[libc] Rearrange error and signal tables.

This is largely a cosmetic change done with a few goals:
1. Reduce the conditionals in picking the correct set of tables for the
   platform.
2. Avoid exposing, for example Linux errors, when building for non-Linux
   platforms. This also prevents build failures when Linux errors are not
   defined on the target non-Linux platform.
3. Some "_table" suffixes have been removed to avoid repeated
   occurance of "table" like "tables/linux_error_table.h".

Reviewed By: michaelrj

Differential Revision: https://reviews.llvm.org/D151367

Author: Siva Chandra Reddy

libc/src/__support/StringUtil/CMakeLists.txt

@@ -3,13 +3,38 @@ add_header_library(
   HDRS
     message_mapper.h
   DEPENDS
+    libc.src.__support.CPP.array
     libc.src.__support.CPP.string_view
     libc.src.__support.CPP.optional
 )
 
 # The table maps depend on message_mapper.
 add_subdirectory(tables)
 
+add_header_library(
+  platform_errors
+  HDRS
+    platform_errors.h
+  DEPENDS
+    # To avoid complicated conditionals, we will unconditionally add dependency
+    # on all platform errors which are included in platform_error_table.h.
+    # Ultimately, only the relevent error table will be used.
+    .tables.linux_platform_errors
+    .tables.minimal_platform_errors
+)
+
+add_header_library(
+  platform_signals
+  HDRS
+    platform_signals.h
+  DEPENDS
+    # To avoid complicated conditionals, we will unconditionally add dependency
+    # on all platform signals which are included in platform_signal_table.h.
+    # Ultimately, only the relevent signal table will be used.
+    .tables.linux_platform_signals
+    .tables.minimal_platform_signals
+)
+
 add_object_library(
   error_to_string
   HDRS
@@ -18,12 +43,11 @@ add_object_library(
     error_to_string.cpp
   DEPENDS
     .message_mapper
-    libc.src.errno.errno
+    .platform_errors
     libc.src.__support.CPP.span
     libc.src.__support.CPP.string_view
     libc.src.__support.CPP.stringstream
     libc.src.__support.integer_to_string
-    libc.src.__support.StringUtil.tables.error_table
 )
 
 add_object_library(
@@ -34,10 +58,10 @@ add_object_library(
     signal_to_string.cpp
   DEPENDS
     .message_mapper
+    .platform_signals
     libc.include.signal
     libc.src.__support.CPP.span
     libc.src.__support.CPP.string_view
     libc.src.__support.CPP.stringstream
     libc.src.__support.integer_to_string
-    libc.src.__support.StringUtil.tables.signal_table
 )

libc/src/__support/StringUtil/error_to_string.cpp

@@ -6,19 +6,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/__support/StringUtil/error_to_string.h"
+#include "error_to_string.h"
+#include "platform_errors.h"
 
-#include "src/errno/libc_errno.h" // For error macros
-
-#include "src/__support/CPP/array.h"
 #include "src/__support/CPP/span.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/CPP/stringstream.h"
 #include "src/__support/StringUtil/message_mapper.h"
 #include "src/__support/integer_to_string.h"
 
-#include "src/__support/StringUtil/tables/error_table.h"
-
 #include <stddef.h>
 
 namespace __llvm_libc {

libc/src/__support/StringUtil/message_mapper.h

@@ -15,7 +15,6 @@
 #include <stddef.h>
 
 namespace __llvm_libc {
-namespace internal {
 
 struct MsgMapping {
   int num;
@@ -99,7 +98,6 @@ constexpr MsgTable<N1 + N2> operator+(const MsgTable<N1> &t1,
   return res;
 }
 
-} // namespace internal
 } // namespace __llvm_libc
 
 #endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_MESSAGE_MAPPER_H

libc/src/__support/StringUtil/platform_errors.h

@@ -0,0 +1,18 @@
+//===-- The error table for the current platform ----------------*- 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_SUPPORT_STRING_UTIL_PLATFORM_ERROR_TABLE_H
+#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_PLATFORM_ERROR_TABLE_H
+
+#if defined(__linux__) || defined(__Fuchsia__)
+#include "tables/linux_platform_errors.h"
+#else
+#include "tables/minimal_platform_errors.h"
+#endif
+
+#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_PLATFORM_ERROR_TABLE_H

libc/src/__support/StringUtil/platform_signals.h

@@ -0,0 +1,18 @@
+//===-- The signal table for the current platform ---------------*- 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_SUPPORT_STRING_UTIL_PLATFORM_SIGNAL_TABLE_H
+#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_PLATFORM_SIGNAL_TABLE_H
+
+#if defined(__linux__) || defined(__Fuchsia__)
+#include "tables/linux_platform_signals.h"
+#else
+#include "tables/minimal_platform_signals.h"
+#endif
+
+#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_PLATFORM_SIGNAL_TABLE_H

libc/src/__support/StringUtil/signal_to_string.cpp

@@ -6,13 +6,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/__support/StringUtil/signal_to_string.h"
+#include "signal_to_string.h"
+#include "platform_signals.h"
 
 #include "src/__support/CPP/span.h"
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/CPP/stringstream.h"
 #include "src/__support/StringUtil/message_mapper.h"
-#include "src/__support/StringUtil/tables/signal_table.h"
 #include "src/__support/integer_to_string.h"
 
 #include <signal.h>

libc/src/__support/StringUtil/tables/CMakeLists.txt

@@ -1,35 +1,89 @@
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
-  add_subdirectory(${LIBC_TARGET_OS})
-endif()
+add_header_library(
+  stdc_errors
+  HDRS
+    stdc_errors.h
+  DEPENDS
+    libc.include.errno
+    libc.src.__support.StringUtil.message_mapper
+)
 
-set(error_to_string_platform_dep "")
-if(TARGET libc.src.__support.StringUtil.tables.${LIBC_TARGET_OS}.error_table)
-  set(error_to_string_platform_dep 
-  libc.src.__support.StringUtil.tables.${LIBC_TARGET_OS}.error_table)
-endif()
+add_header_library(
+  posix_errors
+  HDRS
+    posix_errors.h
+  DEPENDS
+    libc.include.errno
+    libc.src.__support.StringUtil.message_mapper
+)
 
 add_header_library(
-  error_table
+  linux_extension_errors
   HDRS
-    error_table.h  
-    stdc_error_table.h  
-    posix_error_table.h  
+    linux_extension_errors.h
   DEPENDS
-    ${error_to_string_platform_dep}
+    libc.include.errno
+    libc.src.__support.StringUtil.message_mapper
 )
 
-set(signal_to_string_platform_dep "")
-if(TARGET libc.src.__support.StringUtil.tables.${LIBC_TARGET_OS}.signal_table)
-  set(signal_to_string_platform_dep 
-  libc.src.__support.StringUtil.tables.${LIBC_TARGET_OS}.signal_table)
-endif()
+add_header_library(
+  linux_platform_errors
+  HDRS
+    linux_platform_errors
+  DEPENDS
+    .linux_extension_errors
+    .posix_errors
+    .stdc_errors
+)
+
+add_header_library(
+  minimal_platform_errors
+  HDRS
+    minimal_platform_errors
+  DEPENDS
+    .stdc_errors
+)
+
+add_header_library(
+  stdc_signals
+  HDRS
+    stdc_signals.h
+  DEPENDS
+    libc.include.signal
+    libc.src.__support.StringUtil.message_mapper
+)
+
+add_header_library(
+  posix_signals
+  HDRS
+    posix_signals.h
+  DEPENDS
+    libc.include.signal
+    libc.src.__support.StringUtil.message_mapper
+)
+
+add_header_library(
+  linux_extension_signals
+  HDRS
+    linux_extension_signals.h
+  DEPENDS
+    libc.include.signal
+    libc.src.__support.StringUtil.message_mapper
+)
+
+add_header_library(
+  linux_platform_signals
+  HDRS
+    linux_platform_signals
+  DEPENDS
+    .linux_extension_signals
+    .posix_signals
+    .stdc_signals
+)
 
 add_header_library(
-  signal_table
+  minimal_platform_signals
   HDRS
-    signal_table.h  
-    stdc_signal_table.h  
-    posix_signal_table.h  
+    minimal_platform_signals
   DEPENDS
-    ${signal_to_string_platform_dep}
+    .stdc_signals
 )

libc/src/__support/StringUtil/tables/error_table.h

@@ -1,20 +1,19 @@
-//===-- Map from error numbers to strings on linux --------------*- C++ -*-===//
+//===-- Map of Linux extension error numbers to strings ---------*- 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_SUPPORT_STRING_UTIL_TABLES_LINUX_ERROR_TABLE_H
-#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_ERROR_TABLE_H
+#ifndef LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_ERRORS_H
+#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_ERRORS_H
 
-#include "src/errno/libc_errno.h" // For error macros
-
-#include "src/__support/CPP/array.h"
 #include "src/__support/StringUtil/message_mapper.h"
 
-namespace __llvm_libc::internal {
+#include <errno.h> // For error macros
+
+namespace __llvm_libc {
 
 constexpr MsgTable<52> LINUX_ERRORS = {
     MsgMapping(ENOTBLK, "Block device required"),
@@ -71,6 +70,6 @@ constexpr MsgTable<52> LINUX_ERRORS = {
     MsgMapping(EHWPOISON, "Memory page has hardware error"),
 };
 
-} // namespace __llvm_libc::internal
+} // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_ERROR_TABLE_H
+#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_ERRORS_H

libc/src/__support/StringUtil/tables/linux/CMakeLists.txt

@@ -1,19 +1,19 @@
-//===-- Map from signal numbers to strings on linux -------------*- C++ -*-===//
+//===-- Map of Linux extension signal numbers to strings --------*- 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_SUPPORT_STRING_UTIL_TABLES_LINUX_SIGNAL_TABLE_H
-#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_SIGNAL_TABLE_H
-
-#include <signal.h>
+#ifndef LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_SIGNALS_H
+#define LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_SIGNALS_H
 
 #include "src/__support/StringUtil/message_mapper.h"
 
-namespace __llvm_libc::internal {
+#include <signal.h> // For signal numbers
+
+namespace __llvm_libc {
 
 // The array being larger than necessary isn't a problem. The MsgMappings will
 // be set to their default state which maps 0 to an empty string. This will get
@@ -28,6 +28,6 @@ inline constexpr const MsgTable<3> LINUX_SIGNALS = {
 #endif
 };
 
-} // namespace __llvm_libc::internal
+} // namespace __llvm_libc
 
-#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_SIGNAL_TABLE_H
+#endif // LLVM_LIBC_SRC_SUPPORT_STRING_UTIL_TABLES_LINUX_EXTENSION_SIGNALS_H