================ @@ -0,0 +1,58 @@ +//===--- DirectToIndirectFCR.h - RISC-V specific pass ---------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +#pragma once + +#include "lldb/lldb-types.h" + +#include "llvm/IR/Instructions.h" +#include "llvm/Pass.h" + +namespace lldb_private { + +class ExecutionContext; + +// During the lldb expression execution lldb wraps a user expression, jittes +// fabricated code and then puts it into the stack memory. Thus, if user tried ---------------- dlav-sc wrote:
Well, lldb generates its own code that wraps expression, something like:
```
#line 1 "<lldb wrapper prefix>"
#ifndef offsetof
#define offsetof(t, d) __builtin_offsetof(t, d)
#endif
#ifndef NULL
#define NULL (__null)
#endif
#ifndef Nil
#define Nil (__null)
#endif
#ifndef nil
#define nil (__null)
#endif
#ifndef YES
#define YES ((BOOL)1)
#endif
#ifndef NO
#define NO ((BOOL)0)
#endif
typedef __INT8_TYPE__ int8_t;
typedef __UINT8_TYPE__ uint8_t;
typedef __INT16_TYPE__ int16_t;
typedef __UINT16_TYPE__ uint16_t;
typedef __INT32_TYPE__ int32_t;
typedef __UINT32_TYPE__ uint32_t;
typedef __INT64_TYPE__ int64_t;
typedef __UINT64_TYPE__ uint64_t;
typedef __INTPTR_TYPE__ intptr_t;
typedef __UINTPTR_TYPE__ uintptr_t;
typedef __SIZE_TYPE__ size_t;
typedef __PTRDIFF_TYPE__ ptrdiff_t;
typedef unsigned short unichar;
extern "C"
{
int printf(const char * __restrict, ...);
}
typedef signed char BOOL;
void
$__lldb_expr(void *$__lldb_arg)
{
;
#line 1 "<user expression 0>"
foo()
;
#line 1 "<lldb wrapper suffix>"
}
```
So lldb have to puts this code somewhere, resolves relocations and executes. I
have no idea where lldb can place the code except of the stack.
I've checked that on x86 lldb does the same:
```
lldb IRMemoryMap::Malloc (79, 0x10, 0x6,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc7040
lldb IRMemoryMap::Malloc (1, 0x1, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc8450
lldb IRMemoryMap::Malloc (102, 0x1, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc8460
lldb IRMemoryMap::Malloc (7, 0x4, 0x6,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc7090
lldb IRMemoryMap::Malloc (31, 0x8, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc84d0
lldb IRMemoryMap::Malloc (111, 0x1, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc84f0
lldb IRMemoryMap::Malloc (1, 0x1, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc8560
lldb IRMemoryMap::Malloc (103, 0x8, 0x2,
eAllocationPolicyProcessOnly) -> 0x7ffff7fc8570
```
```
lldb Function disassembly:
0x7ffff7fc7040: 55 other pushq %rbp
0x7ffff7fc7041: 48 89 e5 other movq %rsp, %rbp
0x7ffff7fc7044: 53 other pushq %rbx
0x7ffff7fc7045: 50 other pushq %rax
0x7ffff7fc7046: 48 89 fb other movq %rdi, %rbx
0x7ffff7fc7049: 48 8d 7d f0 other leaq -0x10(%rbp),
%rdi
0x7ffff7fc704d: 48 b9 00 70 fc f7 ff 7f 00 00 other movabsq
$0x7ffff7fc7000, %rcx ; imm = 0x7FFFF7FC7000
0x7ffff7fc7057: b0 00 other movb $0x0, %al
0x7ffff7fc7059: ff d1 call callq *%rcx
0x7ffff7fc705b: 48 89 5d f0 other movq %rbx,
-0x10(%rbp)
0x7ffff7fc705f: 48 b8 29 51 55 55 55 55 00 00 other movabsq
$0x555555555129, %rax ; imm = 0x555555555129
0x7ffff7fc7069: ff d0 call callq *%rax
0x7ffff7fc706b: 48 83 c4 08 other addq $0x8, %rsp
0x7ffff7fc706f: 5b other popq %rbx
0x7ffff7fc7070: 5d other popq %rbp
0x7ffff7fc7071: c3 return retq
```
https://github.com/llvm/llvm-project/pull/99336
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