[lldb] Have disassembler show load addresses when using a core file by labath · Pull Request #115453 · llvm/llvm-project (original) (raw)

@llvm/pr-subscribers-lldb

Author: Pavel Labath (labath)

Changes

We got a bug report that the disassember output was not relocated (i.e. a load address) for a core file (like it is for a live process). It turns out this behavior it depends on whether the instructions were read from an executable file or from process memory (a core file will not typically contain the memory image for segments backed by an executable file).

It's unclear whether this behavior is intentional, or if it was just trying to handle the case where we're dissassembling a module without a process, but I think it's undesirable. What makes it particularly confusing is that the instruction addresses are relocated in this case (unlike the when we don't have a process), so with large files and adresses it gets very hard to see whether the relocation has been applied or not.

This patch removes the data_from_file check so that the instruction is relocated regardless of where it was read from. It will still not get relocated for the raw module use case, as those can't be relocated anywhere as they don't have a load address.

Full diff: https://github.com/llvm/llvm-project/pull/115453.diff

3 Files Affected:

• (modified) lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp (+4-7)
• (modified) lldb/test/Shell/Commands/command-disassemble-process.yaml (+10-10)
• (modified) lldb/test/Shell/Commands/command-disassemble.s (+5-5)

diff --git a/lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp b/lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp index 31edd8d46c444e..08264d837f9c23 100644 --- a/lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp +++ b/lldb/source/Plugins/Disassembler/LLVMC/DisassemblerLLVMC.cpp @@ -583,7 +583,6 @@ class InstructionLLVMC : public lldb_private::Instruction { lldb::addr_t pc = m_address.GetFileAddress(); m_using_file_addr = true;

•    const bool data_from_file = disasm->m_data_from_file;
     bool use_hex_immediates = true;
     Disassembler::HexImmediateStyle hex_style = Disassembler::eHexStyleC;

@@ -593,12 +592,10 @@ class InstructionLLVMC : public lldb_private::Instruction { use_hex_immediates = target->GetUseHexImmediates(); hex_style = target->GetHexImmediateStyle();

•        if (!data_from_file) {

•          const lldb::addr_t load_addr = m_address.GetLoadAddress(target);

•          if (load_addr != LLDB_INVALID_ADDRESS) {

•            pc = load_addr;

•            m_using_file_addr = false;

•          }

•        const lldb::addr_t load_addr = m_address.GetLoadAddress(target);

•        if (load_addr != LLDB_INVALID_ADDRESS) {

•          pc = load_addr;

•          m_using_file_addr = false;
         }
       }
     }

diff --git a/lldb/test/Shell/Commands/command-disassemble-process.yaml b/lldb/test/Shell/Commands/command-disassemble-process.yaml index 75be1a42fb196d..ce1b37bc8aea7a 100644 --- a/lldb/test/Shell/Commands/command-disassemble-process.yaml +++ b/lldb/test/Shell/Commands/command-disassemble-process.yaml @@ -20,7 +20,7 @@

CHECK: (lldb) disassemble

CHECK-NEXT: command-disassemble-process.exe`main:

-# CHECK-NEXT: 0x4002 <+0>: addb %al, (%rcx) +# CHECK-NEXT: 0x4002 <+0>: jmp 0x4004 ; <+2>

CHECK-NEXT: -> 0x4004 <+2>: addb %al, (%rdx)

CHECK-NEXT: 0x4006 <+4>: addb %al, (%rbx)

CHECK-NEXT: 0x4008 <+6>: addb %al, (%rsi)

@@ -32,7 +32,7 @@

CHECK-NEXT: 0x400a: addb %al, (%rdi)

CHECK-NEXT: (lldb) disassemble --frame

CHECK-NEXT: command-disassemble-process.exe`main:

-# CHECK-NEXT: 0x4002 <+0>: addb %al, (%rcx) +# CHECK-NEXT: 0x4002 <+0>: jmp 0x4004 ; <+2>

CHECK-NEXT: -> 0x4004 <+2>: addb %al, (%rdx)

CHECK-NEXT: 0x4006 <+4>: addb %al, (%rbx)

CHECK-NEXT: 0x4008 <+6>: addb %al, (%rsi)

@@ -44,13 +44,13 @@

CHECK-NEXT: 0x400a: addb %al, (%rdi)

CHECK-NEXT: (lldb) disassemble --address 0x4004

CHECK-NEXT: command-disassemble-process.exe`main:

-# CHECK-NEXT: 0x4002 <+0>: addb %al, (%rcx) +# CHECK-NEXT: 0x4002 <+0>: jmp 0x4004 ; <+2>

CHECK-NEXT: -> 0x4004 <+2>: addb %al, (%rdx)

CHECK-NEXT: 0x4006 <+4>: addb %al, (%rbx)

CHECK-NEXT: 0x4008 <+6>: addb %al, (%rsi)

CHECK-NEXT: (lldb) disassemble --count 7

CHECK-NEXT: command-disassemble-process.exe`main:

-# CHECK-NEXT: 0x4002 <+0>: addb %al, (%rcx) +# CHECK-NEXT: 0x4002 <+0>: jmp 0x4004 ; <+2>

CHECK-NEXT: -> 0x4004 <+2>: addb %al, (%rdx)

CHECK-NEXT: 0x4006 <+4>: addb %al, (%rbx)

CHECK-NEXT: 0x4008 <+6>: addb %al, (%rsi)

@@ -81,32 +81,32 @@ Sections:

• Name: .text Type: SHT_PROGBITS Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
• Address: 0x0000000000004000

• Address: 0x0000000000000000 AddressAlign: 0x0000000000001000

• Content: 00000001000200030006000700080009000A000B000E000F00100011001200130016001700180019001A001B001E001F00200021002200230026002700280029002A002B002E002F

• Content: 0000EB00000200030006000700080009000A000B000E000F00100011001200130016001700180019001A001B001E001F00200021002200230026002700280029002A002B002E002F Size: 0x10000

• Name: .note.gnu.build-id Type: SHT_NOTE Flags: [ SHF_ALLOC ]
• Address: 0x0000000000005000

• Address: 0x0000000000001000 AddressAlign: 0x0000000000001000 Content: 040000000800000003000000474E5500DEADBEEFBAADF00D Symbols:

• Name: main Type: STT_FUNC Section: .text
• Value: 0x0000000000004002

• Value: 0x0000000000000002 Size: [[MAIN_SIZE]] ProgramHeaders:

• Type: PT_LOAD Flags: [ PF_X, PF_R ]
• VAddr: 0x4000

• VAddr: 0x0000 Align: 0x1000 FirstSec: .text LastSec: .text

• Type: PT_LOAD Flags: [ PF_W, PF_R ]
• VAddr: 0x5000

• VAddr: 0x1000 Align: 0x1000 FirstSec: .note.gnu.build-id LastSec: .note.gnu.build-id diff --git a/lldb/test/Shell/Commands/command-disassemble.s b/lldb/test/Shell/Commands/command-disassemble.s index 10ce8354025ac5..1625f80468eb17 100644 --- a/lldb/test/Shell/Commands/command-disassemble.s +++ b/lldb/test/Shell/Commands/command-disassemble.s @@ -15,7 +15,7 @@

CHECK-NEXT: error: Cannot disassemble around the current PC without a selected frame: no currently running process.

CHECK-NEXT: (lldb) disassemble --start-address 0x0

CHECK-NEXT: command-disassemble.s.tmp`foo:

-# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: int $0x10 +# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: jmp 0x2 ; <+2>

CHECK-NEXT: command-disassemble.s.tmp[0x2] <+2>: int $0x11

CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12

CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13

@@ -41,7 +41,7 @@

CHECK-NEXT: error: End address before start address.

CHECK-NEXT: (lldb) disassemble --address 0x0

CHECK-NEXT: command-disassemble.s.tmp`foo:

-# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: int $0x10 +# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: jmp 0x2 ; <+2>

CHECK-NEXT: command-disassemble.s.tmp[0x2] <+2>: int $0x11

CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12

CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13

@@ -63,7 +63,7 @@

CHECK: command-disassemble.s.tmp[0x203e] <+8190>: int $0x2a

CHECK-NEXT: (lldb) disassemble --start-address 0x0 --count 7

CHECK-NEXT: command-disassemble.s.tmp`foo:

-# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: int $0x10 +# CHECK-NEXT: command-disassemble.s.tmp[0x0] <+0>: jmp 0x2 ; <+2>

CHECK-NEXT: command-disassemble.s.tmp[0x2] <+2>: int $0x11

CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12

CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13

@@ -101,8 +101,8 @@

     .text

foo:

•    int $0x10

•    int $0x11

•    jmp 1f

+1: int $0x11 int $0x12 int $0x13 int $0x14