacha_vec.c, then it
 # wouldn't be possible to run on non-NEON systems.
 #
-# This file was generated by:
+# This file was generated by chacha_vec_arm_generate.go using the following
+# compiler command:
 #
-#     /opt/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc -O3 -mcpu=cortex-a8 -mfpu=neon -S chacha_vec.c -DASM_GEN -I ../../include -fpic -o chacha_vec_arm.S
+#     /opt/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc -O3 -mcpu=cortex-a8 -mfpu=neon -fpic -DASM_GEN -I ../../include -S chacha_vec.c -o -
 
 #if !defined(OPENSSL_NO_ASM)
 

crypto/chacha/chacha_vec_arm_generate.go

@@ -0,0 +1,148 @@
+// Copyright (c) 2014, Google Inc.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// This package generates chacha_vec_arm.S from chacha_vec.c.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+const defaultCompiler = "/opt/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc"
+
+func main() {
+	compiler := defaultCompiler
+	if len(os.Args) > 1 {
+		compiler = os.Args[1]
+	}
+
+	args := []string{
+		"-O3",
+		"-mcpu=cortex-a8",
+		"-mfpu=neon",
+		"-fpic",
+		"-DASM_GEN",
+		"-I", "../../include",
+		"-S", "chacha_vec.c",
+		"-o", "-",
+	}
+
+	output, err := os.OpenFile("chacha_vec_arm.S", os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+	if err != nil {
+		panic(err)
+	}
+	defer output.Close()
+
+	output.WriteString(preamble)
+	output.WriteString(compiler)
+	output.WriteString(" ")
+	output.WriteString(strings.Join(args, " "))
+	output.WriteString("\n\n#if !defined(OPENSSL_NO_ASM)\n\n")
+
+	cmd := exec.Command(compiler, args...)
+	cmd.Stderr = os.Stderr
+	asm, err := cmd.StdoutPipe()
+	if err != nil {
+		panic(err)
+	}
+	if err := cmd.Start(); err != nil {
+		panic(err)
+	}
+
+	attr28 := []byte(".eabi_attribute 28,")
+	globalDirective := []byte(".global\t")
+	newLine := []byte("\n")
+	attr28Handled := false
+
+	scanner := bufio.NewScanner(asm)
+	for scanner.Scan() {
+		line := scanner.Bytes()
+
+		if bytes.Contains(line, attr28) {
+			output.WriteString(attr28Block)
+			attr28Handled = true
+			continue
+		}
+
+		output.Write(line)
+		output.Write(newLine)
+
+		if i := bytes.Index(line, globalDirective); i >= 0 {
+			output.Write(line[:i])
+			output.WriteString(".hidden\t")
+			output.Write(line[i+len(globalDirective):])
+			output.Write(newLine)
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+
+	if !attr28Handled {
+		panic("EABI attribute 28 not seen in processing")
+	}
+
+	if err := cmd.Wait(); err != nil {
+		panic(err)
+	}
+
+	output.WriteString(trailer)
+}
+
+const preamble = `# Copyright (c) 2014, Google Inc.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+# This file contains a pre-compiled version of chacha_vec.c for ARM. This is
+# needed to support switching on NEON code at runtime. If the whole of OpenSSL
+# were to be compiled with the needed flags to build chacha_vec.c, then it
+# wouldn't be possible to run on non-NEON systems.
+#
+# This file was generated by chacha_vec_arm_generate.go using the following
+# compiler command:
+#
+#     `
+
+const attr28Block = `
+# EABI attribute 28 sets whether VFP register arguments were used to build this
+# file. If object files are inconsistent on this point, the linker will refuse
+# to link them. Thus we report whatever the compiler expects since we don't use
+# VFP arguments.
+
+#if defined(__ARM_PCS_VFP)
+	.eabi_attribute 28, 1
+#else
+	.eabi_attribute 28, 0
+#endif
+
+`
+
+const trailer = `
+#endif  /* !OPENSSL_NO_ASM */
+`