[llvm] [libc][bazel] Add Bazel rules for rand/srand functions. (PR #159617)

[Alexey Samsonov via llvm-commits]

https://github.com/vonosmas created https://github.com/llvm/llvm-project/pull/159617

These functions are unlikely to be used in the overlay mode (since they are stateful), but internal llvm-libc implementation is used in tests for FMA family of functions, so we need Bazel support for them to ensure proper test coverage.

>From 84568a45c8c757e148b45616b1bba949a623273e Mon Sep 17 00:00:00 2001
From: Alexey Samsonov <vonosmas at gmail.com>
Date: Thu, 18 Sep 2025 10:46:54 -0700
Subject: [PATCH] [libc][bazel] Add Bazel rules for rand/srand functions.

These functions are unlikely to be used in the overlay mode (since they
are stateful), but internal llvm-libc implementation is used in tests
for FMA family of functions, so we need Bazel support for them to ensure
proper test coverage.
---
 .../llvm-project-overlay/libc/BUILD.bazel     | 43 +++++++++++++++++++
 .../libc/test/src/stdlib/BUILD.bazel          |  9 ++++
 2 files changed, 52 insertions(+)

diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index cee92f2cc56c4..67c292f08be73 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -278,6 +278,14 @@ libc_support_library(
     hdrs = ["hdr/stdio_overlay.h"],
 )
 
+libc_support_library(
+    name = "hdr_stdlib_macros",
+    hdrs = ["hdr/stdlib_macros.h"],
+    deps = [
+        ":hdr_stdlib_overlay",
+    ],
+)
+
 libc_support_library(
     name = "hdr_stdlib_overlay",
     hdrs = ["hdr/stdlib_overlay.h"],
@@ -5066,6 +5074,41 @@ libc_function(
     ],
 )
 
+libc_support_library(
+    name = "rand_util",
+    srcs = ["src/stdlib/rand_util.cpp"],
+    hdrs = ["src/stdlib/rand_util.h"],
+    deps = [
+        ":__support_cpp_atomic",
+        ":__support_macros_attributes",
+        ":__support_macros_config",
+    ],
+)
+
+libc_function(
+    name = "rand",
+    srcs = ["src/stdlib/rand.cpp"],
+    hdrs = ["src/stdlib/rand.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":__support_threads_sleep",
+        ":hdr_stdlib_macros",
+        ":rand_util",
+    ],
+)
+
+libc_function(
+    name = "srand",
+    srcs = ["src/stdlib/srand.cpp"],
+    hdrs = ["src/stdlib/srand.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_config",
+        ":rand_util",
+    ],
+)
+
 libc_support_library(
     name = "str_from_util",
     hdrs = ["src/stdlib/str_from_util.h"],
diff --git a/utils/bazel/llvm-project-overlay/libc/test/src/stdlib/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/test/src/stdlib/BUILD.bazel
index ce92ca8caa6f4..fd4389e8c0579 100644
--- a/utils/bazel/llvm-project-overlay/libc/test/src/stdlib/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/test/src/stdlib/BUILD.bazel
@@ -159,6 +159,15 @@ libc_test(
     ],
 )
 
+libc_test(
+    name = "rand_test",
+    srcs = ["rand_test.cpp"],
+    deps = [
+        "//libc:rand",
+        "//libc:srand",
+    ],
+)
+
 libc_test_library(
     name = "strfrom_test_helper",
     hdrs = ["StrfromTest.h"],