[PATCH] D67127: [clang-scan-deps] add skip excluded conditional preprocessor block preprocessing optimization

[Alex Lorenz via Phabricator via cfe-commits]

arphaman added inline comments.


================
Comment at: clang/include/clang/Frontend/CompilerInstance.h:256
+  /// preprocessor.
+  void setAdditionalPPCallbacks(std::unique_ptr<PPCallbacks> PPC);
+
----------------
Bigcheese wrote:
> This kinda sounds like it can be called multiple times.  Is there any way you can use chained pp callbacks?
Good idea, I implemented support for adding multiple ones with chained callbacks.


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Comment at: clang/tools/clang-scan-deps/ClangScanDeps.cpp:171-177
+llvm::cl::opt<bool> SkipExcludedPPRanges(
+    "skip-excluded-pp-ranges",
+    llvm::cl::desc(
+        "Use the preprocessor optimization that skips excluded conditionals by "
+        "bumping the buffer pointer in the lexer instead of lexing the tokens  "
+        "until reaching the end directive."),
+    llvm::cl::init(true), llvm::cl::cat(DependencyScannerCategory));
----------------
Bigcheese wrote:
> Is there any reason for this to be configurable other than for perf testing?
It's just for perf-testing / verification. No other reason.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D67127/new/

https://reviews.llvm.org/D67127