[libc-commits] [libc] [libc] Add `vasprintf` function (PR #97528)

[Izaak Schroeder via libc-commits]

https://github.com/izaakschroeder updated https://github.com/llvm/llvm-project/pull/97528

>From 0d4ddc01f0f55dc98e851253efd652126ab18c47 Mon Sep 17 00:00:00 2001
From: Izaak Schroeder <izaak.schroeder at gmail.com>
Date: Tue, 2 Jul 2024 23:53:14 -0700
Subject: [PATCH] [libc] Add `vasprintf` function

---
 libc/spec/stdc.td             |  7 +++++++
 libc/src/stdio/CMakeLists.txt | 10 ++++++++++
 libc/src/stdio/vasprintf.cpp  | 26 ++++++++++++++++++++++++++
 libc/src/stdio/vasprintf.h    | 21 +++++++++++++++++++++
 4 files changed, 64 insertions(+)
 create mode 100644 libc/src/stdio/vasprintf.cpp
 create mode 100644 libc/src/stdio/vasprintf.h

diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 9ff40bf76700c..6902bbfe14417 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -968,6 +968,13 @@ def StdC : StandardSpec<"stdc"> {
               RetValSpec<IntType>,
               [ArgSpec<IntType>, ArgSpec<FILEPtr>]
           >,
+          FunctionSpec<
+              "vasprintf",
+              RetValSpec<IntType>,
+              [ArgSpec<CharRestrictedPtrPtr>,
+               ArgSpec<ConstCharPtr>,
+               ArgSpec<VaListType>]
+          >,
       ],
       [
           ObjectSpec<
diff --git a/libc/src/stdio/CMakeLists.txt b/libc/src/stdio/CMakeLists.txt
index a659d9e847a9e..300a97ca4377a 100644
--- a/libc/src/stdio/CMakeLists.txt
+++ b/libc/src/stdio/CMakeLists.txt
@@ -203,6 +203,16 @@ add_entrypoint_object(
     libc.src.stdio.printf_core.vfprintf_internal
 )
 
+add_entrypoint_object(
+  vasprintf
+  SRCS
+    vasprintf.cpp
+  HDRS
+    vasprintf.h
+  DEPENDS
+    libc.src.__support.arg_list
+)
+
 add_stdio_entrypoint_object(
   fileno
   SRCS
diff --git a/libc/src/stdio/vasprintf.cpp b/libc/src/stdio/vasprintf.cpp
new file mode 100644
index 0000000000000..712a3f72ab62d
--- /dev/null
+++ b/libc/src/stdio/vasprintf.cpp
@@ -0,0 +1,26 @@
+//===-- Implementation of vasprintf -----------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/vasprintf.h"
+
+#include "src/__support/arg_list.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, vasprintf,
+                   (char **__restrict, const char *, va_list vlist)) {
+  internal::ArgList args(vlist); // This holder class allows for easier copying
+                                 // and pointer semantics, as well as handling
+                                 // destruction automatically.
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdio/vasprintf.h b/libc/src/stdio/vasprintf.h
new file mode 100644
index 0000000000000..c11675461e3fb
--- /dev/null
+++ b/libc/src/stdio/vasprintf.h
@@ -0,0 +1,21 @@
+//===-- Implementation header of vasprintf ----------------------*- 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 LLVM_LIBC_SRC_STDIO_VASPRINTF_H
+#define LLVM_LIBC_SRC_STDIO_VASPRINTF_H
+
+#include <stdarg.h>
+#include <stdio.h>
+
+namespace LIBC_NAMESPACE {
+
+int vasprintf(char **__restrict s, const char *format, va_list vlist);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDIO_VASPRINTF_H