CodeGenerator.cpp:1611 reads:

auto* whileStmt = WhileStmt::Create(ctx, nullptr, condition, outerBody, stmt->getBeginLoc());

Which gives me the build error: error: too few arguments to function call, expected 7, have 5.

I dug through the LLVM source (as well as another tool which manipulates the AST by linking with LLVM :)) and found the change:

/usr/lib/llvm-11/include/clang/AST/Stmt.h:2300:21: note: 'Create' declared here
static WhileStmt *Create(const ASTContext &Ctx, VarDecl *Var, Expr *Cond, Stmt *Body, SourceLocation WL, SourceLocation LParenLoc, SourceLocation RParenLoc);

So it appears that the newer LLVM wants the locations of the left and right parens. (?)

I made a fix adding clang::SourceLocation() for both arguments, as I saw that's what another similar tool does. (in other words, random guess) But it now compiles and works! I'll commit the fix to a fork should you wish to pull it in.