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In a new Range class was introduced to simplify and the Disassembler API and
reduce duplication. It unintentionally broke the `SBFrame::Disassemble`
functionality because it unconditionally converts the number of instructions to
a `Range{Limit::Instructions, num_instructions}`. This is subtly different from
the previous behavior, where now we're passing a Range and assume it's valid in
the callee, the original code would propagate `num_instructions` and the callee
would compare the value and decided between disassembling instructions or bytes.
Unfortunately the existing tests was not particularly strict:
disassembly = frame.Disassemble()
self.assertNotEqual(len(disassembly), 0, "Disassembly was empty.")
This would pass because without this patch we'd disassemble zero instructions,
resulting in an error:
./bin/lldb /tmp/a.out -o 'b main' -o r -o 'script
print(lldb.frame.Disassemble())'
(lldb) target create "/tmp/a.out"
Current executable set to '/tmp/a.out' (x86_64).
(lldb) b main
Breakpoint 1: where = a.out`main + 11 at foo.c:2:3, address =
0x0000000100003fab
(lldb) r
Process 22141 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x0000000100003fab a.out`main at foo.c:2:3
1 int main() {
-> 2 return 10;
3 }
Process 22141 launched: '/tmp/a.out' (x86_64)
(lldb) script print(lldb.frame.Disassemble())
error: error reading data from section __text
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D89925
Files:
lldb/source/Core/Disassembler.cpp
lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
lldb/test/API/commands/disassemble/basic/main.cpp
Index: lldb/test/API/commands/disassemble/basic/main.cpp
===================================================================
--- lldb/test/API/commands/disassemble/basic/main.cpp
+++ lldb/test/API/commands/disassemble/basic/main.cpp
@@ -2,6 +2,7 @@
sum (int a, int b)
{
int result = a + b; // Set a breakpoint here
+ asm("nop");
return result;
}
Index: lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
===================================================================
--- lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
+++ lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
@@ -57,4 +57,6 @@
frame = threads[0].GetFrameAtIndex(0)
disassembly = frame.Disassemble()
- self.assertNotEqual(len(disassembly), 0, "Disassembly was empty.")
+ self.assertNotEqual(disassembly, "")
+ self.assertNotIn("error", disassembly)
+ self.assertIn(": nop", disassembly)
Index: lldb/source/Core/Disassembler.cpp
===================================================================
--- lldb/source/Core/Disassembler.cpp
+++ lldb/source/Core/Disassembler.cpp
@@ -564,10 +564,16 @@
range.SetByteSize(DEFAULT_DISASM_BYTE_SIZE);
}
- return Disassemble(
- debugger, arch, plugin_name, flavor, exe_ctx, range.GetBaseAddress(),
- {Limit::Instructions, num_instructions}, mixed_source_and_assembly,
- num_mixed_context_lines, options, strm);
+ Disassembler::Limit limit = {Limit::Instructions, num_instructions};
+ if (num_instructions == 0) {
+ limit = {Disassembler::Limit::Bytes, range.GetByteSize()};
+ if (limit.value == 0)
+ limit.value = DEFAULT_DISASM_BYTE_SIZE;
+ }
+
+ return Disassemble(debugger, arch, plugin_name, flavor, exe_ctx,
+ range.GetBaseAddress(), limit, mixed_source_and_assembly,
+ num_mixed_context_lines, options, strm);
}
Instruction::Instruction(const Address &address, AddressClass addr_class)
Index: lldb/test/API/commands/disassemble/basic/main.cpp
===================================================================
--- lldb/test/API/commands/disassemble/basic/main.cpp
+++ lldb/test/API/commands/disassemble/basic/main.cpp
@@ -2,6 +2,7 @@
sum (int a, int b)
{
int result = a + b; // Set a breakpoint here
+ asm("nop");
return result;
}
Index: lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
===================================================================
--- lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
+++ lldb/test/API/commands/disassemble/basic/TestFrameDisassemble.py
@@ -57,4 +57,6 @@
frame = threads[0].GetFrameAtIndex(0)
disassembly = frame.Disassemble()
- self.assertNotEqual(len(disassembly), 0, "Disassembly was empty.")
+ self.assertNotEqual(disassembly, "")
+ self.assertNotIn("error", disassembly)
+ self.assertIn(": nop", disassembly)
Index: lldb/source/Core/Disassembler.cpp
===================================================================
--- lldb/source/Core/Disassembler.cpp
+++ lldb/source/Core/Disassembler.cpp
@@ -564,10 +564,16 @@
range.SetByteSize(DEFAULT_DISASM_BYTE_SIZE);
}
- return Disassemble(
- debugger, arch, plugin_name, flavor, exe_ctx, range.GetBaseAddress(),
- {Limit::Instructions, num_instructions}, mixed_source_and_assembly,
- num_mixed_context_lines, options, strm);
+ Disassembler::Limit limit = {Limit::Instructions, num_instructions};
+ if (num_instructions == 0) {
+ limit = {Disassembler::Limit::Bytes, range.GetByteSize()};
+ if (limit.value == 0)
+ limit.value = DEFAULT_DISASM_BYTE_SIZE;
+ }
+
+ return Disassemble(debugger, arch, plugin_name, flavor, exe_ctx,
+ range.GetBaseAddress(), limit, mixed_source_and_assembly,
+ num_mixed_context_lines, options, strm);
}
Instruction::Instruction(const Address &address, AddressClass addr_class)
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