Revert "RuntimeLibcalls: Generate table of libcall name lengths (#153… (#153864)

…210)"

This reverts commit 9a14b1d.

Revert "RuntimeLibcalls: Return StringRef for libcall names (#153209)"

This reverts commit cb1228f.

Revert "TableGen: Emit statically generated hash table for runtime
libcalls (#150192)"

This reverts commit 769a905.

Reverted three changes because of a CMake error while building llvm-nm
as reported in the following PR:
#150192 (comment)

Author: gulfemsavrun

llvm/benchmarks/CMakeLists.txt

@@ -11,20 +11,3 @@ add_benchmark(FormatVariadicBM FormatVariadicBM.cpp PARTIAL_SOURCES_INTENDED)
 add_benchmark(GetIntrinsicInfoTableEntriesBM GetIntrinsicInfoTableEntriesBM.cpp PARTIAL_SOURCES_INTENDED)
 add_benchmark(SandboxIRBench SandboxIRBench.cpp PARTIAL_SOURCES_INTENDED)
 
-# Extract the list of symbols in a random utility as sample data.
-set(SYMBOL_TEST_DATA_FILE "sample_symbol_list.txt")
-set(SYMBOL_TEST_DATA_SOURCE_BINARY $<TARGET_FILE:llc>)
-
-add_custom_command(OUTPUT ${SYMBOL_TEST_DATA_FILE}
-  COMMAND $<TARGET_FILE:llvm-nm> --no-demangle --no-sort
-  --format=just-symbols
-  ${SYMBOL_TEST_DATA_SOURCE_BINARY} > ${SYMBOL_TEST_DATA_FILE}
-  DEPENDS "$<TARGET_FILE:llvm-nm>" "$<TARGET_FILE:llc>")
-
-add_custom_target(generate-runtime-libcalls-sample-symbol-list
-                  DEPENDS ${SYMBOL_TEST_DATA_FILE})
-add_benchmark(RuntimeLibcallsBench RuntimeLibcalls.cpp PARTIAL_SOURCES_INTENDED)
-
-add_dependencies(RuntimeLibcallsBench generate-runtime-libcalls-sample-symbol-list)
-target_compile_definitions(RuntimeLibcallsBench PRIVATE
-  -DSYMBOL_TEST_DATA_FILE="${CMAKE_CURRENT_BINARY_DIR}/${SYMBOL_TEST_DATA_FILE}")

llvm/benchmarks/RuntimeLibcalls.cpp

@@ -3557,19 +3557,15 @@ class LLVM_ABI TargetLoweringBase {
 
   /// Get the libcall routine name for the specified libcall.
   const char *getLibcallName(RTLIB::Libcall Call) const {
-    // FIXME: Return StringRef
-    return Libcalls.getLibcallName(Call).data();
+    return Libcalls.getLibcallName(Call);
   }
 
   /// Get the libcall routine name for the specified libcall implementation
-  static StringRef getLibcallImplName(RTLIB::LibcallImpl Call) {
-    return RTLIB::RuntimeLibcallsInfo::getLibcallImplName(Call);
+  const char *getLibcallImplName(RTLIB::LibcallImpl Call) const {
+    return Libcalls.getLibcallImplName(Call);
   }
 
-  const char *getMemcpyName() const {
-    // FIXME: Return StringRef
-    return Libcalls.getMemcpyName().data();
-  }
+  const char *getMemcpyName() const { return Libcalls.getMemcpyName(); }
 
   /// Get the comparison predicate that's to be used to test the result of the
   /// comparison libcall against zero. This should only be used with

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -77,17 +77,17 @@ struct RuntimeLibcallsInfo {
 
   /// Get the libcall routine name for the specified libcall.
   // FIXME: This should be removed. Only LibcallImpl should have a name.
-  StringRef getLibcallName(RTLIB::Libcall Call) const {
+  const char *getLibcallName(RTLIB::Libcall Call) const {
     return getLibcallImplName(LibcallImpls[Call]);
   }
 
   /// Get the libcall routine name for the specified libcall implementation.
-  static StringRef getLibcallImplName(RTLIB::LibcallImpl CallImpl) {
+  // FIXME: Change to return StringRef
+  static const char *getLibcallImplName(RTLIB::LibcallImpl CallImpl) {
     if (CallImpl == RTLIB::Unsupported)
-      return StringRef();
-    return StringRef(RuntimeLibcallImplNameTable.getCString(
-                         RuntimeLibcallNameOffsetTable[CallImpl]),
-                     RuntimeLibcallNameSizeTable[CallImpl]);
+      return nullptr;
+    return RuntimeLibcallImplNameTable[RuntimeLibcallNameOffsetTable[CallImpl]]
+        .data();
   }
 
   /// Return the lowering's selection of implementation call for \p Call
@@ -119,10 +119,9 @@ struct RuntimeLibcallsInfo {
 
   /// Return a function name compatible with RTLIB::MEMCPY, or nullptr if fully
   /// unsupported.
-  StringRef getMemcpyName() const {
-    RTLIB::LibcallImpl Memcpy = getLibcallImpl(RTLIB::MEMCPY);
-    if (Memcpy != RTLIB::Unsupported)
-      return getLibcallImplName(Memcpy);
+  const char *getMemcpyName() const {
+    if (const char *Memcpy = getLibcallName(RTLIB::MEMCPY))
+      return Memcpy;
 
     // Fallback to memmove if memcpy isn't available.
     return getLibcallName(RTLIB::MEMMOVE);
@@ -133,41 +132,11 @@ struct RuntimeLibcallsInfo {
     return ImplToLibcall[Impl];
   }
 
-  /// Check if a function name is a recognized runtime call of any kind. This
-  /// does not consider if this call is available for any current compilation,
-  /// just that it is a known call somewhere. This returns the set of all
-  /// LibcallImpls which match the name; multiple implementations with the same
-  /// name may exist but differ in interpretation based on the target context.
-  ///
-  /// Generated by tablegen.
-  LLVM_ABI static inline iota_range<RTLIB::LibcallImpl>
-  lookupLibcallImplName(StringRef Name){
-  // Inlining the early exit on the string name appears to be worthwhile when
-  // querying a real set of symbols
-#define GET_LOOKUP_LIBCALL_IMPL_NAME_BODY
-#include "llvm/IR/RuntimeLibcalls.inc"
-#undef GET_LOOKUP_LIBCALL_IMPL_NAME_BODY
-  }
-
   /// Check if this is valid libcall for the current module, otherwise
   /// RTLIB::Unsupported.
-  LLVM_ABI RTLIB::LibcallImpl
-      getSupportedLibcallImpl(StringRef FuncName) const {
-    for (RTLIB::LibcallImpl Impl : lookupLibcallImplName(FuncName)) {
-      // FIXME: This should not depend on looking up ImplToLibcall, only the
-      // list of libcalls for the module.
-      RTLIB::LibcallImpl Recognized = LibcallImpls[ImplToLibcall[Impl]];
-      if (Recognized != RTLIB::Unsupported)
-        return Recognized;
-    }
-
-    return RTLIB::Unsupported;
-  }
+  LLVM_ABI RTLIB::LibcallImpl getSupportedLibcallImpl(StringRef FuncName) const;
 
 private:
-  LLVM_ABI static iota_range<RTLIB::LibcallImpl>
-  lookupLibcallImplNameImpl(StringRef Name);
-
   /// Stores the implementation choice for each each libcall.
   RTLIB::LibcallImpl LibcallImpls[RTLIB::UNKNOWN_LIBCALL + 1] = {
       RTLIB::Unsupported};
@@ -184,16 +153,17 @@ struct RuntimeLibcallsInfo {
   LLVM_ABI static const char RuntimeLibcallImplNameTableStorage[];
   LLVM_ABI static const StringTable RuntimeLibcallImplNameTable;
   LLVM_ABI static const uint16_t RuntimeLibcallNameOffsetTable[];
-  LLVM_ABI static const uint8_t RuntimeLibcallNameSizeTable[];
 
   /// Map from a concrete LibcallImpl implementation to its RTLIB::Libcall kind.
   LLVM_ABI static const RTLIB::Libcall ImplToLibcall[RTLIB::NumLibcallImpls];
 
-  /// Utility function for tablegenerated lookup function. Return a range of
-  /// enum values that apply for the function name at \p NameOffsetEntry with
-  /// the value \p StrOffset.
-  static inline iota_range<RTLIB::LibcallImpl>
-  libcallImplNameHit(uint16_t NameOffsetEntry, uint16_t StrOffset);
+  /// Check if a function name is a recognized runtime call of any kind. This
+  /// does not consider if this call is available for any current compilation,
+  /// just that it is a known call somewhere. This returns the set of all
+  /// LibcallImpls which match the name; multiple implementations with the same
+  /// name may exist but differ in interpretation based on the target context.
+  LLVM_ABI static iterator_range<ArrayRef<uint16_t>::const_iterator>
+  getRecognizedLibcallImpls(StringRef FuncName);
 
   static bool darwinHasSinCosStret(const Triple &TT) {
     if (!TT.isOSDarwin())

llvm/include/llvm/IR/RuntimeLibcalls.h

@@ -145,7 +145,7 @@ static bool lowerObjCCall(Function &F, RTLIB::LibcallImpl NewFn,
 
   // FIXME: When RuntimeLibcalls is an analysis, check if the function is really
   // supported, and go through RTLIB::Libcall.
-  StringRef NewFnName = RTLIB::RuntimeLibcallsInfo::getLibcallImplName(NewFn);
+  const char *NewFnName = RTLIB::RuntimeLibcallsInfo::getLibcallImplName(NewFn);
 
   // If we haven't already looked up this function, check to see if the
   // program already contains a function with this name.

llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp

@@ -9,7 +9,6 @@
 #include "llvm/IR/RuntimeLibcalls.h"
 #include "llvm/ADT/StringTable.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/xxhash.h"
 #include "llvm/TargetParser/ARMTargetParser.h"
 
 #define DEBUG_TYPE "runtime-libcalls-info"
@@ -19,11 +18,9 @@ using namespace RTLIB;
 
 #define GET_INIT_RUNTIME_LIBCALL_NAMES
 #define GET_SET_TARGET_RUNTIME_LIBCALL_SETS
-#define DEFINE_GET_LOOKUP_LIBCALL_IMPL_NAME
 #include "llvm/IR/RuntimeLibcalls.inc"
 #undef GET_INIT_RUNTIME_LIBCALL_NAMES
 #undef GET_SET_TARGET_RUNTIME_LIBCALL_SETS
-#undef DEFINE_GET_LOOKUP_LIBCALL_IMPL_NAME
 
 /// Set default libcall names. If a target wants to opt-out of a libcall it
 /// should be placed here.
@@ -61,23 +58,49 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
   }
 }
 
-LLVM_ATTRIBUTE_ALWAYS_INLINE
-iota_range<RTLIB::LibcallImpl>
-RuntimeLibcallsInfo::libcallImplNameHit(uint16_t NameOffsetEntry,
-                                        uint16_t StrOffset) {
-  int NumAliases = 1;
-  for (uint16_t Entry : ArrayRef(RuntimeLibcallNameOffsetTable)
-                            .drop_front(NameOffsetEntry + 1)) {
-    if (Entry != StrOffset)
-      break;
-    ++NumAliases;
+RTLIB::LibcallImpl
+RuntimeLibcallsInfo::getSupportedLibcallImpl(StringRef FuncName) const {
+  const ArrayRef<uint16_t> RuntimeLibcallNameOffsets(
+      RuntimeLibcallNameOffsetTable);
+
+  iterator_range<ArrayRef<uint16_t>::const_iterator> Range =
+      getRecognizedLibcallImpls(FuncName);
+
+  for (auto I = Range.begin(); I != Range.end(); ++I) {
+    RTLIB::LibcallImpl Impl =
+        static_cast<RTLIB::LibcallImpl>(I - RuntimeLibcallNameOffsets.begin());
+
+    // FIXME: This should not depend on looking up ImplToLibcall, only the list
+    // of libcalls for the module.
+    RTLIB::LibcallImpl Recognized = LibcallImpls[ImplToLibcall[Impl]];
+    if (Recognized != RTLIB::Unsupported)
+      return Recognized;
   }
 
-  RTLIB::LibcallImpl ImplStart = static_cast<RTLIB::LibcallImpl>(
-      &RuntimeLibcallNameOffsetTable[NameOffsetEntry] -
-      &RuntimeLibcallNameOffsetTable[0]);
-  return enum_seq(ImplStart,
-                  static_cast<RTLIB::LibcallImpl>(ImplStart + NumAliases));
+  return RTLIB::Unsupported;
+}
+
+iterator_range<ArrayRef<uint16_t>::const_iterator>
+RuntimeLibcallsInfo::getRecognizedLibcallImpls(StringRef FuncName) {
+  StringTable::Iterator It = lower_bound(RuntimeLibcallImplNameTable, FuncName);
+  if (It == RuntimeLibcallImplNameTable.end() || *It != FuncName)
+    return iterator_range(ArrayRef<uint16_t>());
+
+  uint16_t IndexVal = It.offset().value();
+  const ArrayRef<uint16_t> TableRef(RuntimeLibcallNameOffsetTable);
+
+  ArrayRef<uint16_t>::const_iterator E = TableRef.end();
+  ArrayRef<uint16_t>::const_iterator EntriesBegin =
+      std::lower_bound(TableRef.begin(), E, IndexVal);
+  ArrayRef<uint16_t>::const_iterator EntriesEnd = EntriesBegin;
+
+  while (EntriesEnd != E && *EntriesEnd == IndexVal)
+    ++EntriesEnd;
+
+  assert(EntriesBegin != E &&
+         "libcall found in name table but not offset table");
+
+  return make_range(EntriesBegin, EntriesEnd);
 }
 
 bool RuntimeLibcallsInfo::isAAPCS_ABI(const Triple &TT, StringRef ABIName) {

llvm/lib/IR/RuntimeLibcalls.cpp

@@ -1422,7 +1422,7 @@ SmallVector<const char *> LTO::getRuntimeLibcallSymbols(const Triple &TT) {
 
   for (RTLIB::LibcallImpl Impl : LibcallImpls) {
     if (Impl != RTLIB::Unsupported)
-      LibcallSymbols.push_back(Libcalls.getLibcallImplName(Impl).data());
+      LibcallSymbols.push_back(Libcalls.getLibcallImplName(Impl));
   }
 
   return LibcallSymbols;