[libc] Implement vasprintf and asprintf (llvm#98824)

tszhin-swe · izaakschroeder · web-flow · commit a5e67fba8abb · 2024-08-01T11:52:36.000-05:00
[libc] Implement vasprintf and asprintf

---------

Co-authored-by: Izaak Schroeder &lt;izaak.schroeder@gmail.com&gt;
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
@@ -90,9 +90,11 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.remove
     libc.src.stdio.snprintf
     libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
     libc.src.stdio.vprintf
     libc.src.stdio.vsnprintf
     libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 
     # stdbit.h entrypoints
     libc.src.stdbit.stdc_bit_ceil_uc
diff --git a/libc/config/baremetal/riscv/entrypoints.txt b/libc/config/baremetal/riscv/entrypoints.txt
@@ -86,9 +86,11 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.remove
     libc.src.stdio.snprintf
     libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
     libc.src.stdio.vprintf
     libc.src.stdio.vsnprintf
     libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 
     # stdbit.h entrypoints
     libc.src.stdbit.stdc_bit_ceil_uc
diff --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
@@ -94,6 +94,16 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.calloc
     libc.src.stdlib.realloc
     libc.src.stdlib.free
+
+    # stdio.h external entrypoints
+    libc.src.stdio.snprintf
+    libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
+    libc.src.stdio.asprintf
+    libc.src.stdio.vprintf
+    libc.src.stdio.vsnprintf
+    libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 )
 
 set(TARGET_LIBM_ENTRYPOINTS
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -207,10 +207,12 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.rename
     libc.src.stdio.snprintf
     libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
     #libc.src.stdio.scanf
     #libc.src.stdio.sscanf
     libc.src.stdio.vsnprintf
     libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 
     # sys/mman.h entrypoints
     libc.src.sys.mman.madvise
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
@@ -216,12 +216,14 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.scanf
     libc.src.stdio.snprintf
     libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
     libc.src.stdio.sscanf
     libc.src.stdio.vsscanf
     libc.src.stdio.vfprintf
     libc.src.stdio.vprintf
     libc.src.stdio.vsnprintf
     libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 
     # sys/epoll.h entrypoints
     libc.src.sys.epoll.epoll_create
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -216,12 +216,14 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.scanf
     libc.src.stdio.snprintf
     libc.src.stdio.sprintf
+    libc.src.stdio.asprintf
     libc.src.stdio.sscanf
     libc.src.stdio.vsscanf
     libc.src.stdio.vfprintf
     libc.src.stdio.vprintf
     libc.src.stdio.vsnprintf
     libc.src.stdio.vsprintf
+    libc.src.stdio.vasprintf
 
     # sys/epoll.h entrypoints
     libc.src.sys.epoll.epoll_create
diff --git a/libc/newhdrgen/yaml/stdio.yaml b/libc/newhdrgen/yaml/stdio.yaml
@@ -97,6 +97,22 @@ functions:
     arguments:
       - type: const char *__restrict
       - type: va_list
+  - name: asprintf  
+    standards: 
+      - GNUExtensions  
+    return_type: int  
+    arguments:  
+      - type: char **__restrict  
+      - type: const char *__restrict  
+      - type: ...  
+  - name: vasprintf  
+    standards: 
+      - GNUExtensions  
+    return_type: int  
+    arguments:  
+      - type: char **__restrict  
+      - type: const char *__restrict  
+      - type: va_list 
   - name: sscanf
     standards: 
       - stdc
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
@@ -971,6 +971,13 @@ def StdC : StandardSpec<"stdc"> {
                ArgSpec<ConstCharRestrictedPtr>,
                ArgSpec<VarArgType>]
           >,
+          FunctionSpec<
+              "asprintf",
+              RetValSpec<IntType>,
+              [ArgSpec<CharRestrictedPtrPtr>,
+               ArgSpec<ConstCharRestrictedPtr>,
+               ArgSpec<VarArgType>]
+          >,
           FunctionSpec<
               "vsprintf",
               RetValSpec<IntType>,
@@ -1004,6 +1011,13 @@ def StdC : StandardSpec<"stdc"> {
               RetValSpec<IntType>,
               [ArgSpec<IntType>, ArgSpec<FILEPtr>]
           >,
+          FunctionSpec<
+              "vasprintf",
+              RetValSpec<IntType>,
+              [ArgSpec<CharRestrictedPtrPtr>,
+               ArgSpec<ConstCharRestrictedPtr>,
+               ArgSpec<VaListType>]
+          >,
       ],
       [
           ObjectSpec<
diff --git a/libc/src/stdio/CMakeLists.txt b/libc/src/stdio/CMakeLists.txt
@@ -175,6 +175,16 @@ add_entrypoint_object(
     libc.src.stdio.printf_core.writer
 )
 
+add_entrypoint_object(
+  asprintf
+  SRCS
+    asprintf.cpp
+  HDRS
+    asprintf.h
+  DEPENDS
+    libc.src.stdio.printf_core.vasprintf_internal
+)
+
 add_entrypoint_object(
   vsprintf
   SRCS
@@ -197,6 +207,16 @@ add_entrypoint_object(
     libc.src.stdio.printf_core.writer
 )
 
+add_entrypoint_object(
+  vasprintf
+  SRCS
+    vasprintf.cpp
+  HDRS
+    vasprintf.h
+  DEPENDS
+    libc.src.stdio.printf_core.vasprintf_internal
+)
+
 add_subdirectory(printf_core)
 add_subdirectory(scanf_core)
 
diff --git a/libc/src/stdio/asprintf.cpp b/libc/src/stdio/asprintf.cpp
@@ -0,0 +1,28 @@
+//===-- Implementation of asprintf -----------------------------*- 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/asprintf.h"
+#include "src/__support/arg_list.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/printf_core/vasprintf_internal.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, asprintf,
+                   (char **__restrict buffer, const char *format, ...)) {
+  va_list vlist;
+  va_start(vlist, format);
+  internal::ArgList args(vlist); // This holder class allows for easier copying
+                                 // and pointer semantics, as well as handling
+                                 // destruction automatically.
+  va_end(vlist);
+  int ret = printf_core::vasprintf_internal(buffer, format, args);
+  return ret;
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdio/asprintf.h b/libc/src/stdio/asprintf.h
@@ -0,0 +1,22 @@
+//===-- Implementation header of asprintf ----------------------*- 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_ASPRINTF_H
+#define LLVM_LIBC_SRC_STDIO_ASPRINTF_H
+
+#include "src/__support/macros/config.h"
+#include <stdarg.h>
+#include <stdio.h>
+
+namespace LIBC_NAMESPACE {
+
+int asprintf(char **__restrict s, const char *format, ...);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDIO_ASPRINTF_H
diff --git a/libc/src/stdio/printf_core/CMakeLists.txt b/libc/src/stdio/printf_core/CMakeLists.txt
@@ -132,3 +132,15 @@ add_header_library(
     libc.src.stdio.printf_core.writer
   ${use_system_file}
 )
+
+add_header_library(
+  vasprintf_internal
+  HDRS
+    vasprintf_internal.h
+  DEPENDS
+    libc.src.__support.arg_list
+    libc.src.stdio.printf_core.printf_main
+    libc.src.stdio.printf_core.writer
+    libc.src.stdlib.malloc
+    libc.src.stdlib.realloc
+)
diff --git a/libc/src/stdio/printf_core/core_structs.h b/libc/src/stdio/printf_core/core_structs.h
@@ -134,7 +134,7 @@ constexpr int FILE_STATUS_ERROR = -2;
 constexpr int NULLPTR_WRITE_ERROR = -3;
 constexpr int INT_CONVERSION_ERROR = -4;
 constexpr int FIXED_POINT_CONVERSION_ERROR = -5;
-
+constexpr int ALLOCATION_ERROR = -6;
 } // namespace printf_core
 } // namespace LIBC_NAMESPACE_DECL
 
diff --git a/libc/src/stdio/printf_core/vasprintf_internal.h b/libc/src/stdio/printf_core/vasprintf_internal.h
@@ -0,0 +1,67 @@
+//===-- Internal Implementation of asprintf ---------------------*- 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/__support/arg_list.h"
+#include "src/stdio/printf.h"
+#include "src/stdio/printf_core/core_structs.h"
+#include "src/stdio/printf_core/printf_main.h"
+#include "src/stdio/printf_core/writer.h"
+#include <stdlib.h> // malloc, realloc, free
+
+namespace LIBC_NAMESPACE {
+namespace printf_core {
+
+LIBC_INLINE int resize_overflow_hook(cpp::string_view new_str, void *target) {
+  printf_core::WriteBuffer *wb =
+      reinterpret_cast<printf_core::WriteBuffer *>(target);
+  size_t new_size = new_str.size() + wb->buff_cur;
+  const bool isBuffOnStack = (wb->buff == wb->init_buff);
+  char *new_buff = static_cast<char *>(
+      isBuffOnStack ? malloc(new_size + 1)
+                    : realloc(wb->buff, new_size + 1)); // +1 for null
+  if (new_buff == nullptr) {
+    if (wb->buff != wb->init_buff)
+      free(wb->buff);
+    return printf_core::ALLOCATION_ERROR;
+  }
+  if (isBuffOnStack)
+    inline_memcpy(new_buff, wb->buff, wb->buff_cur);
+  wb->buff = new_buff;
+  inline_memcpy(wb->buff + wb->buff_cur, new_str.data(), new_str.size());
+  wb->buff_cur = new_size;
+  wb->buff_len = new_size;
+  return printf_core::WRITE_OK;
+}
+
+constexpr size_t DEFAULT_BUFFER_SIZE = 200;
+
+LIBC_INLINE int vasprintf_internal(char **ret, const char *format,
+                                   internal::ArgList args) {
+  char init_buff_on_stack[DEFAULT_BUFFER_SIZE];
+  printf_core::WriteBuffer wb(init_buff_on_stack, DEFAULT_BUFFER_SIZE,
+                              resize_overflow_hook);
+  printf_core::Writer writer(&wb);
+
+  auto ret_val = printf_core::printf_main(&writer, format, args);
+  if (ret_val < 0) {
+    *ret = nullptr;
+    return -1;
+  }
+  if (wb.buff == init_buff_on_stack) {
+    *ret = static_cast<char *>(malloc(ret_val + 1));
+    if (ret == nullptr)
+      return printf_core::ALLOCATION_ERROR;
+    inline_memcpy(*ret, wb.buff, ret_val);
+  } else {
+    *ret = wb.buff;
+  }
+  (*ret)[ret_val] = '\0';
+  return ret_val;
+}
+} // namespace printf_core
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdio/printf_core/writer.h b/libc/src/stdio/printf_core/writer.h
diff --git a/libc/src/stdio/vasprintf.cpp b/libc/src/stdio/vasprintf.cpp
diff --git a/libc/src/stdio/vasprintf.h b/libc/src/stdio/vasprintf.h
diff --git a/libc/test/src/stdio/CMakeLists.txt b/libc/test/src/stdio/CMakeLists.txt
diff --git a/libc/test/src/stdio/asprintf_test.cpp b/libc/test/src/stdio/asprintf_test.cpp
diff --git a/libc/test/src/stdio/vasprintf_test.cpp b/libc/test/src/stdio/vasprintf_test.cpp
