compnerd created this revision.
compnerd added reviewers: JDevlieghere, xiaobai.
compnerd added a project: LLDB.
Add some very basic support for `DoLoadImage` and `UnloadImage` for Windows.
This was previously not implemented and would result in a failure at runtime
that is hard to detect.
This implementation is extremely limited but serves as a starting point for
proper support for loading a library. Ideally, the user input would be
converted from UTF-8 to UTF-16. This requires additional heap allocations and
conversion logic. Error recovery there requires additional allocations both
from the local heap and the global heap.
This support enables the use of LLDB's Swift REPL on Windows.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D77287
Files:
lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
lldb/source/Plugins/Platform/Windows/PlatformWindows.h
Index: lldb/source/Plugins/Platform/Windows/PlatformWindows.h
===================================================================
--- lldb/source/Plugins/Platform/Windows/PlatformWindows.h
+++ lldb/source/Plugins/Platform/Windows/PlatformWindows.h
@@ -49,6 +49,15 @@
lldb_private::Status DisconnectRemote() override;
+ uint32_t DoLoadImage(lldb_private::Process *process,
+ const lldb_private::FileSpec &remote_file,
+ const std::vector<std::string> *paths,
+ lldb_private::Status &error,
+ lldb_private::FileSpec *loaded_path) override;
+
+ lldb_private::Status UnloadImage(lldb_private::Process *process,
+ uint32_t image_token) override;
+
lldb::ProcessSP DebugProcess(lldb_private::ProcessLaunchInfo &launch_info,
lldb_private::Debugger &debugger,
lldb_private::Target *target,
@@ -73,6 +82,10 @@
private:
DISALLOW_COPY_AND_ASSIGN(PlatformWindows);
+
+ lldb_private::Status EvaluateLoaderExpression(lldb_private::Process *process,
+ const char *expression,
+ lldb::ValueObjectSP &value);
};
} // namespace lldb_private
Index: lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
===================================================================
--- lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
+++ lldb/source/Plugins/Platform/Windows/PlatformWindows.cpp
@@ -16,11 +16,13 @@
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Breakpoint/BreakpointSite.h"
+#include "lldb/Expression/UserExpression.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Host/HostInfo.h"
+#include "lldb/Target/DynamicLoader.h"
#include "lldb/Target/Process.h"
#include "lldb/Utility/Status.h"
@@ -306,6 +308,112 @@
return error;
}
+Status PlatformWindows::EvaluateLoaderExpression(Process *process,
+ const char *expression,
+ ValueObjectSP &value) {
+ // FIXME(compnerd) `-fdeclspec` is not passed to the clang instance?
+ static const char kLoaderDecls[] =
+ R"(
+ // libloaderapi.h
+
+ // WINBASEAPI BOOL WINAPI FreeModule(HMODULE);
+ extern "C" /* __declspec(dllimport) */ BOOL __stdcall FreeModule(void *hLibModule);
+
+ // WINBASEAPI HMODULE WINAPI LoadLibraryA(LPCSTR);
+ extern "C" /* __declspec(dllimport) */ void * __stdcall LoadLibraryA(const char *);
+ )";
+
+ if (DynamicLoader *loader = process->GetDynamicLoader()) {
+ Status result = loader->CanLoadImage();
+ if (result.Fail())
+ return result;
+ }
+
+ ThreadSP thread = process->GetThreadList().GetExpressionExecutionThread();
+ if (!thread)
+ return Status("selected thread is invalid");
+
+ StackFrameSP frame = thread->GetStackFrameAtIndex(0);
+ if (!frame)
+ return Status("frame 0 is invalid");
+
+ ExecutionContext context;
+ frame->CalculateExecutionContext(context);
+
+ EvaluateExpressionOptions options;
+ options.SetUnwindOnError(true);
+ options.SetIgnoreBreakpoints(true);
+ options.SetExecutionPolicy(eExecutionPolicyAlways);
+ options.SetLanguage(eLanguageTypeC_plus_plus);
+ // LoadLibrary{A,W}/FreeLibrary cannot raise exceptions which we can handle.
+ // They may potentially throw SEH exceptions which we do not know how to
+ // handle currently.
+ options.SetTrapExceptions(false);
+ options.SetTimeout(process->GetUtilityExpressionTimeout());
+
+ Status error;
+ ExpressionResults result =
+ UserExpression::Evaluate(context, options, expression, kLoaderDecls,
+ value, error);
+ if (result != eExpressionCompleted)
+ return error;
+
+ if (value->GetError().Fail())
+ return value->GetError();
+
+ return Status();
+}
+
+uint32_t
+PlatformWindows::DoLoadImage(Process *process, const FileSpec &remote_file,
+ const std::vector<std::string> *paths,
+ Status &error, FileSpec *loaded_path) {
+ if (loaded_path)
+ loaded_path->Clear();
+
+ StreamString expression;
+ expression.Printf("LoadLibraryA(\"%s\")", remote_file.GetPath().c_str());
+
+ ValueObjectSP value;
+ Status result = EvaluateLoaderExpression(process, expression.GetData(),
+ value);
+ if (result.Fail())
+ return LLDB_INVALID_IMAGE_TOKEN;
+
+ Scalar scalar;
+ if (value->ResolveValue(scalar)) {
+ lldb::addr_t address = scalar.ULongLong();
+ if (address == 0)
+ return LLDB_INVALID_IMAGE_TOKEN;
+ return process->AddImageToken(address);
+ }
+ return LLDB_INVALID_IMAGE_TOKEN;
+}
+
+Status PlatformWindows::UnloadImage(Process *process, uint32_t image_token) {
+ const addr_t address = process->GetImagePtrFromToken(image_token);
+ if (address == LLDB_INVALID_ADDRESS)
+ return Status("invalid image token");
+
+ StreamString expression;
+ expression.Printf("FreeLibrary((HMODULE)0x%" PRIx64 ")", address);
+
+ ValueObjectSP value;
+ Status result = EvaluateLoaderExpression(process, expression.GetData(),
+ value);
+ if (result.Fail())
+ return result;
+
+ Scalar scalar;
+ if (value->ResolveValue(scalar)) {
+ if (scalar.UInt(1))
+ return Status("expression failed: \"%s\"", expression.GetData());
+ process->ResetImageToken(image_token);
+ }
+
+ return Status();
+}
+
ProcessSP PlatformWindows::DebugProcess(ProcessLaunchInfo &launch_info,
Debugger &debugger, Target *target,
Status &error) {
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