[CMake] Remove HAVE_LINK_H

[MaskRay]

We can remove the variable from https://reviews.llvm.org/D5610 since
link.h is available on Linux (glibc/musl/Bionic), FreeBSD, and NetBSD.
Use __has_include(<link.h>) before including it.

[llvmbot]

@llvm/pr-subscribers-llvm-support

Author: Fangrui Song (MaskRay)

Changes

We can remove the variable from https://reviews.llvm.org/D5610 since
link.h is available on Linux (glibc/musl/Bionic), FreeBSD, and NetBSD.

---

Full diff: https://github.com/llvm/llvm-project/pull/104893.diff

8 Files Affected:

• (modified) llvm/cmake/config-ix.cmake (-1)
• (modified) llvm/include/llvm/Config/config.h.cmake (-3)
• (modified) llvm/lib/Support/Unix/Signals.inc (+1-4)
• (modified) llvm/unittests/Support/SignalsTest.cpp (+1-1)
• (modified) llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn (-2)
• (modified) utils/bazel/llvm-project-overlay/llvm/config.bzl (-1)
• (modified) utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h (-3)
• (modified) utils/bazel/llvm_configs/config.h.cmake (-3)

diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index 0aae13e30f2ab4..f76eacb9d51366 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -44,7 +44,6 @@ endif()
 check_include_file(dlfcn.h HAVE_DLFCN_H)
 check_include_file(errno.h HAVE_ERRNO_H)
 check_include_file(fcntl.h HAVE_FCNTL_H)
-check_include_file(link.h HAVE_LINK_H)
 check_include_file(malloc/malloc.h HAVE_MALLOC_MALLOC_H)
 if( NOT PURE_WINDOWS )
   check_include_file(pthread.h HAVE_PTHREAD_H)
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
index ff30741c8f360a..f39d2d56d61e89 100644
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -125,9 +125,6 @@
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
-/* Define to 1 if you have the <link.h> header file. */
-#cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}
 
diff --git a/llvm/lib/Support/Unix/Signals.inc b/llvm/lib/Support/Unix/Signals.inc
index 298fde1a387cc5..196e2f0e336350 100644
--- a/llvm/lib/Support/Unix/Signals.inc
+++ b/llvm/lib/Support/Unix/Signals.inc
@@ -65,9 +65,6 @@
 #ifdef __APPLE__
 #include <mach-o/dyld.h>
 #endif
-#if HAVE_LINK_H
-#include <link.h>
-#endif
 #ifdef HAVE__UNWIND_BACKTRACE
 // FIXME: We should be able to use <unwind.h> for any target that has an
 // _Unwind_Backtrace function, but on FreeBSD the configure test passes
@@ -464,7 +461,7 @@ void llvm::sys::AddSignalHandler(sys::SignalHandlerCallback FnPtr,
   RegisterHandlers();
 }
 
-#if ENABLE_BACKTRACES && defined(HAVE_BACKTRACE) && HAVE_LINK_H &&             \
+#if ENABLE_BACKTRACES && defined(HAVE_BACKTRACE) &&                            \
     (defined(__linux__) || defined(__FreeBSD__) ||                             \
      defined(__FreeBSD_kernel__) || defined(__NetBSD__))
 struct DlIteratePhdrData {
diff --git a/llvm/unittests/Support/SignalsTest.cpp b/llvm/unittests/Support/SignalsTest.cpp
index a41b37c8f82c94..296478567e2903 100644
--- a/llvm/unittests/Support/SignalsTest.cpp
+++ b/llvm/unittests/Support/SignalsTest.cpp
@@ -29,7 +29,7 @@ using testing::Not;
 // %i in the Symbolizer Markup Format spec
 #define I_REGEX "(0x[0-9a-fA-F]+|0[0-7]+|[0-9]+)"
 
-#if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES && HAVE_LINK_H &&             \
+#if defined(HAVE_BACKTRACE) && ENABLE_BACKTRACES &&                            \
     (defined(__linux__) || defined(__FreeBSD__) ||                             \
      defined(__FreeBSD_kernel__) || defined(__NetBSD__))
 TEST(SignalsTest, PrintsSymbolizerMarkup) {
diff --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
index 1b0d4a10e4610e..1c9c19241508a7 100644
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -140,14 +140,12 @@ write_cmake_config("config") {
   if (current_os == "linux" || current_os == "android") {
     values += [
       "HAVE_FUTIMENS=1",
-      "HAVE_LINK_H=1",
       "HAVE_MALLINFO=1",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
     ]
   } else {
     values += [
       "HAVE_FUTIMENS=",
-      "HAVE_LINK_H=",
       "HAVE_MALLINFO=",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=",
     ]
diff --git a/utils/bazel/llvm-project-overlay/llvm/config.bzl b/utils/bazel/llvm-project-overlay/llvm/config.bzl
index 9de966688eda50..6e703d22e77567 100644
--- a/utils/bazel/llvm-project-overlay/llvm/config.bzl
+++ b/utils/bazel/llvm-project-overlay/llvm/config.bzl
@@ -47,7 +47,6 @@ posix_defines = [
 
 linux_defines = posix_defines + [
     "_GNU_SOURCE",
-    "HAVE_LINK_H=1",
     "HAVE_MALLINFO=1",
     "HAVE_SBRK=1",
     "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
diff --git a/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h b/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
index a4fb47d677ab15..15696c346bff17 100644
--- a/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
+++ b/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
@@ -141,9 +141,6 @@
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #define HAVE_PTHREAD_SETNAME_NP 1
 
-/* Define to 1 if you have the <link.h> header file. */
-/* HAVE_LINK_H defined in Bazel */
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 /* HAVE_MACH_MACH_H defined in Bazel */
 
diff --git a/utils/bazel/llvm_configs/config.h.cmake b/utils/bazel/llvm_configs/config.h.cmake
index ff30741c8f360a..f39d2d56d61e89 100644
--- a/utils/bazel/llvm_configs/config.h.cmake
+++ b/utils/bazel/llvm_configs/config.h.cmake
@@ -125,9 +125,6 @@
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
-/* Define to 1 if you have the <link.h> header file. */
-#cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}
 

[s-barannikov]

LGTM but I guess @Endilll should stamp it.