[clang-tools-extra] [clang-tidy] Add llvm-use-vector-utils (PR #177722)

[Baranov Victor via cfe-commits]

================
@@ -0,0 +1,126 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseVectorUtilsCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::llvm_check {
+
+UseVectorUtilsCheck::UseVectorUtilsCheck(StringRef Name,
+                                         ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
+                                        utils::IncludeSorter::IS_LLVM),
+               areDiagsSelfContained()) {}
+
+void UseVectorUtilsCheck::registerPPCallbacks(const SourceManager &SM,
+                                              Preprocessor *PP,
+                                              Preprocessor *ModuleExpanderPP) {
+  Inserter.registerPreprocessor(PP);
+}
+
+void UseVectorUtilsCheck::registerMatchers(MatchFinder *Finder) {
+  // Match `llvm::to_vector(llvm::map_range(X, F))`.
+  Finder->addMatcher(
+      callExpr(callee(functionDecl(hasName("::llvm::to_vector"))),
+               hasArgument(0, callExpr(callee(functionDecl(
+                                           hasName("::llvm::map_range"))))
+                                  .bind("inner_call")))
+          .bind("map_range_call"),
+      this);
+
+  // Match `llvm::to_vector(llvm::make_filter_range(X, Pred))`.
+  Finder->addMatcher(
+      callExpr(callee(functionDecl(hasName("::llvm::to_vector"))),
+               hasArgument(0, callExpr(callee(functionDecl(hasName(
+                                           "::llvm::make_filter_range"))))
+                                  .bind("inner_call")))
+          .bind("filter_range_call"),
+      this);
+}
+
+void UseVectorUtilsCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *MapRangeCall = Result.Nodes.getNodeAs<CallExpr>("map_range_call");
+  const auto *FilterRangeCall =
+      Result.Nodes.getNodeAs<CallExpr>("filter_range_call");
+  if (!MapRangeCall && !FilterRangeCall)
+    return;
+
+  const auto *InnerCall = Result.Nodes.getNodeAs<CallExpr>("inner_call");
+  assert(InnerCall && "inner_call must be bound if map_range_call or "
+                      "filter_range_call matched");
+  // Only handle the 2-argument overloads of `map_range`/`make_filter_range`, to
+  // future-proof against additional overloads.
+  if (InnerCall->getNumArgs() != 2)
+    return;
+
+  const CallExpr *OuterCall = MapRangeCall ? MapRangeCall : FilterRangeCall;
+
+  const SourceManager &SM = *Result.SourceManager;
+  const LangOptions &LangOpts = getLangOpts();
+
+  // Determine the base replacement function name.
+  const StringRef ReplacementFuncBase =
+      MapRangeCall ? "llvm::map_to_vector" : "llvm::filter_to_vector";
+  const StringRef InnerFuncName =
+      MapRangeCall ? "llvm::map_range" : "llvm::make_filter_range";
+
+  // Check if `to_vector` was called with an explicit size template argument.
+  std::string SizeTemplateArg;
+  if (const auto *DRE =
+          dyn_cast<DeclRefExpr>(OuterCall->getCallee()->IgnoreImplicit())) {
+    if (DRE->hasExplicitTemplateArgs()) {
+      // Extract the template argument text (e.g., `<4>`).
+      const auto TemplateArgsCharRange = CharSourceRange::getTokenRange(
+          DRE->getLAngleLoc(), DRE->getRAngleLoc());
+      SizeTemplateArg =
+          Lexer::getSourceText(TemplateArgsCharRange, SM, LangOpts).str();
+    }
+  }
+
+  const std::string ReplacementFunc =
----------------
vbvictor wrote:

I think the replacement logic it too complex and can be made easier:
Lets say we want to rewrite
```
llvm::to_vector<4>(llvm::map_range(vec, transform)) -> llvm::map_to_vector<4>(vec, transform)
```
We already binded `to_vector` to `outer_call` and `llvm::map_range` to `inner_call`, then all we need to do is:

1) remove range `llvm::map_range(` from `inner_call` plus `rparen` (can be extracted via `getRParenLoc()`)
2) rename range of function name from `outer_call` from `to_vector` to `map_to_vector` (without touching any template arguments)

These steps should be easy `CreateReplacement`/`CreateRemoval`, so no need to manually reconstruct whole expression and care about preserving `<4>` arguments

https://github.com/llvm/llvm-project/pull/177722