[Runtime] Rename swift_instantiateWitnessTable() -> swift_getWitnessTable()

This runtime function doesn’t always perform instantiation; it’s how we
get a witness table given a conformance, type, and set of instantiation
arguments. Name it accordingly.

Author: DougGregor

include/swift/Runtime/Metadata.h

@@ -385,18 +385,13 @@ SWIFT_RUNTIME_EXPORT SWIFT_CC(swift)
 MetadataResponse swift_checkMetadataState(MetadataRequest request,
                                           const Metadata *type);
 
-/// Instantiate a resilient or generic protocol witness table.
+/// Retrieve a witness table based on a given conformance.
 ///
 /// \param conformance - The protocol conformance descriptor, which
-///   contains the generic witness table record. It may either have fields
-///   that require runtime initialization, or be missing requirements at the
-///   end for which default witnesses are available.
+///   contains any information required to form the witness table.
 ///
 /// \param type - The conforming type, used to form a uniquing key
-///   for the conformance. If the witness table is not dependent on
-///   the substituted type of the conformance, this can be set to
-///   nullptr, in which case there will only be one instantiated
-///   witness table per witness table template.
+///   for the conformance.
 ///
 /// \param instantiationArgs - An opaque pointer that's forwarded to
 ///   the instantiation function, used for conditional conformances.
@@ -406,9 +401,9 @@ MetadataResponse swift_checkMetadataState(MetadataRequest request,
 ///   conformances.
 SWIFT_RUNTIME_EXPORT
 const WitnessTable *
-swift_instantiateWitnessTable(const ProtocolConformanceDescriptor *conformance,
-                              const Metadata *type,
-                              const void * const *instantiationArgs);
+swift_getWitnessTable(const ProtocolConformanceDescriptor *conformance,
+                      const Metadata *type,
+                      const void * const *instantiationArgs);
 
 /// Retrieve an associated type witness from the given witness table.
 ///

include/swift/Runtime/RuntimeFunctions.def

@@ -625,10 +625,10 @@ FUNCTION(CheckMetadataState, swift_checkMetadataState, SwiftCC,
          ATTRS(NoUnwind, ReadOnly))
 
 // const ProtocolWitnessTable *
-// swift_instantiateWitnessTable(const ProtocolConformanceDescriptor *conf,
-//                               const Metadata *type,
-//                               const void * const *instantiationArgs);
-FUNCTION(InstantiateWitnessTable, swift_instantiateWitnessTable, C_CC,
+// swift_getWitnessTable(const ProtocolConformanceDescriptor *conf,
+//                       const Metadata *type,
+//                       const void * const *instantiationArgs);
+FUNCTION(GetWitnessTable, swift_getWitnessTable, C_CC,
          RETURNS(WitnessTablePtrTy),
          ARGS(ProtocolConformanceDescriptorPtrTy,
               TypeMetadataPtrTy,

lib/IRGen/GenProto.cpp

@@ -1074,7 +1074,7 @@ static llvm::Value *emitWitnessTableAccessorCall(
   auto conditionalTables =
       emitConditionalConformancesBuffer(IGF, conformance);
 
-  auto call = IGF.Builder.CreateCall(IGF.IGM.getInstantiateWitnessTableFn(),
+  auto call = IGF.Builder.CreateCall(IGF.IGM.getGetWitnessTableFn(),
                                      {conformanceDescriptor, *srcMetadataCache,
                                       conditionalTables});
 

stdlib/public/runtime/ErrorObject.mm

@@ -250,17 +250,17 @@ static ErrorBridgingInfo getErrorBridgingInfo() {
   assert(conformance &&
          "Foundation overlay not loaded, or 'CFError : Error' conformance "
          "not available");
-  return swift_instantiateWitnessTable(conformance,
-                                       conformance->getCanonicalTypeMetadata(),
-                                       nullptr);
+  return swift_getWitnessTable(conformance,
+                               conformance->getCanonicalTypeMetadata(),
+                               nullptr);
 }
 
 static const HashableWitnessTable *getNSErrorConformanceToHashable() {
   auto conformance = getErrorBridgingInfo().NSObjectHashableConformance;
   assert(conformance &&
          "ObjectiveC overlay not loaded, or 'NSObject : Hashable' conformance "
          "not available");
-  return (const HashableWitnessTable *)swift_instantiateWitnessTable(
+  return (const HashableWitnessTable *)swift_getWitnessTable(
            conformance,
            conformance->getCanonicalTypeMetadata(),
            nullptr);

stdlib/public/runtime/Metadata.cpp

@@ -3962,10 +3962,9 @@ WitnessTableCacheEntry::allocate(
 }
 
 const WitnessTable *
-swift::swift_instantiateWitnessTable(
-                               const ProtocolConformanceDescriptor *conformance,
-                               const Metadata *type,
-                               const void * const *instantiationArgs) {
+swift::swift_getWitnessTable(const ProtocolConformanceDescriptor *conformance,
+                             const Metadata *type,
+                             const void * const *instantiationArgs) {
   /// Local function to unique a foreign witness table, if needed.
   auto uniqueForeignWitnessTableRef =
       [conformance, type](const WitnessTable *candidate)

stdlib/public/runtime/ProtocolConformance.cpp

@@ -167,7 +167,7 @@ ProtocolConformanceDescriptor::getWitnessTable(const Metadata *type) const {
     if (failed) return nullptr;
   }
 
-  return swift_instantiateWitnessTable(this, type, conditionalArgs.data());
+  return swift_getWitnessTable(this, type, conditionalArgs.data());
 }
 
 namespace {

validation-test/stdlib/MicroStdlib/Inputs/RuntimeStubs.c

@@ -14,4 +14,4 @@ void swift_allocateGenericValueMetadata(void) {}
 void swift_initEnumMetadataSinglePayload(void) {}
 void swift_retain(){}
 void swift_allocBox(){}
-void swift_instantiateWitnessTable(void) {}
+void swift_getWitnessTable(void) {}