[clang] [clang module] Current Working Directory Pruning (PR #124786)

[Steven Wu via cfe-commits]

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@@ -397,9 +397,91 @@ void ModuleDepCollector::applyDiscoveredDependencies(CompilerInvocation &CI) {
   }
 }
 
+static bool isSafeToIgnoreCWD(const CowCompilerInvocation &CI) {
+  // Check if the command line input uses relative paths.
+  // It is not safe to ignore the current working directory if any of the
+  // command line inputs use relative paths.
+#define IF_RELATIVE_RETURN_FALSE(PATH)                                         \
+  do {                                                                         \
+    if (!PATH.empty() && !llvm::sys::path::is_absolute(PATH))                  \
+      return false;                                                            \
+  } while (0)
+
+#define IF_ANY_RELATIVE_RETURN_FALSE(PATHS)                                    \
+  do {                                                                         \
+    if (std::any_of(PATHS.begin(), PATHS.end(), [](const auto &P) {            \
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cachemeifyoucan wrote:

Nit: `llvm::any_of` is easier to use.

https://github.com/llvm/llvm-project/pull/124786