[llvm] [CMake] Declare all parts of *GenRegisterInfo.inc as outputs. (PR #168405)

[Ivan Kosarev via llvm-commits]

https://github.com/kosarev updated https://github.com/llvm/llvm-project/pull/168405

>From 3c3dbaa6fdd55246da46cdf1502dede1a1d2df46 Mon Sep 17 00:00:00 2001
From: Ivan Kosarev <ivan.kosarev at amd.com>
Date: Mon, 17 Nov 2025 15:55:56 +0000
Subject: [PATCH] [CMake] Declare all parts of *GenRegisterInfo.inc as outputs.

This tells the build system to check and regenerate the
*GenRegisterInfo*.inc files, should any of them be missing for
whatever reason.

A follow-up from
<https://github.com/llvm/llvm-project/pull/167700>.
---
 llvm/cmake/modules/TableGen.cmake           | 12 +++++++++++-
 llvm/utils/TableGen/RegisterInfoEmitter.cpp |  2 ++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/llvm/cmake/modules/TableGen.cmake b/llvm/cmake/modules/TableGen.cmake
index 9a2e73a1e3718..84c03cd6432ed 100644
--- a/llvm/cmake/modules/TableGen.cmake
+++ b/llvm/cmake/modules/TableGen.cmake
@@ -66,6 +66,16 @@ function(tablegen project ofn)
     list(APPEND LLVM_TABLEGEN_FLAGS "-omit-comments")
   endif()
 
+  set(EXTRA_OUTPUTS)
+  if("-gen-register-info" IN_LIST ARGN)
+    cmake_path(GET ofn STEM OUTPUT_BASENAME)
+    list(APPEND EXTRA_OUTPUTS
+         ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_BASENAME}Enums.inc
+         ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_BASENAME}Header.inc
+         ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_BASENAME}MCDesc.inc
+         ${CMAKE_CURRENT_BINARY_DIR}/${OUTPUT_BASENAME}TargetDesc.inc)
+  endif()
+
   # MSVC can't support long string literals ("long" > 65534 bytes)[1], so if there's
   # a possibility of generated tables being consumed by MSVC, generate arrays of
   # char literals, instead. If we're cross-compiling, then conservatively assume
@@ -126,7 +136,7 @@ function(tablegen project ofn)
     set(LLVM_TABLEGEN_JOB_POOL "")
   endif()
 
-  add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
+  add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn} ${EXTRA_OUTPUTS}
     COMMAND ${tablegen_exe} ${ARG_UNPARSED_ARGUMENTS}
     ${tblgen_includes}
     ${LLVM_TABLEGEN_FLAGS}
diff --git a/llvm/utils/TableGen/RegisterInfoEmitter.cpp b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
index ef7b13e8940f8..3486a7a7fb08c 100644
--- a/llvm/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
@@ -1878,6 +1878,8 @@ TableGenOutputFiles RegisterInfoEmitter::run(StringRef FilenamePrefix) {
   if (RegisterInfoDebug)
     debugDump(errs());
 
+  // The suffixes should be in sync with the tablegen function in
+  // llvm/cmake/modules/TableGen.cmake.
   return {Main,
           {{"Enums.inc", Enums},
            {"MCDesc.inc", MCDesc},