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//===- JITLoaderGDB.h - Register objects via GDB JIT interface -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/Orc/TargetProcess/JITLoaderGDB.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/Support/BinaryStreamReader.h"
#include "llvm/Support/ManagedStatic.h"
#include <cstdint>
#include <mutex>
#include <utility>
#define DEBUG_TYPE "orc"
// First version as landed in August 2009
static constexpr uint32_t JitDescriptorVersion = 1;
// Keep in sync with gdb/gdb/jit.h
extern "C" {
typedef enum {
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} jit_actions_t;
struct jit_code_entry {
struct jit_code_entry *next_entry;
struct jit_code_entry *prev_entry;
const char *symfile_addr;
uint64_t symfile_size;
};
struct jit_descriptor {
uint32_t version;
// This should be jit_actions_t, but we want to be specific about the
// bit-width.
uint32_t action_flag;
struct jit_code_entry *relevant_entry;
struct jit_code_entry *first_entry;
};
// We put information about the JITed function in this global, which the
// debugger reads. Make sure to specify the version statically, because the
// debugger checks the version before we can set it during runtime.
struct jit_descriptor __jit_debug_descriptor = {JitDescriptorVersion, 0,
nullptr, nullptr};
// Debuggers that implement the GDB JIT interface put a special breakpoint in
// this function.
LLVM_ATTRIBUTE_NOINLINE void __jit_debug_register_code() {
// The noinline and the asm prevent calls to this function from being
// optimized out.
#if !defined(_MSC_VER)
asm volatile("" ::: "memory");
#endif
}
}
using namespace llvm;
// Serialize rendezvous with the debugger as well as access to shared data.
ManagedStatic<std::mutex> JITDebugLock;
static std::pair<const char *, uint64_t> readDebugObjectInfo(uint8_t *ArgData,
uint64_t ArgSize) {
BinaryStreamReader ArgReader(ArrayRef<uint8_t>(ArgData, ArgSize),
support::endianness::big);
uint64_t Addr, Size;
cantFail(ArgReader.readInteger(Addr));
cantFail(ArgReader.readInteger(Size));
return std::make_pair(jitTargetAddressToPointer<const char *>(Addr), Size);
}
extern "C" orc::tpctypes::CWrapperFunctionResult
llvm_orc_registerJITLoaderGDBWrapper(uint8_t *Data, uint64_t Size) {
if (Size != sizeof(uint64_t) + sizeof(uint64_t))
return orc::tpctypes::WrapperFunctionResult::from(
"Invalid arguments to llvm_orc_registerJITLoaderGDBWrapper")
.release();
jit_code_entry *E = new jit_code_entry;
std::tie(E->symfile_addr, E->symfile_size) = readDebugObjectInfo(Data, Size);
E->prev_entry = nullptr;
std::lock_guard<std::mutex> Lock(*JITDebugLock);
// Insert this entry at the head of the list.
jit_code_entry *NextEntry = __jit_debug_descriptor.first_entry;
E->next_entry = NextEntry;
if (NextEntry) {
NextEntry->prev_entry = E;
}
__jit_debug_descriptor.first_entry = E;
__jit_debug_descriptor.relevant_entry = E;
// Run into the rendezvous breakpoint.
__jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
__jit_debug_register_code();
return orc::tpctypes::WrapperFunctionResult().release();
}
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