[libc] Add link.h and elf.h placeholder

libc/config/linux/aarch64/entrypoints.txt

@@ -18,6 +18,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.ctype.toupper
 
     # dlfcn.h entrypoints
+    libc.src.dlfcn.dladdr
     libc.src.dlfcn.dlclose
     libc.src.dlfcn.dlerror
     libc.src.dlfcn.dlopen
@@ -32,6 +33,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # link.h entrypoints
+    libc.src.link.dl_iterate_phdr
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min

libc/config/linux/api.td

@@ -308,3 +308,16 @@ def SearchAPI : PublicAPI<"search.h"> {
 def SysStatvfsAPI : PublicAPI<"sys/statvfs.h"> {
   let Types = ["fsblkcnt_t", "fsfilcnt_t", "struct statvfs"];
 }
+
+def LinkAPI : PublicAPI<"link.h"> {
+  let Types = [
+    "struct dl_phdr_info",
+    "__dl_iterate_phdr_callback_t"
+  ];
+}
+
+def DlfcnAPI : PublicAPI<"dlfcn.h"> {
+  let Types = [
+    "Dl_info"
+  ];
+}

libc/config/linux/x86_64/entrypoints.txt

@@ -18,6 +18,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.ctype.toupper
 
     # dlfcn.h entrypoints
+    libc.src.dlfcn.dladdr
     libc.src.dlfcn.dlclose
     libc.src.dlfcn.dlerror
     libc.src.dlfcn.dlopen
@@ -32,6 +33,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.fcntl.open
     libc.src.fcntl.openat
 
+    # link.h entrypoints
+    libc.src.link.dl_iterate_phdr
+
     # sched.h entrypoints
     libc.src.sched.sched_get_priority_max
     libc.src.sched.sched_get_priority_min

libc/include/elf.h.def

@@ -0,0 +1,14 @@
+//===-- C standard library header elf.h -----------------------------------===//
+//
+// 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_ELF_H
+#define LLVM_LIBC_ELF_H
+
+#include "llvm-libc-macros/elf-macros.h"
+
+#endif // LLVM_LIBC_ELF_H

libc/include/link.h.def

@@ -0,0 +1,16 @@
+//===-- C standard library header link.h ----------------------------------===//
+//
+// 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_LINK_H
+#define LLVM_LIBC_LINK_H
+
+#include "llvm-libc-macros/link-macros.h"
+
+%%public_api()
+
+#endif // LLVM_LIBC_LINK_H

libc/spec/linux.td

@@ -3,6 +3,9 @@ def StructEpollEventPtr : PtrType<StructEpollEvent>;
 
 def StructEpollData : NamedType<"struct epoll_data">;
 
+def StructDlPhdrInfo : NamedType<"struct dl_phdr_info">;
+def DlIteratePhdrCallback : NamedType<"__dl_iterate_phdr_callback_t">;
+
 def Linux : StandardSpec<"Linux"> {
   HeaderSpec Errno = HeaderSpec<
       "errno.h",
@@ -264,8 +267,35 @@ def Linux : StandardSpec<"Linux"> {
       ]
   >;
 
+  HeaderSpec Link = HeaderSpec<
+     "link.h",
+      [], // Macros
+      [StructDlPhdrInfo, DlIteratePhdrCallback], // Types
+      [], // Enumerations
+      [
+        FunctionSpec<
+          "dl_iterate_phdr",
+          RetValSpec<IntType>,
+          [
+            ArgSpec<DlIteratePhdrCallback>,
+            ArgSpec<VoidPtr>
+          ]
+        >,
+      ]  // Functions
+  >;
+
+  HeaderSpec Elf = HeaderSpec<
+     "elf.h",
+      [], // Macros
+      [], // Types
+      [], // Enumerations
+      []  // Functions
+  >;
+
   let Headers = [
+    Elf,
     Errno,
+    Link,
     SysEpoll,
     SysMMan,
     SysPrctl,

libc/spec/posix.td

@@ -21,6 +21,9 @@ def PThreadOnceT : NamedType<"pthread_once_t">;
 def PThreadOnceTPtr : PtrType<PThreadOnceT>;
 def PThreadOnceCallback : NamedType<"__pthread_once_func_t">;
 
+def DlInfo : NamedType<"Dl_info">;
+def DlInfoPtr : PtrType<DlInfo>;
+
 def InoT : NamedType<"ino_t">;
 def UidT : NamedType<"uid_t">;
 def GidT : NamedType<"gid_t">;
@@ -230,9 +233,14 @@ def POSIX : StandardSpec<"POSIX"> {
       Macro<"RTLD_GLOBAL">,
       Macro<"RTLD_LOCAL">,
     ],
-    [],  // Types
+    [DlInfo],  // Types
     [], // Enumerations
     [
+      FunctionSpec<
+          "dladdr",
+          RetValSpec<IntType>,
+          [ArgSpec<ConstVoidPtr>, ArgSpec<DlInfoPtr>]
+      >,
       FunctionSpec<
           "dlclose",
           RetValSpec<IntType>,

libc/src/CMakeLists.txt

@@ -5,6 +5,7 @@ add_subdirectory(dlfcn)
 add_subdirectory(errno)
 add_subdirectory(fenv)
 add_subdirectory(inttypes)
+add_subdirectory(link)
 add_subdirectory(math)
 add_subdirectory(stdbit)
 add_subdirectory(stdfix)

libc/src/dlfcn/CMakeLists.txt

@@ -1,3 +1,14 @@
+add_entrypoint_object(
+  dladdr
+  SRCS
+    dladdr.cpp
+  HDRS
+    dladdr.h
+  DEPENDS
+    libc.include.dlfcn
+    libc.src.errno.errno
+)
+
 add_entrypoint_object(
   dlclose
   SRCS

libc/src/dlfcn/dladdr.cpp

@@ -0,0 +1,18 @@
+//===-- Implementation of dladdr -----------------------------------------===//
+//
+// 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 "dladdr.h"
+
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+// TODO(@izaakschroeder): https://github.com/llvm/llvm-project/issues/97929
+LLVM_LIBC_FUNCTION(int, dladdr, (const void *, Dl_info *)) { return 0; }
+
+} // namespace LIBC_NAMESPACE

libc/src/dlfcn/dladdr.h

@@ -0,0 +1,20 @@
+//===-- Implementation header of dladdr ------------------------*- 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_DLFCN_DLADDR_H
+#define LLVM_LIBC_SRC_DLFCN_DLADDR_H
+
+namespace LIBC_NAMESPACE {
+
+#include "include/llvm-libc-types/Dl_info.h"
+
+int dladdr(const void *, Dl_info *);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_DLFCN_DLADDR_H

libc/src/link/CMakeLists.txt

@@ -0,0 +1,9 @@
+add_entrypoint_object(
+  dl_iterate_phdr
+  SRCS
+    dl_iterate_phdr.cpp
+  HDRS
+    dl_iterate_phdr.h
+  DEPENDS
+    libc.src.__support.common
+)

libc/src/link/dl_iterate_phdr.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of dl_iterate_phdr ---------------------------------===//
+//
+// 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 "dl_iterate_phdr.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+// TODO(@izaakschroeder): https://github.com/llvm/llvm-project/issues/97928
+LLVM_LIBC_FUNCTION(int, dl_iterate_phdr,
+                   (__dl_iterate_phdr_callback_t, void *)) {
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/link/dl_iterate_phdr.h

@@ -0,0 +1,20 @@
+//===-- Implementation header for dl_iterate_phdr ---------------*- 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_LINK_DL_ITERATE_PHDR_H
+#define LLVM_LIBC_SRC_LINK_DL_ITERATE_PHDR_H
+
+namespace LIBC_NAMESPACE {
+
+#include "include/llvm-libc-types/__dl_iterate_phdr_callback_t.h"
+
+int dl_iterate_phdr(__dl_iterate_phdr_callback_t, void *);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_LINK_DL_ITERATE_PHDR_H