[libc] Add dladdr to dlfcn.h

[Caslyn]

A initial commit for #97929, this adds a stub implementation for dladdr and includes the definition for the DL_info type used as one of its arguments.

While the dladdr implementation relies on dynamic linker support, this patch will add its prototype in the generated dlfcn.h header so that it can be used by downstream platforms that have their own dladdr implementation.

[llvmbot]

@llvm/pr-subscribers-libc

Author: Caslyn Tonelli (Caslyn)

Changes

A initial commit for #97929, this adds a stub implementation for dladdr and includes the definition for the DL_info type used as one of its arguments.

While the dladdr implementation relies on dynamic linker support, this patch will add its prototype in the generated dlfcn.h header so that it can be used by downstream platforms that have their own dladdr implementation.

---

Full diff: https://github.com/llvm/llvm-project/pull/149872.diff

4 Files Affected:

• (modified) libc/include/dlfcn.yaml (+9)
• (added) libc/include/llvm-libc-types/DL_info.h (+19)
• (added) libc/src/dlfcn/dladdr.cpp (+19)
• (added) libc/src/dlfcn/dladdr.h (+20)

diff --git a/libc/include/dlfcn.yaml b/libc/include/dlfcn.yaml
index 28be34dbd95bd..ea4de6860e7ba 100644
--- a/libc/include/dlfcn.yaml
+++ b/libc/include/dlfcn.yaml
@@ -29,6 +29,8 @@ macros:
     standards:
       - gnu
     macro_value: "0x01000"
+types:
+  - type_name: DL_info
 functions:
   - name: dlclose
     standards:
@@ -55,3 +57,10 @@ functions:
     arguments:
       - type: void *__restrict
       - type: const char *__restrict
+  - name: dladdr
+    standards:
+      - POSIX
+    return_type: int
+    arguments:
+      - type: const void *
+      - type: DL_info *
diff --git a/libc/include/llvm-libc-types/DL_info.h b/libc/include/llvm-libc-types/DL_info.h
new file mode 100644
index 0000000000000..08dcba2c2945f
--- /dev/null
+++ b/libc/include/llvm-libc-types/DL_info.h
@@ -0,0 +1,19 @@
+//===-- Definition of DL_info type ----------------------------------------===//
+//
+// 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_TYPES_DL_INFO_H
+#define LLVM_LIBC_TYPES_DL_INFO_H
+
+typedef struct {
+  const char *dli_fname;
+  void *dli_fbase;
+  const char *dli_sname;
+  void *dli_saddr;
+} DL_info;
+
+#endif // LLVM_LIBC_TYPES_DL_INFO_H
diff --git a/libc/src/dlfcn/dladdr.cpp b/libc/src/dlfcn/dladdr.cpp
new file mode 100644
index 0000000000000..faaefcf161b54
--- /dev/null
+++ b/libc/src/dlfcn/dladdr.cpp
@@ -0,0 +1,19 @@
+//===-- 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"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+// TODO: https:// github.com/llvm/llvm-project/issues/97929
+LLVM_LIBC_FUNCTION(int, dladdr, (const void *, DL_info *)) { return -1; }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/dlfcn/dladdr.h b/libc/src/dlfcn/dladdr.h
new file mode 100644
index 0000000000000..a5f38973b7c02
--- /dev/null
+++ b/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
+
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int dladdr(const void *, DL_info *);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_DLFCN_DLADDR_H

[frobtech]

lgtm with the correct identifier names.