Windows LLDB does not mask bytes that have breakpoint on it when reading memory

[xusheng6]

LLDB on Windows seems not masking the bytes which have a breakpoint on it. Reading the memory returns 0xcc instead of its original value. This can be reproduced using the following binary helloworld.exe:

.\lldb.exe C:\Users\xushe\debugger_build\debugger\test\binaries\Windows-x86_64\helloworld.exe
(lldb) target create "C:\\Users\\xushe\\debugger_build\\debugger\\test\\binaries\\Windows-x86_64\\helloworld.exe"
Current executable set to 'C:\Users\xushe\debugger_build\debugger\test\binaries\Windows-x86_64\helloworld.exe' (x86_64).
(lldb) b -s helloworld.exe -a 0x140001338
Breakpoint 1: where = helloworld.exe`helloworld.exe[0x0000000140001338], address = 0x0000000140001338
(lldb) r
Process 47296 launched: 'C:\Users\xushe\debugger_build\debugger\test\binaries\Windows-x86_64\helloworld.exe' (x86_64)
Process 47296 stopped
* thread #1, stop reason = breakpoint 1.1
    frame #0: 0x00007ff739cb1338 helloworld.exe
->  0x7ff739cb1338: int3
    0x7ff739cb1339: subl   $0x28, %esp
    0x7ff739cb133c: callq  0x7ff739cb159c
    0x7ff739cb1341: addq   $0x28, %rsp
(lldb) x 0x7ff739cb1338
0x7ff739cb1338: cc 83 ec 28 e8 5b 02 00 00 48 83 c4 28 e9 72 fe  ...(.[...H..(.r.
0x7ff739cb1348: ff ff cc cc 48 83 ec 28 e8 97 07 00 00 85 c0 74  ....H..(.......t

Related to #60062

[llvmbot]

@llvm/issue-subscribers-lldb