[clang] [CIR] Cleanup support for C functions (PR #136854)

[Andy Kaylor via cfe-commits]

================
@@ -13,20 +13,76 @@
 
 #include "CIRGenCall.h"
 #include "CIRGenFunction.h"
+#include "CIRGenFunctionInfo.h"
 #include "clang/CIR/MissingFeatures.h"
 
 using namespace clang;
 using namespace clang::CIRGen;
 
-CIRGenFunctionInfo *CIRGenFunctionInfo::create(CanQualType resultType) {
-  void *buffer = operator new(totalSizeToAlloc<ArgInfo>(1));
+CIRGenFunctionInfo *
+CIRGenFunctionInfo::create(CanQualType resultType,
+                           llvm::ArrayRef<CanQualType> argTypes,
+                           RequiredArgs required) {
+  void *buffer = operator new(totalSizeToAlloc<ArgInfo>(argTypes.size() + 1));
 
   CIRGenFunctionInfo *fi = new (buffer) CIRGenFunctionInfo();
+
+  fi->required = required;
+  fi->numArgs = argTypes.size();
   fi->getArgsBuffer()[0].type = resultType;
+  for (unsigned i = 0; i < argTypes.size(); ++i)
+    fi->getArgsBuffer()[i + 1].type = argTypes[i];
 
   return fi;
 }
 
+cir::FuncType CIRGenTypes::getFunctionType(const CIRGenFunctionInfo &fi) {
+  bool inserted = functionsBeingProcessed.insert(&fi).second;
+  assert(inserted && "Recursively being processed?");
+
+  mlir::Type resultType = nullptr;
+  const cir::ABIArgInfo &retAI = fi.getReturnInfo();
+
+  switch (retAI.getKind()) {
+  case cir::ABIArgInfo::Ignore:
+    // TODO(CIR): This should probably be the None type from the builtin
+    // dialect.
+    resultType = nullptr;
+    break;
+
+  case cir::ABIArgInfo::Direct:
+    resultType = retAI.getCoerceToType();
+    break;
+
+  default:
+    assert(false && "NYI");
+  }
+
+  SmallVector<mlir::Type, 8> argTypes;
+  unsigned argNo = 0;
+  CIRGenFunctionInfo::const_arg_iterator it = fi.arg_begin(),
+                                         ie = it + fi.getNumRequiredArgs();
+  for (; it != ie; ++it, ++argNo) {
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andykaylor wrote:

Can you make this a range-based loop?

https://github.com/llvm/llvm-project/pull/136854