07-introduce-pluggable-frontend-observer.patch

Make calls to `performFrontend` use an observer taken from `getFrontendObserver`, which
is provided by a shared library. Substituting the shared library can plug in our
extractor.

diff --git a/cmake/modules/AddSwift.cmake b/cmake/modules/AddSwift.cmake
index 6d93e52f1d5..10225f40fb1 100644
--- a/cmake/modules/AddSwift.cmake
+++ b/cmake/modules/AddSwift.cmake
@@ -715,6 +715,7 @@ function(add_swift_host_tool executable)
 
         # Include the abi stable system stdlib in our rpath.
         list(APPEND RPATH_LIST "/usr/lib/swift")
+        list(APPEND RPATH_LIST "@executable_path/../lib")
 
       elseif(BOOTSTRAPPING_MODE STREQUAL "CROSSCOMPILE-WITH-HOSTLIBS")
 
@@ -798,7 +799,7 @@ function(add_swift_host_tool executable)
       if(BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
         set_target_properties(${executable} PROPERTIES
           BUILD_WITH_INSTALL_RPATH YES
-          INSTALL_RPATH  "${host_lib_dir}")
+          INSTALL_RPATH  "${host_lib_dir};$ORIGIN/../lib")
       else()
         set_target_properties(${executable} PROPERTIES
           BUILD_WITH_INSTALL_RPATH YES
diff --git a/include/swift/DriverTool/FrontendObserver.h b/include/swift/DriverTool/FrontendObserver.h
new file mode 100644
index 00000000000..4ac9b299a13
--- /dev/null
+++ b/include/swift/DriverTool/FrontendObserver.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "llvm/ADT/ArrayRef.h"
+#include "swift/FrontendTool/FrontendTool.h"
+
+namespace swift {
+
+FrontendObserver* getFrontendObserver(llvm::ArrayRef<const char*> argv);
+
+} // namespace swift
diff --git a/lib/DriverTool/CMakeLists.txt b/lib/DriverTool/CMakeLists.txt
index 869c00fece9..b1f49a976d5 100644
--- a/lib/DriverTool/CMakeLists.txt
+++ b/lib/DriverTool/CMakeLists.txt
@@ -14,16 +14,24 @@ set(driver_common_libs
                 swiftSymbolGraphGen
                 LLVMBitstreamReader)
 
+add_swift_host_library(swiftFrontendObserver SHARED
+   swift_frontend_observer.cpp)
+target_link_libraries(swiftFrontendObserver
+        PUBLIC
+        swiftFrontendTool)
+
 add_swift_host_library(swiftDriverTool STATIC
   ${driver_sources_and_options}
 )
 target_link_libraries(swiftDriverTool
                       PUBLIC
-                      ${driver_common_libs})
+                      ${driver_common_libs}
+                      swiftFrontendObserver)
 
 # If building as part of clang, make sure the headers are installed.
 if(NOT SWIFT_BUILT_STANDALONE)
   add_dependencies(swiftDriverTool clang-resource-headers)
 endif()
 
+set_swift_llvm_is_available(swiftFrontendObserver)
 set_swift_llvm_is_available(swiftDriverTool)
diff --git a/lib/DriverTool/driver.cpp b/lib/DriverTool/driver.cpp
index f71e2de9eae..a500e30827f 100644
--- a/lib/DriverTool/driver.cpp
+++ b/lib/DriverTool/driver.cpp
@@ -31,6 +31,7 @@
 #include "swift/Frontend/PrintingDiagnosticConsumer.h"
 #include "swift/FrontendTool/FrontendTool.h"
 #include "swift/DriverTool/DriverTool.h"
+#include "swift/DriverTool/FrontendObserver.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ConvertUTF.h"
@@ -197,7 +198,8 @@ static int run_driver(StringRef ExecName,
     if (FirstArg == "-frontend") {
       return performFrontend(llvm::makeArrayRef(argv.data()+2,
                                                 argv.data()+argv.size()),
-                             argv[0], (void *)(intptr_t)getExecutablePath);
+                             argv[0], (void *)(intptr_t)getExecutablePath,
+                             getFrontendObserver(argv));
     }
     if (FirstArg == "-modulewrap") {
       return modulewrap_main(llvm::makeArrayRef(argv.data()+2,
@@ -211,7 +213,8 @@ static int run_driver(StringRef ExecName,
         && ExecName == "swift-frontend") {
       return performFrontend(llvm::makeArrayRef(argv.data()+1,
                                                 argv.data()+argv.size()),
-                             argv[0], (void *)(intptr_t)getExecutablePath);
+                             argv[0], (void *)(intptr_t)getExecutablePath,
+                             getFrontendObserver(argv));
     }
 
     if (FirstArg == "repl") {
diff --git a/lib/DriverTool/swift_frontend_observer.cpp b/lib/DriverTool/swift_frontend_observer.cpp
new file mode 100644
index 00000000000..e16b2f970cd
--- /dev/null
+++ b/lib/DriverTool/swift_frontend_observer.cpp
@@ -0,0 +1,9 @@
+#include "swift/DriverTool/FrontendObserver.h"
+
+namespace swift {
+
+FrontendObserver* getFrontendObserver(llvm::ArrayRef<const char*>) {
+  return nullptr;
+}
+
+} // namespace swift