[SPIR-V] Change a way SPIR-V Backend API works with user facing options (#124745)

This PR fixes #124703:
* added a new API call `SPIRVTranslate` that is to replace entirely old
`SPIRVTranslateModule` after existing clients switch into the new
function;
* the new `SPIRVTranslate` doesn't require option parsing, replacing the
`Opts` argument with explicit `CodeGenOptLevel` and `Triple` arguments;
* the old `SPIRVTranslateModule` call is a wrapper for `SPIRVTranslate`,
it doesn't require option parsing either and doesn't hold any logic
inside except for converting string options into `CodeGenOptLevel` and
`Triple` arguments;
* usage of the extensions list is reworked to avoid writes to the global
cl::opt variable `lib/Target/SPIRV/SPIRVSubtarget.cpp::Extensions` --
instead a new class member in SPIRVSubtarget.cpp is implemented that
allows to replace supported extensions after SPIRVSubtarget.cpp is
created;
* both API calls don't require option parsing and don't write to global
cl::opt variables.

Other related/required changes:
* SPIRV::Capability::Shader is marked as an capability of lesser
priority for OpenCL environment (to remediate absence of the
"avoid-spirv-capabilities" command line option in API calls);
* unit tests are updated and extended to cover testing of a newer API
call;
* old API call is marked with TODO to remove it after existing clients
switch into the new function.

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVAPI.cpp

@@ -8,6 +8,7 @@
 
 #include "SPIRVCommandLine.h"
 #include "SPIRVSubtarget.h"
+#include "SPIRVTargetMachine.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -40,25 +41,6 @@ using namespace llvm;
 
 namespace {
 
-// Mimic limited number of command line flags from llc to provide a better
-// user experience when passing options into the translate API call.
-static cl::opt<char> SpirvOptLevel("spirv-O", cl::Hidden, cl::Prefix,
-                                   cl::init('0'));
-static cl::opt<std::string> SpirvTargetTriple("spirv-mtriple", cl::Hidden,
-                                              cl::init(""));
-
-// Utility to accept options in a command line style.
-void parseSPIRVCommandLineOptions(const std::vector<std::string> &Options,
-                                  raw_ostream *Errs) {
-  static constexpr const char *Origin = "SPIRVTranslateModule";
-  if (!Options.empty()) {
-    std::vector<const char *> Argv(1, Origin);
-    for (const auto &Arg : Options)
-      Argv.push_back(Arg.c_str());
-    cl::ParseCommandLineOptions(Argv.size(), Argv.data(), Origin, Errs);
-  }
-}
-
 std::once_flag InitOnceFlag;
 void InitializeSPIRVTarget() {
   std::call_once(InitOnceFlag, []() {
@@ -75,50 +57,26 @@ namespace llvm {
 // The goal of this function is to facilitate integration of SPIRV Backend into
 // tools and libraries by means of exposing an API call that translate LLVM
 // module to SPIR-V and write results into a string as binary SPIR-V output,
-// providing diagnostics on fail and means of configuring translation in a style
-// of command line options.
+// providing diagnostics on fail and means of configuring translation.
 extern "C" LLVM_EXTERNAL_VISIBILITY bool
-SPIRVTranslateModule(Module *M, std::string &SpirvObj, std::string &ErrMsg,
-                     const std::vector<std::string> &AllowExtNames,
-                     const std::vector<std::string> &Opts) {
+SPIRVTranslate(Module *M, std::string &SpirvObj, std::string &ErrMsg,
+               const std::vector<std::string> &AllowExtNames,
+               llvm::CodeGenOptLevel OLevel, Triple TargetTriple) {
   // Fallbacks for option values.
   static const std::string DefaultTriple = "spirv64-unknown-unknown";
   static const std::string DefaultMArch = "";
 
-  // Parse Opts as if it'd be command line arguments.
-  std::string Errors;
-  raw_string_ostream ErrorStream(Errors);
-  parseSPIRVCommandLineOptions(Opts, &ErrorStream);
-  if (!Errors.empty()) {
-    ErrMsg = Errors;
-    return false;
-  }
-
-  llvm::CodeGenOptLevel OLevel;
-  if (auto Level = CodeGenOpt::parseLevel(SpirvOptLevel)) {
-    OLevel = *Level;
-  } else {
-    ErrMsg = "Invalid optimization level!";
-    return false;
-  }
-
-  // Overrides/ammends `-spirv-ext` command line switch (if present) by the
-  // explicit list of allowed SPIR-V extensions.
   std::set<SPIRV::Extension::Extension> AllowedExtIds;
   StringRef UnknownExt =
       SPIRVExtensionsParser::checkExtensions(AllowExtNames, AllowedExtIds);
   if (!UnknownExt.empty()) {
     ErrMsg = "Unknown SPIR-V extension: " + UnknownExt.str();
     return false;
   }
-  SPIRVSubtarget::addExtensionsToClOpt(AllowedExtIds);
 
   // SPIR-V-specific target initialization.
   InitializeSPIRVTarget();
 
-  Triple TargetTriple(SpirvTargetTriple.empty()
-                          ? M->getTargetTriple()
-                          : Triple::normalize(SpirvTargetTriple));
   if (TargetTriple.getTriple().empty()) {
     TargetTriple.setTriple(DefaultTriple);
     M->setTargetTriple(DefaultTriple);
@@ -142,6 +100,11 @@ SPIRVTranslateModule(Module *M, std::string &SpirvObj, std::string &ErrMsg,
     return false;
   }
 
+  // Set available extensions.
+  SPIRVTargetMachine *STM = static_cast<SPIRVTargetMachine *>(Target.get());
+  const_cast<SPIRVSubtarget *>(STM->getSubtargetImpl())
+      ->initAvailableExtensions(AllowedExtIds);
+
   if (M->getCodeModel())
     Target->setCodeModel(*M->getCodeModel());
 
@@ -177,4 +140,30 @@ SPIRVTranslateModule(Module *M, std::string &SpirvObj, std::string &ErrMsg,
   return true;
 }
 
+// TODO: Remove this wrapper after existing clients switch into a newer
+// implementation of SPIRVTranslate().
+extern "C" LLVM_EXTERNAL_VISIBILITY bool
+SPIRVTranslateModule(Module *M, std::string &SpirvObj, std::string &ErrMsg,
+                     const std::vector<std::string> &AllowExtNames,
+                     const std::vector<std::string> &Opts) {
+  // optional: Opts[0] is a string representation of Triple,
+  // take Module triple otherwise
+  Triple TargetTriple(Opts.empty() || Opts[0].empty()
+                          ? M->getTargetTriple()
+                          : Triple::normalize(Opts[0]));
+  // optional: Opts[1] is a string representation of CodeGenOptLevel,
+  // no optimization otherwise
+  llvm::CodeGenOptLevel OLevel = CodeGenOptLevel::None;
+  if (Opts.size() > 1 && !Opts[1].empty()) {
+    if (auto Level = CodeGenOpt::parseLevel(Opts[1][0])) {
+      OLevel = *Level;
+    } else {
+      ErrMsg = "Invalid optimization level!";
+      return false;
+    }
+  }
+  return SPIRVTranslate(M, SpirvObj, ErrMsg, AllowExtNames, OLevel,
+                        TargetTriple);
+}
+
 } // namespace llvm

llvm/lib/Target/SPIRV/SPIRVCommandLine.cpp

@@ -133,6 +133,11 @@ llvm::StringRef SPIRVExtensionsParser::checkExtensions(
     const std::vector<std::string> &ExtNames,
     std::set<SPIRV::Extension::Extension> &AllowedExtensions) {
   for (const auto &Ext : ExtNames) {
+    if (Ext == "all") {
+      for (const auto &[ExtensionName, ExtensionEnum] : SPIRVExtensionMap)
+        AllowedExtensions.insert(ExtensionEnum);
+      break;
+    }
     auto It = SPIRVExtensionMap.find(Ext);
     if (It == SPIRVExtensionMap.end())
       return Ext;

llvm/lib/Target/SPIRV/SPIRVModuleAnalysis.cpp

@@ -73,8 +73,10 @@ static SPIRV::Requirements
 getSymbolicOperandRequirements(SPIRV::OperandCategory::OperandCategory Category,
                                unsigned i, const SPIRVSubtarget &ST,
                                SPIRV::RequirementHandler &Reqs) {
-  static AvoidCapabilitiesSet
-      AvoidCaps; // contains capabilities to avoid if there is another option
+  // A set of capabilities to avoid if there is another option.
+  AvoidCapabilitiesSet AvoidCaps;
+  if (ST.isOpenCLEnv())
+    AvoidCaps.S.insert(SPIRV::Capability::Shader);
 
   VersionTuple ReqMinVer = getSymbolicOperandMinVersion(Category, i);
   VersionTuple ReqMaxVer = getSymbolicOperandMaxVersion(Category, i);

llvm/lib/Target/SPIRV/SPIRVSubtarget.cpp

@@ -84,7 +84,7 @@ SPIRVSubtarget::SPIRVSubtarget(const Triple &TT, const std::string &CPU,
   OpenCLVersion = VersionTuple(2, 2);
 
   // The order of initialization is important.
-  initAvailableExtensions();
+  initAvailableExtensions(Extensions);
   initAvailableExtInstSets();
 
   GR = std::make_unique<SPIRVGlobalRegistry>(PointerSize);
@@ -135,9 +135,12 @@ bool SPIRVSubtarget::canDirectlyComparePointers() const {
   return !SPVTranslatorCompat && isAtLeastVer(SPIRVVersion, VersionTuple(1, 4));
 }
 
-void SPIRVSubtarget::initAvailableExtensions() {
-  AvailableExtensions.clear();
-  AvailableExtensions.insert(Extensions.begin(), Extensions.end());
+void SPIRVSubtarget::accountForAMDShaderTrinaryMinmax() {
+  if (canUseExtension(
+          SPIRV::Extension::SPV_AMD_shader_trinary_minmax_extension)) {
+    AvailableExtInstSets.insert(
+        SPIRV::InstructionSet::SPV_AMD_shader_trinary_minmax);
+  }
 }
 
 // TODO: use command line args for this rather than just defaults.
@@ -150,9 +153,14 @@ void SPIRVSubtarget::initAvailableExtInstSets() {
     AvailableExtInstSets.insert(SPIRV::InstructionSet::OpenCL_std);
 
   // Handle extended instruction sets from extensions.
-  if (canUseExtension(
-          SPIRV::Extension::SPV_AMD_shader_trinary_minmax_extension)) {
-    AvailableExtInstSets.insert(
-        SPIRV::InstructionSet::SPV_AMD_shader_trinary_minmax);
-  }
+  accountForAMDShaderTrinaryMinmax();
+}
+
+// Set available extensions after SPIRVSubtarget is created.
+void SPIRVSubtarget::initAvailableExtensions(
+    const std::set<SPIRV::Extension::Extension> &AllowedExtIds) {
+  AvailableExtensions.clear();
+  AvailableExtensions.insert(AllowedExtIds.begin(), AllowedExtIds.end());
+
+  accountForAMDShaderTrinaryMinmax();
 }

llvm/lib/Target/SPIRV/SPIRVSubtarget.h

@@ -59,8 +59,8 @@ class SPIRVSubtarget : public SPIRVGenSubtargetInfo {
 
   // TODO: Initialise the available extensions, extended instruction sets
   // based on the environment settings.
-  void initAvailableExtensions();
   void initAvailableExtInstSets();
+  void accountForAMDShaderTrinaryMinmax();
 
 public:
   // This constructor initializes the data members to match that
@@ -69,6 +69,9 @@ class SPIRVSubtarget : public SPIRVGenSubtargetInfo {
                  const std::string &FS, const SPIRVTargetMachine &TM);
   SPIRVSubtarget &initSubtargetDependencies(StringRef CPU, StringRef FS);
 
+  void initAvailableExtensions(
+      const std::set<SPIRV::Extension::Extension> &AllowedExtIds);
+
   // Parses features string setting specified subtarget options.
   // The definition of this function is auto generated by tblgen.
   void ParseSubtargetFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS);

llvm/unittests/Target/SPIRV/CMakeLists.txt

@@ -11,6 +11,7 @@ set(LLVM_LINK_COMPONENTS
   SPIRVCodeGen
   SPIRVAnalysis
   Support
+  TargetParser
   )
 
 add_llvm_target_unittest(SPIRVTests