[libc-commits] [libc] afae7c9 - [libc] Support for scanf on baremetal (#131043)
via libc-commits
libc-commits at lists.llvm.org
Thu Mar 20 15:54:41 PDT 2025
Author: Petr Hosek
Date: 2025-03-20T15:54:38-07:00
New Revision: afae7c91e19f0e9d6f1e03ebada64d740894abc7
URL: https://github.com/llvm/llvm-project/commit/afae7c91e19f0e9d6f1e03ebada64d740894abc7
DIFF: https://github.com/llvm/llvm-project/commit/afae7c91e19f0e9d6f1e03ebada64d740894abc7.diff
LOG: [libc] Support for scanf on baremetal (#131043)
This uses the templatized scanf Reader interface introduced in #131037.
Added:
libc/src/stdio/baremetal/scanf.cpp
libc/src/stdio/baremetal/scanf_internal.h
libc/src/stdio/baremetal/vscanf.cpp
libc/src/stdio/generic/fscanf.cpp
libc/src/stdio/generic/scanf.cpp
libc/src/stdio/generic/vfscanf.cpp
libc/src/stdio/generic/vscanf.cpp
Modified:
libc/config/baremetal/aarch64/entrypoints.txt
libc/config/baremetal/arm/entrypoints.txt
libc/config/baremetal/riscv/entrypoints.txt
libc/src/stdio/CMakeLists.txt
libc/src/stdio/baremetal/CMakeLists.txt
libc/src/stdio/baremetal/getchar.cpp
libc/src/stdio/generic/CMakeLists.txt
libc/src/stdio/scanf_core/CMakeLists.txt
Removed:
libc/src/stdio/fscanf.cpp
libc/src/stdio/scanf.cpp
libc/src/stdio/vfscanf.cpp
libc/src/stdio/vscanf.cpp
################################################################################
diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
index 2c226ef176c08..8b51942d30fe8 100644
--- a/libc/config/baremetal/aarch64/entrypoints.txt
+++ b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -123,18 +123,22 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.inttypes.strtoumax
# stdio.h entrypoints
+ libc.src.stdio.asprintf
libc.src.stdio.getchar
libc.src.stdio.printf
libc.src.stdio.putchar
libc.src.stdio.puts
libc.src.stdio.remove
+ libc.src.stdio.scanf
libc.src.stdio.snprintf
libc.src.stdio.sprintf
- libc.src.stdio.asprintf
+ libc.src.stdio.sscanf
+ libc.src.stdio.vasprintf
libc.src.stdio.vprintf
+ libc.src.stdio.vscanf
libc.src.stdio.vsnprintf
libc.src.stdio.vsprintf
- libc.src.stdio.vasprintf
+ libc.src.stdio.vsscanf
# stdbit.h entrypoints
libc.src.stdbit.stdc_bit_ceil_uc
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
index d7a01bdf90b3f..511d9d22f1450 100644
--- a/libc/config/baremetal/arm/entrypoints.txt
+++ b/libc/config/baremetal/arm/entrypoints.txt
@@ -123,18 +123,22 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.inttypes.strtoumax
# stdio.h entrypoints
+ libc.src.stdio.asprintf
libc.src.stdio.getchar
libc.src.stdio.printf
libc.src.stdio.putchar
libc.src.stdio.puts
libc.src.stdio.remove
+ libc.src.stdio.scanf
libc.src.stdio.snprintf
libc.src.stdio.sprintf
- libc.src.stdio.asprintf
+ libc.src.stdio.sscanf
+ libc.src.stdio.vasprintf
libc.src.stdio.vprintf
+ libc.src.stdio.vscanf
libc.src.stdio.vsnprintf
libc.src.stdio.vsprintf
- libc.src.stdio.vasprintf
+ libc.src.stdio.vsscanf
# 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
index ae00803dd0def..bbefb75ee16b5 100644
--- a/libc/config/baremetal/riscv/entrypoints.txt
+++ b/libc/config/baremetal/riscv/entrypoints.txt
@@ -119,18 +119,22 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.inttypes.strtoumax
# stdio.h entrypoints
+ libc.src.stdio.asprintf
libc.src.stdio.getchar
libc.src.stdio.printf
libc.src.stdio.putchar
libc.src.stdio.puts
libc.src.stdio.remove
+ libc.src.stdio.scanf
libc.src.stdio.snprintf
libc.src.stdio.sprintf
- libc.src.stdio.asprintf
+ libc.src.stdio.sscanf
+ libc.src.stdio.vasprintf
libc.src.stdio.vprintf
+ libc.src.stdio.vscanf
libc.src.stdio.vsnprintf
libc.src.stdio.vsprintf
- libc.src.stdio.vasprintf
+ libc.src.stdio.vsscanf
# stdbit.h entrypoints
libc.src.stdbit.stdc_bit_ceil_uc
diff --git a/libc/src/stdio/CMakeLists.txt b/libc/src/stdio/CMakeLists.txt
index ce5d0660ff81f..b4df8fa497d46 100644
--- a/libc/src/stdio/CMakeLists.txt
+++ b/libc/src/stdio/CMakeLists.txt
@@ -95,20 +95,6 @@ add_entrypoint_object(
libc.src.__support.File.platform_file
)
-list(APPEND scanf_deps
- libc.src.__support.arg_list
- libc.src.stdio.scanf_core.vfscanf_internal
- libc.hdr.types.FILE
-)
-
-if(LLVM_LIBC_FULL_BUILD AND NOT LIBC_TARGET_OS_IS_GPU)
- list(APPEND scanf_deps
- libc.src.__support.File.file
- libc.src.__support.File.platform_file
- libc.src.__support.File.platform_stdin
- )
-endif()
-
add_entrypoint_object(
sscanf
SRCS
@@ -133,46 +119,6 @@ add_entrypoint_object(
libc.src.stdio.scanf_core.string_reader
)
-add_entrypoint_object(
- fscanf
- SRCS
- fscanf.cpp
- HDRS
- fscanf.h
- DEPENDS
- ${scanf_deps}
-)
-
-add_entrypoint_object(
- vfscanf
- SRCS
- vfscanf.cpp
- HDRS
- vfscanf.h
- DEPENDS
- ${scanf_deps}
-)
-
-add_entrypoint_object(
- scanf
- SRCS
- scanf.cpp
- HDRS
- scanf.h
- DEPENDS
- ${scanf_deps}
-)
-
-add_entrypoint_object(
- vscanf
- SRCS
- vscanf.cpp
- HDRS
- vscanf.h
- DEPENDS
- ${scanf_deps}
-)
-
add_entrypoint_object(
sprintf
SRCS
@@ -295,8 +241,12 @@ add_stdio_entrypoint_object(getchar)
add_stdio_entrypoint_object(getchar_unlocked)
add_stdio_entrypoint_object(fgets)
add_stdio_entrypoint_object(ungetc)
+add_stdio_entrypoint_object(scanf)
+add_stdio_entrypoint_object(fscanf)
add_stdio_entrypoint_object(stdin)
add_stdio_entrypoint_object(stdout)
add_stdio_entrypoint_object(stderr)
add_stdio_entrypoint_object(vprintf)
add_stdio_entrypoint_object(vfprintf)
+add_stdio_entrypoint_object(vscanf)
+add_stdio_entrypoint_object(vfscanf)
diff --git a/libc/src/stdio/baremetal/CMakeLists.txt b/libc/src/stdio/baremetal/CMakeLists.txt
index c5cf4a8e0e5b5..e879230a9d02c 100644
--- a/libc/src/stdio/baremetal/CMakeLists.txt
+++ b/libc/src/stdio/baremetal/CMakeLists.txt
@@ -55,6 +55,28 @@ add_entrypoint_object(
libc.src.__support.CPP.string_view
)
+add_header_library(
+ scanf_internal
+ HDRS
+ scanf_internal.h
+ DEPENDS
+ libc.src.stdio.scanf_core.reader
+ libc.src.__support.OSUtil.osutil
+)
+
+add_entrypoint_object(
+ scanf
+ SRCS
+ scanf.cpp
+ HDRS
+ ../scanf.h
+ DEPENDS
+ .scanf_internal
+ libc.src.stdio.scanf_core.scanf_main
+ libc.src.__support.arg_list
+ libc.src.__support.OSUtil.osutil
+)
+
add_entrypoint_object(
vprintf
SRCS
@@ -67,3 +89,16 @@ add_entrypoint_object(
libc.src.__support.arg_list
libc.src.__support.OSUtil.osutil
)
+
+add_entrypoint_object(
+ vscanf
+ SRCS
+ vscanf.cpp
+ HDRS
+ ../vscanf.h
+ DEPENDS
+ .scanf_internal
+ libc.src.stdio.scanf_core.scanf_main
+ libc.src.__support.arg_list
+ libc.src.__support.OSUtil.osutil
+)
diff --git a/libc/src/stdio/baremetal/getchar.cpp b/libc/src/stdio/baremetal/getchar.cpp
index 0a78a1ff8adf1..8fb7bc32537e7 100644
--- a/libc/src/stdio/baremetal/getchar.cpp
+++ b/libc/src/stdio/baremetal/getchar.cpp
@@ -17,7 +17,7 @@ namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(int, getchar, ()) {
char buf[1];
auto result = read_from_stdin(buf, sizeof(buf));
- if (result < 0)
+ if (result <= 0)
return EOF;
return buf[0];
}
diff --git a/libc/src/stdio/baremetal/scanf.cpp b/libc/src/stdio/baremetal/scanf.cpp
new file mode 100644
index 0000000000000..8d07aa1da76aa
--- /dev/null
+++ b/libc/src/stdio/baremetal/scanf.cpp
@@ -0,0 +1,37 @@
+//===-- Implementation of scanf ---------------------------------*- 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/scanf.h"
+
+#include "hdr/stdio_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/arg_list.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/baremetal/scanf_internal.h"
+#include "src/stdio/scanf_core/scanf_main.h"
+
+#include <stdarg.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, scanf, (const char *__restrict 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);
+
+ scanf_core::StdinReader reader;
+ int retval = scanf_core::scanf_main(&reader, format, args);
+ // This is done to avoid including stdio.h in the internals. On most systems
+ // EOF is -1, so this will be transformed into just "return retval".
+ return (retval == -1) ? EOF : retval;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/scanf_internal.h b/libc/src/stdio/baremetal/scanf_internal.h
new file mode 100644
index 0000000000000..57d4b8c8d1a61
--- /dev/null
+++ b/libc/src/stdio/baremetal/scanf_internal.h
@@ -0,0 +1,30 @@
+//===-- Internal implementation header of scanf -----------------*- 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/OSUtil/io.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/scanf_core/reader.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace scanf_core {
+
+struct StdinReader : public Reader<StdinReader> {
+ LIBC_INLINE char getc() {
+ char buf[1];
+ auto result = read_from_stdin(buf, sizeof(buf));
+ if (result <= 0)
+ return EOF;
+ return buf[0];
+ }
+ LIBC_INLINE void ungetc(int) {}
+};
+
+} // namespace scanf_core
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/vscanf.cpp b/libc/src/stdio/baremetal/vscanf.cpp
new file mode 100644
index 0000000000000..249f8fd5dbe3c
--- /dev/null
+++ b/libc/src/stdio/baremetal/vscanf.cpp
@@ -0,0 +1,36 @@
+//===-- Implementation of vscanf --------------------------------*- 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/vscanf.h"
+
+#include "hdr/stdio_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/arg_list.h"
+#include "src/__support/macros/config.h"
+#include "src/stdio/baremetal/scanf_internal.h"
+#include "src/stdio/scanf_core/scanf_main.h"
+
+#include <stdarg.h>
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, vscanf,
+ (const char *__restrict format, va_list vlist)) {
+ internal::ArgList args(vlist); // This holder class allows for easier copying
+ // and pointer semantics, as well as handling
+ // destruction automatically.
+ va_end(vlist);
+
+ scanf_core::StdinReader reader;
+ int retval = scanf_core::scanf_main(&reader, format, args);
+ // This is done to avoid including stdio.h in the internals. On most systems
+ // EOF is -1, so this will be transformed into just "return retval".
+ return (retval == -1) ? EOF : retval;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/generic/CMakeLists.txt b/libc/src/stdio/generic/CMakeLists.txt
index bf301a6b0cb3c..9f568c5ab8d3a 100644
--- a/libc/src/stdio/generic/CMakeLists.txt
+++ b/libc/src/stdio/generic/CMakeLists.txt
@@ -425,6 +425,60 @@ add_entrypoint_object(
${fprintf_deps}
)
+list(APPEND scanf_deps
+ libc.src.__support.arg_list
+ libc.src.stdio.scanf_core.vfscanf_internal
+ libc.hdr.types.FILE
+)
+
+if(LLVM_LIBC_FULL_BUILD AND NOT LIBC_TARGET_OS_IS_GPU)
+ list(APPEND scanf_deps
+ libc.src.__support.File.file
+ libc.src.__support.File.platform_file
+ libc.src.__support.File.platform_stdin
+ )
+endif()
+
+add_entrypoint_object(
+ fscanf
+ SRCS
+ fscanf.cpp
+ HDRS
+ ../fscanf.h
+ DEPENDS
+ ${scanf_deps}
+)
+
+add_entrypoint_object(
+ vfscanf
+ SRCS
+ vfscanf.cpp
+ HDRS
+ ../vfscanf.h
+ DEPENDS
+ ${scanf_deps}
+)
+
+add_entrypoint_object(
+ scanf
+ SRCS
+ scanf.cpp
+ HDRS
+ ../scanf.h
+ DEPENDS
+ ${scanf_deps}
+)
+
+add_entrypoint_object(
+ vscanf
+ SRCS
+ vscanf.cpp
+ HDRS
+ ../vscanf.h
+ DEPENDS
+ ${scanf_deps}
+)
+
add_entrypoint_object(
fgets
SRCS
diff --git a/libc/src/stdio/fscanf.cpp b/libc/src/stdio/generic/fscanf.cpp
similarity index 100%
rename from libc/src/stdio/fscanf.cpp
rename to libc/src/stdio/generic/fscanf.cpp
diff --git a/libc/src/stdio/scanf.cpp b/libc/src/stdio/generic/scanf.cpp
similarity index 100%
rename from libc/src/stdio/scanf.cpp
rename to libc/src/stdio/generic/scanf.cpp
diff --git a/libc/src/stdio/vfscanf.cpp b/libc/src/stdio/generic/vfscanf.cpp
similarity index 100%
rename from libc/src/stdio/vfscanf.cpp
rename to libc/src/stdio/generic/vfscanf.cpp
diff --git a/libc/src/stdio/vscanf.cpp b/libc/src/stdio/generic/vscanf.cpp
similarity index 100%
rename from libc/src/stdio/vscanf.cpp
rename to libc/src/stdio/generic/vscanf.cpp
diff --git a/libc/src/stdio/scanf_core/CMakeLists.txt b/libc/src/stdio/scanf_core/CMakeLists.txt
index d0d922ac823fe..dee125c234a10 100644
--- a/libc/src/stdio/scanf_core/CMakeLists.txt
+++ b/libc/src/stdio/scanf_core/CMakeLists.txt
@@ -54,13 +54,6 @@ add_header_library(
libc.src.__support.CPP.string_view
)
-if(NOT(TARGET libc.src.__support.File.file) AND LLVM_LIBC_FULL_BUILD AND
- (NOT LIBC_TARGET_OS_IS_GPU))
- # Not all platforms have a file implementation. If file is unvailable, and a
- # full build is requested, then we must skip all file based scanf sections.
- return()
-endif()
-
add_header_library(
scanf_main
HDRS
@@ -71,7 +64,6 @@ add_header_library(
.converter
.core_structs
libc.src.__support.arg_list
- ${file_deps}
${use_system_file}
)
@@ -112,7 +104,6 @@ add_header_library(
libc.src.__support.CPP.limits
libc.src.__support.char_vector
libc.src.__support.str_to_float
- ${file_deps}
${use_system_file}
)
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