[llvm] [Bazel] Export compiler-rt builtins sources (PR #157200)

[Aaron Siddhartha Mondal via llvm-commits]

================
@@ -113,3 +113,305 @@ cc_library(
         ":orc_rt_common_headers",
     ],
 )
+
+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,
+)
+
+BUILTINS_HOSTED_SRCS = [
+    "lib/builtins/clear_cache.c",
+    "lib/builtins/emutls.c",
+    "lib/builtins/enable_execute_stack.c",
+    "lib/builtins/eprintf.c",
+]
+
+# Source files in the builtins library that build on top of libc and are only
+# appropriate in hosted environments.
+filegroup(
+    name = "builtins_hosted_srcs",
+    srcs = BUILTINS_HOSTED_SRCS,
+)
+
+BUILTINS_BF16_SRCS_PATTERNS = [
+    "lib/builtins/*bf*.c",
+]
+
+# Source files for the 16-bit Brain floating-point number builtins.
+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",
+]
+
+# Source files for the 80-bit floating-point and complex number builtins.
+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
+)
+
+# Source files for the 128-bit floating-point and complex number builtins.
+filegroup(
+    name = "builtins_tf_srcs",
+    srcs = glob(
+        BUILTINS_TF_SRCS_PATTERNS,
+        exclude = BUILTINS_TF_EXCLUDES,
+    ),
+)
+
+BUILTNS_ATOMICS_SRCS = ["lib/builtins/atomic.c"]
+
+filegroup(
+    name = "builtins_atomics_srcs",
+    srcs = BUILTNS_ATOMICS_SRCS + ["lib/builtins/assembly.h"],
+)
+
+BUILTINS_MACOS_ATOMIC_SRCS_PATTERNS = [
+    "lib/builtins/atomic_*.c",
+]
+
+# Source files for macOS atomic builtins.
+filegroup(
+    name = "builtins_macos_atomic_srcs",
+    srcs = glob(BUILTINS_MACOS_ATOMIC_SRCS_PATTERNS),
+)
+
+# Apple-platform specific SME source file.
+filegroup(
+    name = "builtins_aarch64_apple_sme_srcs",
+    srcs = ["lib/builtins/aarch64/arm_apple_sme_abi.s"],
+)
+
+# Non-Apple platform SME sources. These sources assume function
+# multi-versioning, `-fno-builtin`, `__ARM_UNALIGNED` feature support, and FP
+# availability. Other configurations will need to add a new filegroup if
+# desired.
+filegroup(
+    name = "builtins_aarch64_sme_srcs",
+    srcs = [
+        "lib/builtins/aarch64/sme-abi.S",
+        "lib/builtins/aarch64/sme-abi-assert.c",
+    ] + glob(["lib/builtins/aarch64/sme-libc-opt-*.S"]),
+)
+
+# A list of (pat, size, model) tuples for AArch64's outline atomics.
+AARCH64_OUTLINE_ATOMICS = [
+    (pat, size, model)
+    for pat in [
+        "cas",
+        "swp",
+        "ldadd",
+        "ldclr",
+        "ldeor",
+        "ldset",
+    ]
+    for size in [
+        "1",
+        "2",
+        "4",
+        "8",
+        "16",
+    ]
+    for model in [
+        "1",
+        "2",
+        "3",
+        "4",
+    ]
+    if pat == "cas" or size != "16"
+]
+
+AARCH64_OUTLINE_ATOMICS_FMT = "lib/builtins/aarch64/outline_atomic_{0}{1}_{2}.S"
+
+# lse.S is compiled multiple times with different macros as the input. Model
+# this as a genrule producing individual files with the macros at the start.
+[[genrule(
+    name = "builtins_aarch64_outline_atomic_" + pat + size + "_" + model,
+    srcs = ["lib/builtins/aarch64/lse.S"],
+    outs = [AARCH64_OUTLINE_ATOMICS_FMT.format(pat, size, model)],
+    cmd = (
+        "echo '#define L_" + pat + "' >> $(OUTS) && " +
+        "echo '#define SIZE " + size + "' >> $(OUTS) && " +
+        "echo '#define MODEL " + model + "' >> $(OUTS) && " +
+        "cat $(SRCS) >> $(OUTS)"
+    ),
+)] for (pat, size, model) in AARCH64_OUTLINE_ATOMICS]
----------------
aaronmondal wrote:

Ah yeah I did mean to keep the `.S` files but to use the preprocessor so that the defines don't somehow collide with someone that includes these files or the `assembly.h` file. (The `lse.S` file doesn't seem to have include guards).

But tbh this seems more like something that might make more sense to change on the CMake side first if at all. Once the rule-based cc_toolchains in rules_cc get a bit more stable/widely used it might make sense to revisit this if those make it easier to get just a preprocessor, but at the moment just the echos seem like the better option if this works for current downstream usage already.

The bazel_skylib's template expansion isn't really an option here either as the usage of these macros is not something that can easily be substituted in via the template engine.

So I think this is good the way it is 👍 

https://github.com/llvm/llvm-project/pull/157200