[llvm] Strip the full path from __FILE__ in the LDBG macro and keep only the filename (PR #150677)

[Mehdi Amini via llvm-commits]

https://github.com/joker-eph updated https://github.com/llvm/llvm-project/pull/150677

>From 0bb522f35aa9ce1881fba9d57435bd612f336813 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <joker.eph at gmail.com>
Date: Fri, 25 Jul 2025 11:25:55 -0700
Subject: [PATCH 1/2] Strip the full path from __FILE__ in the LDBG macro and
 keep only the filename

---
 llvm/include/llvm/Support/DebugLog.h | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
index 3e53944edc905..da915a31367de 100644
--- a/llvm/include/llvm/Support/DebugLog.h
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -29,7 +29,15 @@ namespace llvm {
 #define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
   for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
        _c = false)                                                             \
-  ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM))
+  ::llvm::impl::LogWithNewline(                                                \
+      TYPE,                                                                    \
+      [] {                                                                     \
+        /* Force constexpr eval */                                             \
+        constexpr const char *filename =                                       \
+            ::llvm::impl::LogWithNewline::getFileName(__FILE__);               \
+        return filename;                                                       \
+      }(),                                                                     \
+      __LINE__, (STREAM))
 
 namespace impl {
 class LogWithNewline {
@@ -51,6 +59,16 @@ class LogWithNewline {
   LogWithNewline(const LogWithNewline &) = delete;
   LogWithNewline &operator=(const LogWithNewline &) = delete;
   LogWithNewline &operator=(LogWithNewline &&) = delete;
+  static constexpr const char *getFileName(const char *path) {
+    // Remove the path prefix from the file name.
+    const char *filename = path;
+    for (const char *p = path; *p != '\0'; ++p) {
+      if (*p == '/' || *p == '\\') {
+        filename = p + 1;
+      }
+    }
+    return filename;
+  }
 
 private:
   raw_ostream &os;

>From e81bdd6f4a9f2267c36481759748b5cbae6e5ee8 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <joker.eph at gmail.com>
Date: Fri, 25 Jul 2025 12:22:39 -0700
Subject: [PATCH 2/2] Use a CMake macro for speedup

---
 llvm/cmake/modules/LLVMProcessSources.cmake |  9 +++++++++
 llvm/include/llvm/Support/DebugLog.h        | 22 +++++++++++----------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/llvm/cmake/modules/LLVMProcessSources.cmake b/llvm/cmake/modules/LLVMProcessSources.cmake
index 0670d60bf2afd..a7f9517ad767c 100644
--- a/llvm/cmake/modules/LLVMProcessSources.cmake
+++ b/llvm/cmake/modules/LLVMProcessSources.cmake
@@ -58,6 +58,15 @@ function(llvm_process_sources OUT_VAR)
   set(sources ${ARG_UNPARSED_ARGUMENTS})
   llvm_check_source_file_list(${sources})
 
+  foreach(fn ${sources})
+    get_filename_component(suf ${fn} EXT)
+    if("${suf}" STREQUAL ".cpp" OR "${suf}" STREQUAL ".c")
+      get_filename_component(short_name ${fn} NAME)
+      set_source_files_properties(${fn} PROPERTIES COMPILE_DEFINITIONS "__SHORT_FILE__=\"${short_name}\"")
+    endif()
+  endforeach()
+
+
   # This adds .td and .h files to the Visual Studio solution:
   add_td_sources(sources)
   find_all_header_files(hdrs "${ARG_ADDITIONAL_HEADER_DIRS}")
diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
index da915a31367de..b1b17e3ede950 100644
--- a/llvm/include/llvm/Support/DebugLog.h
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -26,18 +26,17 @@ namespace llvm {
 //              << "] " << "Bitset contains: " << Bitset << "\n");
 #define LDBG() DEBUGLOG_WITH_STREAM_AND_TYPE(llvm::dbgs(), DEBUG_TYPE)
 
+#if defined(__SHORT_FILE__)
 #define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
   for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
        _c = false)                                                             \
-  ::llvm::impl::LogWithNewline(                                                \
-      TYPE,                                                                    \
-      [] {                                                                     \
-        /* Force constexpr eval */                                             \
-        constexpr const char *filename =                                       \
-            ::llvm::impl::LogWithNewline::getFileName(__FILE__);               \
-        return filename;                                                       \
-      }(),                                                                     \
-      __LINE__, (STREAM))
+  ::llvm::impl::LogWithNewline(TYPE, __SHORT_FILE__, __LINE__, (STREAM))
+#else
+#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE)                            \
+  for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c;  \
+       _c = false)                                                             \
+  ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM))
+#endif
 
 namespace impl {
 class LogWithNewline {
@@ -45,6 +44,9 @@ class LogWithNewline {
   LogWithNewline(const char *debug_type, const char *file, int line,
                  raw_ostream &os)
       : os(os) {
+#if !defined(__SHORT_FILE__)
+    file = ::llvm::impl::LogWithNewline::getShortFileName(file);
+#endif
     if (debug_type)
       os << "[" << debug_type << "] ";
     os << file << ":" << line << " ";
@@ -59,7 +61,7 @@ class LogWithNewline {
   LogWithNewline(const LogWithNewline &) = delete;
   LogWithNewline &operator=(const LogWithNewline &) = delete;
   LogWithNewline &operator=(LogWithNewline &&) = delete;
-  static constexpr const char *getFileName(const char *path) {
+  static constexpr const char *getShortFileName(const char *path) {
     // Remove the path prefix from the file name.
     const char *filename = path;
     for (const char *p = path; *p != '\0'; ++p) {