CPU feature logging

Signed-off-by: Benoit Jacob <jacob.benoit.1@gmail.com>

compiler/plugins/target/LLVMCPU/BUILD.bazel

@@ -100,6 +100,21 @@ iree_compiler_cc_library(
     ],
 )
 
+iree_compiler_cc_library(
+    name = "ResolveCPUAndCPUFeatures",
+    srcs = [
+        "ResolveCPUAndCPUFeatures.cpp",
+    ],
+    hdrs = [
+        "ResolveCPUAndCPUFeatures.h",
+    ],
+    deps = [
+        "@llvm-project//llvm:Support",
+        "@llvm-project//llvm:Target",
+        "@llvm-project//llvm:TargetParser",
+    ],
+)
+
 iree_compiler_cc_library(
     name = "LLVMTargetOptions",
     srcs = [
@@ -109,6 +124,7 @@ iree_compiler_cc_library(
         "LLVMTargetOptions.h",
     ],
     deps = [
+        ":ResolveCPUAndCPUFeatures",
         "//compiler/src/iree/compiler/Utils",
         "@llvm-project//llvm:Analysis",
         "@llvm-project//llvm:Core",

compiler/plugins/target/LLVMCPU/CMakeLists.txt

@@ -89,6 +89,20 @@ iree_cc_library(
   PUBLIC
 )
 
+iree_cc_library(
+  NAME
+    ResolveCPUAndCPUFeatures
+  HDRS
+    "ResolveCPUAndCPUFeatures.h"
+  SRCS
+    "ResolveCPUAndCPUFeatures.cpp"
+  DEPS
+    LLVMSupport
+    LLVMTarget
+    LLVMTargetParser
+  PUBLIC
+)
+
 iree_cc_library(
   NAME
     LLVMTargetOptions
@@ -97,6 +111,7 @@ iree_cc_library(
   SRCS
     "LLVMTargetOptions.cpp"
   DEPS
+    ::ResolveCPUAndCPUFeatures
     LLVMAnalysis
     LLVMCore
     LLVMMC

compiler/plugins/target/LLVMCPU/LLVMTargetOptions.cpp

@@ -6,8 +6,7 @@
 
 #include "compiler/plugins/target/LLVMCPU/LLVMTargetOptions.h"
 
-#include <mutex>
-
+#include "compiler/plugins/target/LLVMCPU/ResolveCPUAndCPUFeatures.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
@@ -19,88 +18,11 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/TargetParser/Host.h"
-#include "llvm/TargetParser/RISCVTargetParser.h"
-#include "llvm/TargetParser/SubtargetFeature.h"
 #include "llvm/TargetParser/Triple.h"
-#include "llvm/TargetParser/X86TargetParser.h"
 #include "mlir/IR/Builders.h"
 
 namespace mlir::iree_compiler::IREE::HAL {
 
-namespace {
-
-bool resolveCPUAndCPUFeatures(llvm::StringRef inCpu,
-                              llvm::StringRef inCpuFeatures,
-                              const llvm::Triple &triple, std::string &outCpu,
-                              std::string &outCpuFeatures) {
-  // Resolve "host"
-  if (inCpu == "host" || inCpuFeatures == "host") {
-    // If either Cpu or CpuFeatures is "host", the other must be either also
-    // host or the default value.
-    bool isCpuHostOrDefault =
-        inCpu.empty() || inCpu == "host" || inCpu == "generic";
-    bool isCpuFeaturesHostOrDefault =
-        inCpuFeatures.empty() || inCpuFeatures == "host";
-    if (!(isCpuHostOrDefault && isCpuFeaturesHostOrDefault)) {
-      llvm::errs()
-          << "error: If either cpu or CpuFeatures is `host`, the other must "
-             "be either also `host` or the default value\n";
-      return false;
-    }
-    outCpu = triple.isX86() ? llvm::sys::getHostCPUName().str() : "";
-    llvm::SubtargetFeatures features;
-    for (auto &feature : llvm::sys::getHostCPUFeatures()) {
-      features.AddFeature(feature.first(), feature.second);
-    }
-    outCpuFeatures = features.getString();
-  } else {
-    outCpu = inCpu;
-    outCpuFeatures = inCpuFeatures;
-  }
-
-  // Target-specific CPU feature tweaks that we need unconditionally.
-  if (triple.isAArch64()) {
-    llvm::SubtargetFeatures targetCpuFeatures(outCpuFeatures);
-    // x18 is platform-reserved per the Aarch64 procedure call specification.
-    targetCpuFeatures.AddFeature("reserve-x18", true);
-    outCpuFeatures = targetCpuFeatures.getString();
-  }
-
-  if (outCpu.empty() || inCpu == "host" || inCpu == "generic" ||
-      inCpu.starts_with("generic-")) {
-    return true;
-  }
-  // If CPU is non-host and non-generic then we need to populate the
-  // corresponding features.
-  llvm::SubtargetFeatures targetCpuFeatures(outCpuFeatures);
-  auto addCpuFeatures = [&](const auto &getFeaturesForCPU,
-                            auto &cpuFeatureList) {
-    getFeaturesForCPU(outCpu, cpuFeatureList, false);
-    for (const auto &feature : cpuFeatureList) {
-      targetCpuFeatures.AddFeature(feature);
-    }
-  };
-  if (triple.isX86()) {
-    llvm::SmallVector<llvm::StringRef> cpuFeatureList;
-    addCpuFeatures(llvm::X86::getFeaturesForCPU, cpuFeatureList);
-  } else if (triple.isRISCV64()) {
-    llvm::SmallVector<std::string> cpuFeatureList;
-    addCpuFeatures(llvm::RISCV::getFeaturesForCPU, cpuFeatureList);
-  } else {
-    llvm::errs()
-        << "error: Resolution of target CPU to target CPU features is not "
-           "implemented on "
-           "this target architecture. Pass explicit CPU features "
-           "instead of a CPU "
-           "on this architecture, or implement that.\n";
-    return false;
-  }
-  outCpuFeatures = targetCpuFeatures.getString();
-  return true;
-}
-
-} // namespace
-
 LLVMTarget::LLVMTarget() {
   // LLVM loop optimization options.
   pipelineTuningOptions.LoopInterleaving = DEFAULT_LOOP_INTERLEAVING;
@@ -122,14 +44,14 @@ LLVMTarget::LLVMTarget() {
   llvmTargetOptions.UniqueSectionNames = true;
 }
 
-std::optional<LLVMTarget> LLVMTarget::create(std::string_view triple,
-                                             std::string_view cpu,
-                                             std::string_view cpuFeatures,
-                                             bool requestLinkEmbedded) {
+std::optional<LLVMTarget> LLVMTarget::create(
+    std::string_view triple, std::string_view cpu, std::string_view cpuFeatures,
+    std::string_view loggingUnspecifiedTargetCPU, bool requestLinkEmbedded) {
   LLVMTarget target;
   target.linkEmbedded = requestLinkEmbedded;
-
-  target.triple = triple;
+  target.triple = (triple.empty() || triple == "host")
+                      ? llvm::sys::getProcessTriple()
+                      : triple;
   llvm::Triple targetTriple(target.triple);
   // Special casing if linkEmbedded.
   if (targetTriple.isWasm()) {
@@ -142,10 +64,13 @@ std::optional<LLVMTarget> LLVMTarget::create(std::string_view triple,
     targetTriple.setEnvironment(llvm::Triple::EnvironmentType::EABI);
     targetTriple.setOS(llvm::Triple::OSType::UnknownOS);
     targetTriple.setObjectFormat(llvm::Triple::ObjectFormatType::ELF);
-    target.triple = targetTriple.str();
   }
-  if (!resolveCPUAndCPUFeatures(cpu, cpuFeatures, llvm::Triple(triple),
-                                target.cpu, target.cpuFeatures)) {
+  target.triple = targetTriple.str();
+  target.cpu = cpu;
+  target.cpuFeatures = cpuFeatures;
+  if (!resolveCPUAndCPUFeatures(llvm::Triple(triple), target.cpu,
+                                target.cpuFeatures,
+                                loggingUnspecifiedTargetCPU)) {
     // Something bad happened, and our target might not be what the user expects
     // but we need to continue to avoid breaking existing users. Hopefully
     // resolveCPUAndCPUFeatures logged a helpful error already.
@@ -155,10 +80,10 @@ std::optional<LLVMTarget> LLVMTarget::create(std::string_view triple,
 }
 
 std::optional<LLVMTarget> LLVMTarget::createForHost() {
-  auto target =
-      LLVMTarget::create(llvm::sys::getProcessTriple(), /*cpu=*/"host",
-                         /*cpuFeatures=*/"host",
-                         /*requestLinkEmbedded=*/true);
+  auto target = LLVMTarget::create(
+      llvm::sys::getProcessTriple(), /*cpu=*/"host",
+      /*cpuFeatures=*/"host", /*loggingUnspecifiedTargetCPU=*/"",
+      /*requestLinkEmbedded=*/true);
   if (target)
     target->populateDefaultsFromTargetMachine();
   return target;
@@ -333,9 +258,8 @@ LLVMTarget::loadFromConfigAttr(Location loc, DictionaryAttr config,
                         "accompanied by 'target_triple'";
       return {};
     }
-    std::optional<LLVMTarget> maybeTarget =
-        LLVMTarget::create(*triple, cpu ? *cpu : "generic",
-                           cpuFeatures ? *cpuFeatures : "", linkEmbedded);
+    std::optional<LLVMTarget> maybeTarget = LLVMTarget::create(
+        *triple, cpu.value_or(""), cpuFeatures.value_or(""), "", linkEmbedded);
     if (!maybeTarget) {
       return {};
     }
@@ -588,6 +512,12 @@ void LLVMCPUTargetCLOptions::bindOptions(OptionsBinder &binder) {
       llvm::cl::cat(category),
       llvm::cl::desc("LLVM target machine CPU features; use 'host' for your "
                      "host native CPU."));
+  binder.opt<std::string>(
+      "iree-llvmcpu-logging-unspecified-target-cpu",
+      loggingUnspecifiedTargetCPU, llvm::cl::cat(category),
+      llvm::cl::desc(
+          "Warning behavior on unspecified target CPU. Accepted values: "
+          " (meaning no logging), \"warn\", \"fatal"));
   binder.opt<bool>(
       "iree-llvmcpu-link-embedded", linkEmbedded, llvm::cl::cat(category),
       llvm::cl::desc("Links binaries into a platform-agnostic ELF to be "
@@ -670,8 +600,9 @@ LLVMTargetOptions LLVMCPUTargetCLOptions::getTargetOptions() {
     targetTriple = llvm::sys::getProcessTriple();
   }
 
-  std::optional<LLVMTarget> maybeTarget = LLVMTarget::create(
-      targetTriple, targetCPU, targetCPUFeatures, linkEmbedded);
+  std::optional<LLVMTarget> maybeTarget =
+      LLVMTarget::create(targetTriple, targetCPU, targetCPUFeatures,
+                         loggingUnspecifiedTargetCPU, linkEmbedded);
   if (maybeTarget) {
     targetOptions.target = *maybeTarget;
   } else {

compiler/plugins/target/LLVMCPU/LLVMTargetOptions.h

@@ -66,10 +66,11 @@ struct LLVMTarget {
   void storeToConfigAttrs(MLIRContext *context,
                           SmallVector<NamedAttribute> &config) const;
 
-  static std::optional<LLVMTarget> create(std::string_view triple,
-                                          std::string_view cpu,
-                                          std::string_view cpuFeatures,
-                                          bool requestLinkEmbedded);
+  static std::optional<LLVMTarget>
+  create(std::string_view triple, std::string_view cpu,
+         std::string_view cpuFeatures,
+         std::string_view loggingUnspecifiedTargetCPU,
+         bool requestLinkEmbedded);
 
   static std::optional<LLVMTarget> createForHost();
 
@@ -170,25 +171,26 @@ createTargetMachine(const LLVMTarget &target);
 // Parse into LLVMTargetOptions using getTargetOptions().
 struct LLVMCPUTargetCLOptions {
   // Target invariant flags.
-  std::string systemLinkerPath = "";
-  std::string embeddedLinkerPath = "";
-  std::string wasmLinkerPath = "";
+  std::string systemLinkerPath;
+  std::string embeddedLinkerPath;
+  std::string wasmLinkerPath;
   bool keepLinkerArtifacts = false;
 
   // Default device options.
-  std::string targetTriple = "";
-  std::string targetCPU = "generic";
-  std::string targetCPUFeatures = "";
+  std::string targetTriple;
+  std::string targetCPU;
+  std::string loggingUnspecifiedTargetCPU;
+  std::string targetCPUFeatures;
   bool linkEmbedded = LLVMTarget::DEFAULT_LINK_EMBEDDED;
   bool linkStatic = LLVMTarget::DEFAULT_LINK_STATIC;
-  std::string staticLibraryOutputPath = "";
+  std::string staticLibraryOutputPath;
   bool debugSymbols = LLVMTarget::DEFAULT_DEBUG_SYMBOLS;
   bool llvmLoopInterleaving = LLVMTarget::DEFAULT_LOOP_INTERLEAVING;
   bool llvmLoopVectorization = LLVMTarget::DEFAULT_LOOP_VECTORIZATION;
   bool llvmLoopUnrolling = LLVMTarget::DEFAULT_LOOP_UNROLLING;
   bool llvmSLPVectorization = LLVMTarget::DEFAULT_SLP_VECTORIZATION;
   SanitizerKind sanitizerKind = LLVMTarget::DEFAULT_SANITIZER_KIND;
-  std::string targetABI = "";
+  std::string targetABI;
   llvm::FloatABI::ABIType targetFloatABI = LLVMTarget::DEFAULT_FLOAT_ABI;
   std::string targetDataLayout = LLVMTarget::DEFAULT_DATA_LAYOUT;
   unsigned targetVectorWidthInBytes = LLVMTarget::DEFAULT_VECTOR_WIDTH_IN_BYTES;