[gn] Support for building compiler-rt builtins

[phosek]

Summary

This is support for building compiler-rt builtins, The library build
should be complete for a subset of supported platforms, but not all
CMake options have been replicated in GN.

We always use the just built compiler to build all the runtimes, which
is equivalent to the CMake runtimes build. This simplifies the build
configuration because we don't need to support arbitrary host compiler
and can always assume the latest Clang. With GN's toolchain support,
this is significantly more efficient than the CMake runtimes build.

[thakis]

lgtm except for minor comments:

llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn

3

llvm/utils/gn/gn.py help label: "Stylistically, we prefer to use absolute paths for all non-file-local references"

llvm/utils/gn/secondary/compiler-rt/lib/builtins/BUILD.gn

30

Edit llvm/utils/gn/build/sync_source_lists_from_cmake.py and modify gn_cpp_re and cmake_cpp_re to contain |c after cpp and make sure the script is still happy. You probably have to move a few closing parens in compiler-rt/lib/builtins/CMakeLists.txt to the next line (which is by far the more common style in LLVM's cmake, so this will make the cmake build more consistent too).

Hm, looking at that file, we might want to add |S there too.

[thakis]

Thanks! lgtm with the comment for the one one-line sources line as discussed.

compiler-rt/lib/builtins/CMakeLists.txt

154 ↗

(On Diff #193943)

(the more common style is to indent the ) by two. unless you're being consistent with other places in this file, consider indenting the closing parens)

llvm/utils/gn/secondary/compiler-rt/lib/builtins/BUILD.gn

366

ppc64 too, or are these 32-bit?

[phosek]

compiler-rt/lib/builtins/CMakeLists.txt

154 ↗

(On Diff #193943)

Other sets in this file already used this style so I was trying to be consistent with those. Do you want me to reformat all of them?

[thakis]

compiler-rt/lib/builtins/CMakeLists.txt

154 ↗

(On Diff #193943)

No, it's fine then.

llvm/utils/gn/secondary/BUILD.gn

 import("//clang/lib/ARCMigrate/enable.gni")
 import("//clang/lib/StaticAnalyzer/Frontend/enable.gni")
 import("//llvm/utils/gn/build/toolchain/compiler.gni")
 
 group("default") {
   deps = [
     "//clang-tools-extra/test",
     "//clang/test",
     "//lld/test",
     "//llvm/test",
   ]
+  if (current_os == "linux") {
+    deps += [ "//compiler-rt" ]
+  }
   if (current_os == "linux" || current_os == "android") {
     deps += [ "//compiler-rt/test/hwasan" ]
   }
 
   testonly = true
 }
 
 # Symlink handling.

llvm/utils/gn/secondary/compiler-rt/BUILD.gn

+group("compiler-rt") {
+  deps = [
+    "lib(//llvm/utils/gn/build/toolchain:stage2_unix)",
+  ]
+}

llvm/utils/gn/secondary/compiler-rt/lib/BUILD.gn

+group("lib") {
+  deps = [
+    "builtins",
+  ]
+}

llvm/utils/gn/secondary/compiler-rt/lib/builtins/BUILD.gn

+import("//compiler-rt/target.gni")
+import("//llvm/utils/gn/build/buildflags.gni")
+
+declare_args() {
+  # Skip the atomic builtin (these should normally be provided by a shared library)
+  compiler_rt_exclude_atomic_builtin = true
+
+  # Compile builtins for baremetal.
+  compiler_rt_baremetal_build = false
+}
+
+static_library("builtins") {
+  output_dir = crt_current_out_dir
+  output_name = "clang_rt.builtins-$crt_current_target"
+  complete_static_lib = true
+  cflags = [
+    "-fPIC",
+    "-fno-builtin",
+  ]
+  if (target_os != "android") {
+    cflags += [ "-fvisibility=hidden" ]
+  }
+  if (!is_debug) {
+    cflags += [ "-fomit-frame-pointer" ]
+  }
+  cflags_c = [ "-std=c11" ]
+  configs -= [ "//llvm/utils/gn/build:thin_archive" ]
+
+  sources = [
+    "absvdi2.c",
+    "absvsi2.c",
+    "absvti2.c",
+    "adddf3.c",
+    "addsf3.c",
+    "addtf3.c",
+    "addvdi3.c",
+    "addvsi3.c",
+    "addvti3.c",
+    "apple_versioning.c",
+    "ashldi3.c",
+    "ashlti3.c",
+    "ashrdi3.c",
+    "ashrti3.c",
+    "bswapdi2.c",
+    "bswapsi2.c",
+    "clzdi2.c",
+    "clzsi2.c",
+    "clzti2.c",
+    "cmpdi2.c",
+    "cmpti2.c",
+    "comparedf2.c",
+    "comparesf2.c",
+    "ctzdi2.c",
+    "ctzsi2.c",
+    "ctzti2.c",
+    "divdc3.c",
+    "divdf3.c",
+    "divdi3.c",
+    "divmoddi4.c",
+    "divmodsi4.c",
+    "divsc3.c",
+    "divsf3.c",
+    "divsi3.c",
+    "divtc3.c",
+    "divti3.c",
+    "divtf3.c",
+    "extendsfdf2.c",
+    "extendhfsf2.c",
+    "ffsdi2.c",
+    "ffssi2.c",
+    "ffsti2.c",
+    "fixdfdi.c",
+    "fixdfsi.c",
+    "fixdfti.c",
+    "fixsfdi.c",
+    "fixsfsi.c",
+    "fixsfti.c",
+    "fixunsdfdi.c",
+    "fixunsdfsi.c",
+    "fixunsdfti.c",
+    "fixunssfdi.c",
+    "fixunssfsi.c",
+    "fixunssfti.c",
+    "floatdidf.c",
+    "floatdisf.c",
+    "floatsidf.c",
+    "floatsisf.c",
+    "floattidf.c",
+    "floattisf.c",
+    "floatundidf.c",
+    "floatundisf.c",
+    "floatunsidf.c",
+    "floatunsisf.c",
+    "floatuntidf.c",
+    "floatuntisf.c",
+    "int_util.c",
+    "lshrdi3.c",
+    "lshrti3.c",
+    "moddi3.c",
+    "modsi3.c",
+    "modti3.c",
+    "muldc3.c",
+    "muldf3.c",
+    "muldi3.c",
+    "mulodi4.c",
+    "mulosi4.c",
+    "muloti4.c",
+    "mulsc3.c",
+    "mulsf3.c",
+    "multi3.c",
+    "multf3.c",
+    "mulvdi3.c",
+    "mulvsi3.c",
+    "mulvti3.c",
+    "negdf2.c",
+    "negdi2.c",
+    "negsf2.c",
+    "negti2.c",
+    "negvdi2.c",
+    "negvsi2.c",
+    "negvti2.c",
+    "os_version_check.c",
+    "paritydi2.c",
+    "paritysi2.c",
+    "parityti2.c",
+    "popcountdi2.c",
+    "popcountsi2.c",
+    "popcountti2.c",
+    "powidf2.c",
+    "powisf2.c",
+    "powitf2.c",
+    "subdf3.c",
+    "subsf3.c",
+    "subvdi3.c",
+    "subvsi3.c",
+    "subvti3.c",
+    "subtf3.c",
+    "trampoline_setup.c",
+    "truncdfhf2.c",
+    "truncdfsf2.c",
+    "truncsfhf2.c",
+    "ucmpdi2.c",
+    "ucmpti2.c",
+    "udivdi3.c",
+    "udivmoddi4.c",
+    "udivmodsi4.c",
+    "udivmodti4.c",
+    "udivsi3.c",
+    "udivti3.c",
+    "umoddi3.c",
+    "umodsi3.c",
+    "umodti3.c",
+  ]
+
+  if (target_os != "fuchsia") {
+    sources += [
+      "emutls.c ",
+      "enable_execute_stack.c",
+      "eprintf.c",
+    ]
+  }
+
+  if (target_os != "fuchsia" && !compiler_rt_baremetal_build) {
+    sources += [ "clear_cache.c" ]
+  }
+
+  if (target_os == "mac") {
+    sources += [
+      "atomic_flag_clear.c",
+      "atomic_flag_clear_explicit.c",
+      "atomic_flag_test_and_set.c",
+      "atomic_flag_test_and_set_explicit.c",
+      "atomic_signal_fence.c",
+      "atomic_thread_fence.c",
+    ]
+  }
+
+  if (target_cpu == "x86" || target_cpu == "x64") {
+    sources += [
+      "cpu_model.c",
+      "divxc3.c",
+      "fixxfdi.c",
+      "fixxfti.c",
+      "fixunsxfdi.c",
+      "fixunsxfsi.c",
+      "fixunsxfti.c",
+      "floatdixf.c",
+      "floattixf.c",
+      "floatundixf.c",
+      "floatuntixf.c",
+      "mulxc3.c",
+      "powixf2.c",
+    ]
+
+    if (target_os == "win") {
+      # Use C versions of functions when building on MSVC
+      # MSVC's assembler takes Intel syntax, not AT&T syntax.
+      # Also use only MSVC compilable builtin implementations.
+      sources += [
+        "x86_64/floatdidf.c",
+        "x86_64/floatdisf.c",
+        "x86_64/floatdixf.c",
+      ]
+    }
+  }
+
+  if (target_cpu == "arm") {
+    sources += [
+      "arm/bswapdi2.S",
+      "arm/bswapsi2.S",
+      "arm/clzdi2.S",
+      "arm/clzsi2.S",
+      "arm/comparesf2.S",
+      "arm/divmodsi4.S",
+      "arm/divsi3.S",
+      "arm/modsi3.S",
+      "arm/sync_fetch_and_add_4.S",
+      "arm/sync_fetch_and_add_8.S",
+      "arm/sync_fetch_and_and_4.S",
+      "arm/sync_fetch_and_and_8.S",
+      "arm/sync_fetch_and_max_4.S",
+      "arm/sync_fetch_and_max_8.S",
+      "arm/sync_fetch_and_min_4.S",
+      "arm/sync_fetch_and_min_8.S",
+      "arm/sync_fetch_and_nand_4.S",
+      "arm/sync_fetch_and_nand_8.S",
+      "arm/sync_fetch_and_or_4.S",
+      "arm/sync_fetch_and_or_8.S",
+      "arm/sync_fetch_and_sub_4.S",
+      "arm/sync_fetch_and_sub_8.S",
+      "arm/sync_fetch_and_umax_4.S",
+      "arm/sync_fetch_and_umax_8.S",
+      "arm/sync_fetch_and_umin_4.S",
+      "arm/sync_fetch_and_umin_8.S",
+      "arm/sync_fetch_and_xor_4.S",
+      "arm/sync_fetch_and_xor_8.S",
+      "arm/udivmodsi4.S",
+      "arm/udivsi3.S",
+      "arm/umodsi3.S",
+    ]
+  }
+
+  if (target_cpu == "arm64") {
+    sources += [
+      "comparetf2.c",
+      "extenddftf2.c",
+      "extendsftf2.c",
+      "fixtfdi.c",
+      "fixtfsi.c",
+      "fixtfti.c",
+      "fixunstfdi.c",
+      "fixunstfsi.c",
+      "fixunstfti.c",
+      "floatditf.c",
+      "floatsitf.c",
+      "floattitf.c",
+      "floatunditf.c",
+      "floatunsitf.c",
+      "floatuntitf.c",
+      "multc3.c",
+      "trunctfdf2.c",
+      "trunctfsf2.c",
+    ]
+  }
+
+  if (!compiler_rt_exclude_atomic_builtin) {
+    sources += [ "atomic.c" ]
+  }
+}