From d85699eb7d90571b8c39b86774e4ac98058d56f0 Mon Sep 17 00:00:00 2001
From: Joseph Huber <jhuber6@vols.utk.edu>
Date: Tue, 22 Nov 2022 14:59:13 -0600
Subject: [PATCH] [libc] Move strdup implementation to a new header

The `strdup` family of functions rely on `malloc` to be implemented.
Its presence in the `string_utils.h` header meant that compiling many of
the string functions relied on `malloc` being implementated as well.
This patch simply moves the implementation into a new file to avoid
including `stdlib.h` from the other string functions. This was a barrier
for compiling string functions for the GPU where there is no malloc
currently.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D138607
---
 libc/src/string/CMakeLists.txt            |  9 ++++++++
 libc/src/string/allocating_string_utils.h | 37 +++++++++++++++++++++++++++++++
 libc/src/string/strdup.cpp                |  2 +-
 libc/src/string/string_utils.h            | 17 +++++---------
 libc/src/unistd/linux/getcwd.cpp          |  2 +-
 5 files changed, 53 insertions(+), 14 deletions(-)
 create mode 100644 libc/src/string/allocating_string_utils.h

diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
index 9e8287f..2c960af 100644
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -11,6 +11,15 @@ add_header_library(
     .memory_utils.bzero_implementation
 )
 
+add_header_library(
+  allocating_string_utils
+  HDRS
+    allocating_string_utils.h
+  DEPENDS
+    libc.include.stdlib
+    .memory_utils.memcpy_implementation
+)
+
 add_entrypoint_object(
   memccpy
   SRCS
diff --git a/libc/src/string/allocating_string_utils.h b/libc/src/string/allocating_string_utils.h
new file mode 100644
index 0000000..3220400
--- /dev/null
+++ b/libc/src/string/allocating_string_utils.h
@@ -0,0 +1,37 @@
+//===-- Allocating string utils ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LIBC_SRC_STRING_ALLOCATING_STRING_UTILS_H
+#define LIBC_SRC_STRING_ALLOCATING_STRING_UTILS_H
+
+#include "src/__support/CPP/bitset.h"
+#include "src/__support/common.h"
+#include "src/string/memory_utils/bzero_implementations.h"
+#include "src/string/memory_utils/memcpy_implementations.h"
+#include "src/string/string_utils.h"
+#include <stddef.h> // For size_t
+#include <stdlib.h> // For malloc
+
+namespace __llvm_libc {
+namespace internal {
+
+inline char *strdup(const char *src) {
+  if (src == nullptr)
+    return nullptr;
+  size_t len = string_length(src) + 1;
+  char *newstr = reinterpret_cast<char *>(::malloc(len));
+  if (newstr == nullptr)
+    return nullptr;
+  inline_memcpy(newstr, src, len);
+  return newstr;
+}
+
+} // namespace internal
+} // namespace __llvm_libc
+
+#endif
diff --git a/libc/src/string/strdup.cpp b/libc/src/string/strdup.cpp
index d7adc85..9a52b29 100644
--- a/libc/src/string/strdup.cpp
+++ b/libc/src/string/strdup.cpp
@@ -7,8 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/string/strdup.h"
+#include "src/string/allocating_string_utils.h"
 #include "src/string/memory_utils/memcpy_implementations.h"
-#include "src/string/string_utils.h"
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/string/string_utils.h b/libc/src/string/string_utils.h
index da4ad8e..f8de696 100644
--- a/libc/src/string/string_utils.h
+++ b/libc/src/string/string_utils.h
@@ -5,6 +5,11 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+//
+// Standalone string utility functions. Utilities requiring memory allocations
+// should be placed in allocating_string_utils.h intead.
+//
+//===----------------------------------------------------------------------===//
 
 #ifndef LIBC_SRC_STRING_STRING_UTILS_H
 #define LIBC_SRC_STRING_STRING_UTILS_H
@@ -14,7 +19,6 @@
 #include "src/string/memory_utils/bzero_implementations.h"
 #include "src/string/memory_utils/memcpy_implementations.h"
 #include <stddef.h> // For size_t
-#include <stdlib.h> // For malloc and free
 
 namespace __llvm_libc {
 namespace internal {
@@ -99,17 +103,6 @@ static inline size_t strlcpy(char *__restrict dst, const char *__restrict src,
   return len;
 }
 
-inline char *strdup(const char *src) {
-  if (src == nullptr)
-    return nullptr;
-  size_t len = string_length(src) + 1;
-  char *newstr = reinterpret_cast<char *>(::malloc(len));
-  if (newstr == nullptr)
-    return nullptr;
-  inline_memcpy(newstr, src, len);
-  return newstr;
-}
-
 } // namespace internal
 } // namespace __llvm_libc
 
diff --git a/libc/src/unistd/linux/getcwd.cpp b/libc/src/unistd/linux/getcwd.cpp
index 7475f46..84a16b3 100644
--- a/libc/src/unistd/linux/getcwd.cpp
+++ b/libc/src/unistd/linux/getcwd.cpp
@@ -10,7 +10,7 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
-#include "src/string/string_utils.h" // For strdup.
+#include "src/string/allocating_string_utils.h" // For strdup.
 
 #include <errno.h>
 #include <linux/limits.h> // This is safe to include without any name pollution.
-- 
2.7.4