[gn build] Add some llvm/tools: llvm-exegesis, llvm-extract, llvm-link

[thakis]

Summary

Also add build file for dependency llvm/lib/ExecutionEngine/MCJIT.

The exegesis stuff is pretty hairy and knows a lot about Target internals (in general, not specifically in the GN build). I put the llvm-tblgen -gen-exegesis call in llvm/tools/llvm-exegesis/lib/X86, instead of in llvm/lib/Target/X86 where it is in CMake land, and asked on D52932 why it's in that place in the CMake build.

Needed for check-llvm.

[phosek]

LGTM

llvm/utils/gn/secondary/BUILD.gn

 import("//clang/lib/ARCMigrate/enable.gni")
 import("//clang/lib/StaticAnalyzer/Frontend/enable.gni")
 
 group("default") {
   deps = [
     "//clang/test",
     "//lld/test",
+    "//llvm/tools/llvm-exegesis",
+    "//llvm/tools/llvm-extract",
+    "//llvm/tools/llvm-link",
     "//llvm/tools/llvm-mca",
     "//llvm/tools/llvm-mt",
     "//llvm/tools/llvm-rc",
     "//llvm/tools/llvm-rtdyld",
     "//llvm/tools/llvm-size",
     "//llvm/tools/llvm-split",
     "//llvm/tools/llvm-strings",
     "//llvm/tools/llvm-undname",

llvm/utils/gn/secondary/llvm/lib/ExecutionEngine/MCJIT/BUILD.gn

+static_library("MCJIT") {
+  output_name = "LLVMMCJIT"
+  deps = [
+    "//llvm/lib/ExecutionEngine",
+    "//llvm/lib/ExecutionEngine/RuntimeDyld",
+    "//llvm/lib/IR",
+    "//llvm/lib/Object",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target",
+  ]
+  sources = [
+    "MCJIT.cpp",
+  ]
+}

llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/BUILD.gn

+executable("llvm-exegesis") {
+  deps = [
+    "lib",
+    "//llvm/lib/CodeGen",
+    "//llvm/lib/ExecutionEngine",
+    "//llvm/lib/ExecutionEngine/MCJIT",
+    "//llvm/lib/MC",
+    "//llvm/lib/Object",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target:NativeTarget",
+  ]
+  sources = [
+    "llvm-exegesis.cpp",
+  ]
+}

llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/BUILD.gn

+import("//llvm/lib/Target/targets.gni")
+
+static_library("lib") {
+  output_name = "LLVMExegesis"
+  deps = [
+    "//llvm/lib/Analysis",
+    "//llvm/lib/CodeGen",
+    "//llvm/lib/ExecutionEngine",
+    "//llvm/lib/ExecutionEngine/MCJIT",
+    "//llvm/lib/IR",
+    "//llvm/lib/MC",
+    "//llvm/lib/Object",
+    "//llvm/lib/ObjectYAML",
+    "//llvm/lib/Support",
+  ]
+  sources = [
+    "Analysis.cpp",
+    "Assembler.cpp",
+    "BenchmarkResult.cpp",
+    "BenchmarkRunner.cpp",
+    "Clustering.cpp",
+    "CodeTemplate.cpp",
+    "Latency.cpp",
+    "LlvmState.cpp",
+    "MCInstrDescView.cpp",
+    "PerfHelper.cpp",
+    "RegisterAliasing.cpp",
+    "RegisterValue.cpp",
+    "SnippetGenerator.cpp",
+    "Target.cpp",
+    "Uops.cpp",
+  ]
+
+  # FIXME: Add this once llvm/lib/Target/AArch64 exists.
+  #if (llvm_build_AArch64) {
+  #  deps += [ "AArch64" ]
+  #}
+  if (llvm_build_X86) {
+    deps += [ "X86" ]
+  }
+}

llvm/utils/gn/secondary/llvm/tools/llvm-exegesis/lib/X86/BUILD.gn

+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("X86GenExegesis") {
+  args = [ "-gen-exegesis" ]
+  td_file = "//llvm/lib/Target/X86/X86.td"
+}
+
+static_library("X86") {
+  output_name = "LLVMExegesisX86"
+  deps = [
+    ":X86GenExegesis",
+
+    # Exegesis reaches inside the Target/X86 tablegen internals and must
+    # depend on this Target/X86-internal build target.
+    "//llvm/lib/Target/X86/MCTargetDesc",
+  ]
+  sources = [
+    "Target.cpp",
+  ]
+  include_dirs = [ "//llvm/lib/Target/X86" ]
+}

llvm/utils/gn/secondary/llvm/tools/llvm-extract/BUILD.gn

+executable("llvm-extract") {
+  deps = [
+    "//llvm/lib/Bitcode/Writer",
+    "//llvm/lib/IR",
+    "//llvm/lib/IRReader",
+    "//llvm/lib/Support",
+    "//llvm/lib/Transforms/IPO",
+  ]
+  sources = [
+    "llvm-extract.cpp",
+  ]
+}

llvm/utils/gn/secondary/llvm/tools/llvm-link/BUILD.gn

+executable("llvm-link") {
+  deps = [
+    "//llvm/lib/Bitcode/Reader",
+    "//llvm/lib/Bitcode/Writer",
+    "//llvm/lib/IR",
+    "//llvm/lib/IRReader",
+    "//llvm/lib/Linker",
+    "//llvm/lib/Object",
+    "//llvm/lib/Support",
+    "//llvm/lib/Transforms/IPO",
+    "//llvm/lib/Transforms/Utils",
+  ]
+  sources = [
+    "llvm-link.cpp",
+  ]
+}