[Lldb-commits] [lldb] [lldb][windows] add support for out of PATH python.dll resolution (PR #162509)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Charles Zablit (charles-zablit)

<details>
<summary>Changes</summary>

This patch adds the `LLDB_PYTHON_DLL_RELATIVE_PATH` Cmake variable which is the relative path to the directory containing `python.dll`. The path is relative to the directory containing `lldb.exe`.

If this variable is set and the resolved path points to an existing directory, we call `SetDllDirectoryW` to add `python.dll` to the list of DLL search paths.

This, combined with `liblldb.dll` being delay loaded, allows to package `python.dll` with the `llvm` installer.

---
Full diff: https://github.com/llvm/llvm-project/pull/162509.diff


3 Files Affected:

- (modified) lldb/cmake/modules/AddLLDB.cmake (+6) 
- (modified) lldb/tools/driver/CMakeLists.txt (+4) 
- (modified) lldb/tools/driver/Driver.cpp (+49) 


``````````diff
diff --git a/lldb/cmake/modules/AddLLDB.cmake b/lldb/cmake/modules/AddLLDB.cmake
index 28bf8d816d89a..4d2036e68704f 100644
--- a/lldb/cmake/modules/AddLLDB.cmake
+++ b/lldb/cmake/modules/AddLLDB.cmake
@@ -167,6 +167,12 @@ function(add_lldb_executable name)
   )
 
   target_link_libraries(${name} PRIVATE ${ARG_LINK_LIBS})
+  if(WIN32)
+    list(FIND ARG_LINK_LIBS liblldb LIBLLD_INDEX)
+    if(NOT LIBLLD_INDEX EQUAL -1)
+      target_link_options(${name} PRIVATE "/DELAYLOAD:$<TARGET_FILE_BASE_NAME:liblldb>.dll")
+    endif()
+  endif()
   if(CLANG_LINK_CLANG_DYLIB)
     target_link_libraries(${name} PRIVATE clang-cpp)
   else()
diff --git a/lldb/tools/driver/CMakeLists.txt b/lldb/tools/driver/CMakeLists.txt
index 5c0cac484cc94..941ef0d83385b 100644
--- a/lldb/tools/driver/CMakeLists.txt
+++ b/lldb/tools/driver/CMakeLists.txt
@@ -34,6 +34,10 @@ add_dependencies(lldb
   ${tablegen_deps}
 )
 
+if(DEFINED LLDB_PYTHON_DLL_RELATIVE_PATH)
+  target_compile_definitions(lldb PRIVATE LLDB_PYTHON_DLL_RELATIVE_PATH="${LLDB_PYTHON_DLL_RELATIVE_PATH}")
+endif()
+
 if(LLDB_BUILD_FRAMEWORK)
   # In the build-tree, we know the exact path to the framework directory.
   # The installed framework can be in different locations.
diff --git a/lldb/tools/driver/Driver.cpp b/lldb/tools/driver/Driver.cpp
index 16cc736441b59..df31d649ada48 100644
--- a/lldb/tools/driver/Driver.cpp
+++ b/lldb/tools/driver/Driver.cpp
@@ -22,11 +22,15 @@
 #include "lldb/Host/MainLoop.h"
 #include "lldb/Host/MainLoopBase.h"
 #include "lldb/Utility/Status.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/ConvertUTF.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Signals.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include "llvm/Support/WithColor.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -426,6 +430,47 @@ SBError Driver::ProcessArgs(const opt::InputArgList &args, bool &exiting) {
   return error;
 }
 
+#ifdef _WIN32
+// Returns the full path to the lldb.exe executable
+inline std::wstring GetPathToExecutableW() {
+  // Iterate until we reach the Windows max path length (32,767).
+  std::vector<WCHAR> buffer;
+  buffer.resize(MAX_PATH);
+  while (buffer.size() < 32767) {
+    if (GetModuleFileNameW(NULL, buffer.data(), buffer.size()) < buffer.size())
+      return std::wstring(buffer.begin(), buffer.end());
+    buffer.resize(buffer.size() * 2);
+  }
+  return L"";
+}
+
+// Resolve the full path of the directory defined by
+// LLDB_PYTHON_DLL_RELATIVE_PATH. If it exists, add it to the list of DLL search
+// directories.
+void AddPythonDLLToSearchPath() {
+  std::wstring modulePath = GetPathToExecutableW();
+  if (modulePath.empty()) {
+    WithColor::error() << "Unable to find python: " << GetLastError() << '\n';
+    return;
+  }
+
+  SmallVector<char, MAX_PATH> utf8Path;
+  if (sys::windows::UTF16ToUTF8(modulePath.c_str(), modulePath.length(),
+                                utf8Path))
+    return;
+  sys::path::remove_filename(utf8Path);
+  sys::path::append(utf8Path, LLDB_PYTHON_DLL_RELATIVE_PATH);
+  sys::fs::make_absolute(utf8Path);
+
+  SmallVector<wchar_t, 1> widePath;
+  if (sys::windows::widenPath(utf8Path.data(), widePath))
+    return;
+
+  if (sys::fs::exists(utf8Path))
+    SetDllDirectoryW(widePath.data());
+}
+#endif
+
 std::string EscapeString(std::string arg) {
   std::string::size_type pos = 0;
   while ((pos = arg.find_first_of("\"\\", pos)) != std::string::npos) {
@@ -728,6 +773,10 @@ int main(int argc, char const *argv[]) {
                         "~/Library/Logs/DiagnosticReports/.\n");
 #endif
 
+#ifdef _WIN32
+  AddPythonDLLToSearchPath();
+#endif
+
   // Parse arguments.
   LLDBOptTable T;
   unsigned MissingArgIndex;

``````````

</details>


https://github.com/llvm/llvm-project/pull/162509