Update LLVM to pick up new compiler-rt build rules (#6023)

This removes the need for a patch and improves on the quality of the
rules significantly. A follow-up PR will use this to apply a number of
fixes to how we build the runtimes.

MODULE.bazel

@@ -103,19 +103,19 @@ bazel_dep(name = "zstd", version = "1.5.7", repo_name = "llvm_zstd")
 
 # We pin to specific upstream commits and try to track top-of-tree reasonably
 # closely rather than pinning to a specific release.
-# HEAD as of 2025-08-20.
-llvm_project_version = "a6da68ed36d7ecb9edf00262d2a2c1129689399f"
+# HEAD as of 2025-09-07.
+llvm_project_version = "c000c9e4bf737c1cc0e5c7b435b24ea73d21ee05"
 
 # Load a repository for the raw llvm-project, pre-overlay.
 http_archive(
     name = "llvm-raw",
     build_file_content = "# empty",
+    integrity = "sha256-6URudXFgqoCuQI4hbb7AlN4Wj7WzLHFB4AWGjUV0UAI=",
     patch_args = ["-p1"],
     patches = [
         "@carbon//bazel/llvm_project:0001_Patch_for_mallinfo2_when_using_Bazel_build_system.patch",
         "@carbon//bazel/llvm_project:0002_Added_Bazel_build_for_compiler_rt_fuzzer.patch",
         "@carbon//bazel/llvm_project:0003_Comment_out_unloaded_proto_library_dependencies.patch",
-        "@carbon//bazel/llvm_project:0004_Introduce_filegroups_for_compiler_rt_builtins_runtime.patch",
     ],
     strip_prefix = "llvm-project-{0}".format(llvm_project_version),
     urls = ["https://github.com/llvm/llvm-project/archive/{0}.tar.gz".format(llvm_project_version)],

bazel/llvm_project/0004_Introduce_filegroups_for_compiler_rt_builtins_runtime.patch

@@ -1,194 +0,0 @@
-From 19d5d9913778ca95da272f41c5916907154a5e73 Mon Sep 17 00:00:00 2001
-From: Chandler Carruth <chandlerc@gmail.com>
-Date: Thu, 24 Apr 2025 05:03:43 +0000
-Subject: [PATCH] Introduce filegroups for compiler-rt builtins runtimes
-
-These filegroups allow downstream projects to package and build
-customized runtime libraries.
-
-The filegroups work hard to use globs and a careful structuring to
-create the structured breakdown of sources needed to target different
-architectures and platforms without having to maintain a complete
-parallel list of sources from CMake.
----
- .../compiler-rt/BUILD.bazel                   | 167 ++++++++++++++++++
- 1 file changed, 167 insertions(+)
-
-diff --git a/utils/bazel/llvm-project-overlay/compiler-rt/BUILD.bazel b/utils/bazel/llvm-project-overlay/compiler-rt/BUILD.bazel
-index 6a5a89fdee40..7d158f0c13f2 100644
---- a/utils/bazel/llvm-project-overlay/compiler-rt/BUILD.bazel
-+++ b/utils/bazel/llvm-project-overlay/compiler-rt/BUILD.bazel
-@@ -128,3 +128,170 @@ cc_library(
-     ],
-     includes = ["lib/fuzzer"],
- )
-+
-+BUILTINS_CRTBEGIN_SRCS = ["lib/builtins/crtbegin.c"]
-+
-+filegroup(
-+    name = "builtins_crtbegin_src",
-+    srcs = BUILTINS_CRTBEGIN_SRCS,
-+)
-+
-+BUILTINS_CRTEND_SRCS = ["lib/builtins/crtend.c"]
-+
-+filegroup(
-+    name = "builtins_crtend_src",
-+    srcs = BUILTINS_CRTEND_SRCS,
-+)
-+
-+# Note that while LLVM's CompilerRT provides a few hosted sources, we don't
-+# currently build them:
-+#
-+# - `emutls.c`: Unclear we need to support targets with software emulated
-+#   TLS rather than hardware support.
-+# - `enable_execute_stack.c`: Used to implement support for a builtin that
-+#   marks part of the stack as *executable* to support the GCC extension of
-+#   nested functions. This extension was never implemented in Clang, and is
-+#   generally considered a security issue to include. We expect to be able
-+#   to avoid even linking the support code for this into binaries at this
-+#   point.
-+# - `eprintf.c`: This provided a legacy `__eprintf` builtin used by old
-+#   versions of `assert.h` in its macros, but does not appear to be needed
-+#   when building with modern versions of this header.
-+BUILTINS_HOSTED_SRCS = [
-+    "lib/builtins/emutls.c",
-+    "lib/builtins/enable_execute_stack.c",
-+    "lib/builtins/eprintf.c",
-+]
-+
-+filegroup(
-+    name = "builtins_hosted_srcs",
-+    srcs = BUILTINS_HOSTED_SRCS,
-+)
-+
-+BUILTINS_BF16_SRCS_PATTERNS = [
-+    # `bf` marks 16-bit Brain floating-point number builtins.
-+    "lib/builtins/*bf*.c",
-+]
-+
-+filegroup(
-+    name = "builtins_bf16_srcs",
-+    srcs = glob(BUILTINS_BF16_SRCS_PATTERNS),
-+)
-+
-+BUILTINS_X86_FP80_SRCS_PATTERNS = [
-+    # `xc` marks 80-bit complex number builtins.
-+    "lib/builtins/*xc*.c",
-+
-+    # `xf` marks 80-bit floating-point builtins.
-+    "lib/builtins/*xf*.c",
-+]
-+
-+filegroup(
-+    name = "builtins_x86_fp80_srcs",
-+    srcs = glob(
-+        BUILTINS_X86_FP80_SRCS_PATTERNS,
-+        exclude = BUILTINS_BF16_SRCS_PATTERNS,
-+    ),
-+)
-+
-+BUILTINS_TF_SRCS_PATTERNS = [
-+    # `tc` marks 128-bit complex number builtins.
-+    "lib/builtins/*tc*.c",
-+
-+    # `tf` marks 128-bit floating-point builtins.
-+    "lib/builtins/*tf*.c",
-+]
-+
-+BUILTINS_TF_EXCLUDES = (
-+    BUILTINS_HOSTED_SRCS +
-+    BUILTINS_BF16_SRCS_PATTERNS +
-+    BUILTINS_X86_FP80_SRCS_PATTERNS
-+)
-+
-+filegroup(
-+    name = "builtins_tf_srcs",
-+    srcs = glob(
-+        BUILTINS_TF_SRCS_PATTERNS,
-+        exclude = BUILTINS_TF_EXCLUDES,
-+    ),
-+)
-+
-+BUILTINS_MACOS_ATOMIC_SRCS_PATTERNS = [
-+    "lib/builtins/atomic_*.c",
-+]
-+
-+filegroup(
-+    name = "builtins_macos_atomic_srcs",
-+    srcs = glob(BUILTINS_MACOS_ATOMIC_SRCS_PATTERNS),
-+)
-+
-+filegroup(
-+    name = "builtins_aarch64_srcs",
-+    srcs = [
-+        "lib/builtins/cpu_model/aarch64.c",
-+        "lib/builtins/cpu_model/aarch64.h",
-+    ] + glob(
-+        [
-+            "lib/builtins/cpu_model/AArch64*.inc",
-+            "lib/builtins/cpu_model/aarch64/**/*.inc",
-+            "lib/builtins/aarch64/*.S",
-+            "lib/builtins/aarch64/*.c",
-+        ],
-+        exclude = [
-+            # This file isn't intended to directly compile, but to be used to
-+            # generate a collection of outline atomic helpers.
-+            # TODO: Add support for generating the sources for these helpers if
-+            # there are users that need this functionality from the builtins
-+            # library.
-+            "lib/builtins/aarch64/lse.S",
-+        ],
-+    ),
-+)
-+
-+filegroup(
-+    name = "builtins_x86_arch_srcs",
-+    srcs = [
-+        "lib/builtins/cpu_model/x86.c",
-+        "lib/builtins/i386/fp_mode.c",
-+    ],
-+)
-+
-+filegroup(
-+    name = "builtins_x86_64_srcs",
-+    srcs = glob([
-+        "lib/builtins/x86_64/*.c",
-+        "lib/builtins/x86_64/*.S",
-+    ]),
-+)
-+
-+filegroup(
-+    name = "builtins_i386_srcs",
-+    srcs = glob(
-+        [
-+            "lib/builtins/i386/*.c",
-+            "lib/builtins/i386/*.S",
-+        ],
-+        exclude = [
-+            # This file is used for both i386 and x86_64.
-+            "lib/builtins/i386/fp_mode.c",
-+        ],
-+    ),
-+)
-+
-+filegroup(
-+    name = "builtins_generic_srcs",
-+    srcs = ["lib/builtins/cpu_model/cpu_model.h"] + glob(
-+        [
-+            "lib/builtins/*.c",
-+            "lib/builtins/*.h",
-+            "lib/builtins/*.inc",
-+        ],
-+        exclude = (
-+            BUILTINS_CRTBEGIN_SRCS +
-+            BUILTINS_CRTEND_SRCS +
-+            BUILTINS_TF_EXCLUDES +
-+            BUILTINS_TF_SRCS_PATTERNS +
-+            BUILTINS_MACOS_ATOMIC_SRCS_PATTERNS
-+        ),
-+    ),
-+)
--- 
-2.49.0.850.g28803427d3-goog
-