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[lldb] Expose discontinuous functions through SBFunction::GetRanges #117532

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merged 3 commits into from
Dec 3, 2024
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[lldb] Expose discontinuous functions through SBFunction::GetRanges #117532

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[lldb] Expose discontinuous functions through SBFunction::GetRanges
labath Nov 12, 2024
a1b5ee5
Merge remote-tracking branch 'origin/main' into range2
labath Dec 3, 2024
691f0e0
doxygenize
labath Dec 3, 2024
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1 change: 1 addition & 0 deletions lldb/include/lldb/API/SBAddressRangeList.h
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Expand Up @@ -45,6 +45,7 @@ class LLDB_API SBAddressRangeList {
private:
friend class SBBlock;
friend class SBProcess;
friend class SBFunction;

lldb_private::AddressRangeListImpl &ref() const;

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2 changes: 2 additions & 0 deletions lldb/include/lldb/API/SBFunction.h
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Expand Up @@ -43,6 +43,8 @@ class LLDB_API SBFunction {

lldb::SBAddress GetStartAddress();

LLDB_DEPRECATED_FIXME("Not compatible with discontinuous functions.",
"GetRanges()")
lldb::SBAddress GetEndAddress();

lldb::SBAddressRangeList GetRanges();
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5 changes: 2 additions & 3 deletions lldb/include/lldb/Core/AddressRangeListImpl.h
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Expand Up @@ -24,9 +24,8 @@ class AddressRangeListImpl {
public:
AddressRangeListImpl();

AddressRangeListImpl(const AddressRangeListImpl &rhs) = default;
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@labath labath Nov 25, 2024

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I've deleted this because of a combination of a default copy constructor and a non-default assignment operator is very unusual (and it makes the move operations unavailable).


AddressRangeListImpl &operator=(const AddressRangeListImpl &rhs);
explicit AddressRangeListImpl(AddressRanges ranges)
: m_ranges(std::move(ranges)) {}

size_t GetSize() const;

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3 changes: 3 additions & 0 deletions lldb/include/lldb/Symbol/Function.h
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Expand Up @@ -444,8 +444,11 @@ class Function : public UserID, public SymbolContextScope {

Function *CalculateSymbolContextFunction() override;

// DEPRECATED: Use GetAddressRanges instead.
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@bulbazord bulbazord Dec 2, 2024

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Can you make this into a Doxygen comment? It will show up in the generated documentation (for those who use it).

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@labath labath Dec 3, 2024

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Sure.

const AddressRange &GetAddressRange() { return m_range; }

const AddressRanges &GetAddressRanges() const { return m_ranges; }

lldb::LanguageType GetLanguage() const;
/// Find the file and line number of the source location of the start of the
/// function. This will use the declaration if present and fall back on the
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17 changes: 8 additions & 9 deletions lldb/source/API/SBFunction.cpp
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Expand Up @@ -10,6 +10,7 @@
#include "lldb/API/SBAddressRange.h"
#include "lldb/API/SBProcess.h"
#include "lldb/API/SBStream.h"
#include "lldb/Core/AddressRangeListImpl.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Core/Module.h"
#include "lldb/Symbol/CompileUnit.h"
Expand Down Expand Up @@ -153,10 +154,11 @@ SBAddress SBFunction::GetEndAddress() {

SBAddress addr;
if (m_opaque_ptr) {
addr_t byte_size = m_opaque_ptr->GetAddressRange().GetByteSize();
if (byte_size > 0) {
addr.SetAddress(m_opaque_ptr->GetAddressRange().GetBaseAddress());
addr->Slide(byte_size);
llvm::ArrayRef<AddressRange> ranges = m_opaque_ptr->GetAddressRanges();
if (!ranges.empty()) {
// Return the end of the first range, use GetRanges to get all ranges.
addr.SetAddress(ranges.front().GetBaseAddress());
addr->Slide(ranges.front().GetByteSize());
}
}
return addr;
Expand All @@ -166,11 +168,8 @@ lldb::SBAddressRangeList SBFunction::GetRanges() {
LLDB_INSTRUMENT_VA(this);

lldb::SBAddressRangeList ranges;
if (m_opaque_ptr) {
lldb::SBAddressRange range;
(*range.m_opaque_up) = m_opaque_ptr->GetAddressRange();
ranges.Append(std::move(range));
}
if (m_opaque_ptr)
ranges.ref() = AddressRangeListImpl(m_opaque_ptr->GetAddressRanges());

return ranges;
}
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8 changes: 0 additions & 8 deletions lldb/source/Core/AddressRangeListImpl.cpp
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Expand Up @@ -13,14 +13,6 @@ using namespace lldb_private;

AddressRangeListImpl::AddressRangeListImpl() : m_ranges() {}

AddressRangeListImpl &
AddressRangeListImpl::operator=(const AddressRangeListImpl &rhs) {
if (this == &rhs)
return *this;
m_ranges = rhs.m_ranges;
return *this;
}

size_t AddressRangeListImpl::GetSize() const { return m_ranges.size(); }

void AddressRangeListImpl::Reserve(size_t capacity) {
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182 changes: 182 additions & 0 deletions lldb/test/Shell/ScriptInterpreter/Python/sb_function_ranges.s
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@@ -0,0 +1,182 @@
# REQUIRES: x86
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@bulbazord bulbazord Dec 2, 2024

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Is there any way we can have an architecture-independent test? If it's a ton of work, I say don't worry about it, most folks are going to build the x86 target probably.

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@labath labath Dec 3, 2024

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The (only?) easy way would be to use a compiler to generate that, but I don't like the tradeoffs that come with that: the -fbasic-block-sections is not supported for all (or even most) targets. Most notably, it only supports ELF targets right now. This means that the test would come with a lot of other REQUIRES clauses -- that the developer might not be able do anything about (enabling the x86 target -- if it isn't already -- is much easier than trying to find a machine with a specific os/arch combination).

Using the compiler to generate the input also reduces our control over it, which means any assertion would have to be fairly loose to avoid the test breaking with compiler changes (we definitely couldn't assert the exact ranges, and even checking their count might too brittle).


# RUN: split-file %s %t
# RUN: llvm-mc -triple x86_64-pc-linux -filetype=obj %t/input.s -o %t/input.o
# RUN: %lldb %t/input.o -o "command script import %t/script.py" -o exit | FileCheck %s

# CHECK: Found 1 function(s).
# CHECK: foo: [input.o[0x0-0x7), input.o[0x7-0xe), input.o[0x14-0x1b), input.o[0x1b-0x1c)]

#--- script.py
import lldb

def __lldb_init_module(debugger, internal_dict):
target = debugger.GetSelectedTarget()
sym_ctxs = target.FindFunctions("foo")
print(f"Found {len(sym_ctxs)} function(s).")
for ctx in sym_ctxs:
fn = ctx.function
print(f"{fn.name}: {fn.GetRanges()}")

#--- input.s
# An example of a function which has been split into two parts. Roughly
# corresponds to this C code.
# int baz();
# int bar() { return 47; }
# int foo(int flag) { return flag ? bar() : baz(); }
# The function bar has been placed "in the middle" of foo.

.text

.type foo,@function
foo:
.cfi_startproc
cmpl $0, %edi
je foo.__part.2
jmp foo.__part.1
.cfi_endproc
.Lfoo_end:
.size foo, .Lfoo_end-foo

foo.__part.1:
.cfi_startproc
callq bar
jmp foo.__part.3
.Lfoo.__part.1_end:
.size foo.__part.1, .Lfoo.__part.1_end-foo.__part.1
.cfi_endproc

bar:
.cfi_startproc
movl $47, %eax
retq
.cfi_endproc
.Lbar_end:
.size bar, .Lbar_end-bar

foo.__part.2:
.cfi_startproc
callq baz
jmp foo.__part.3
.Lfoo.__part.2_end:
.size foo.__part.2, .Lfoo.__part.2_end-foo.__part.2
.cfi_endproc

foo.__part.3:
.cfi_startproc
retq
.Lfoo.__part.3_end:
.size foo.__part.3, .Lfoo.__part.3_end-foo.__part.3
.cfi_endproc


.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 37 # DW_AT_producer
.byte 8 # DW_FORM_string
.byte 19 # DW_AT_language
.byte 5 # DW_FORM_data2
.byte 17 # DW_AT_low_pc
.byte 1 # DW_FORM_addr
.byte 85 # DW_AT_ranges
.byte 35 # DW_FORM_rnglistx
.byte 116 # DW_AT_rnglists_base
.byte 23 # DW_FORM_sec_offset
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 2 # Abbreviation Code
.byte 46 # DW_TAG_subprogram
.byte 0 # DW_CHILDREN_no
.byte 17 # DW_AT_low_pc
.byte 1 # DW_FORM_addr
.byte 18 # DW_AT_high_pc
.byte 1 # DW_FORM_addr
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 3 # Abbreviation Code
.byte 46 # DW_TAG_subprogram
.byte 0 # DW_CHILDREN_no
.byte 85 # DW_AT_ranges
.byte 35 # DW_FORM_rnglistx
.byte 64 # DW_AT_frame_base
.byte 24 # DW_FORM_exprloc
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)

.section .debug_info,"",@progbits
.Lcu_begin0:
.long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
.Ldebug_info_start0:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] DW_TAG_compile_unit
.asciz "Hand-written DWARF" # DW_AT_producer
.short 29 # DW_AT_language
.quad 0 # DW_AT_low_pc
.byte 1 # DW_AT_ranges
.long .Lrnglists_table_base0 # DW_AT_rnglists_base
.byte 2 # Abbrev [2] DW_TAG_subprogram
.quad bar # DW_AT_low_pc
.quad .Lbar_end # DW_AT_high_pc
.asciz "bar" # DW_AT_name
.byte 3 # Abbrev [3] DW_TAG_subprogram
.byte 0 # DW_AT_ranges
.byte 1 # DW_AT_frame_base
.byte 86
.asciz "foo" # DW_AT_name
.byte 0 # End Of Children Mark
.Ldebug_info_end0:

.section .debug_rnglists,"",@progbits
.long .Ldebug_list_header_end0-.Ldebug_list_header_start0 # Length
.Ldebug_list_header_start0:
.short 5 # Version
.byte 8 # Address size
.byte 0 # Segment selector size
.long 2 # Offset entry count
.Lrnglists_table_base0:
.long .Ldebug_ranges0-.Lrnglists_table_base0
.long .Ldebug_ranges1-.Lrnglists_table_base0
.Ldebug_ranges0:
.byte 6 # DW_RLE_start_end
.quad foo
.quad .Lfoo_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.1
.quad .Lfoo.__part.1_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.2
.quad .Lfoo.__part.2_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.3
.quad .Lfoo.__part.3_end
.byte 0 # DW_RLE_end_of_list
.Ldebug_ranges1:
.byte 6 # DW_RLE_start_end
.quad bar
.quad .Lbar_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.1
.quad .Lfoo.__part.1_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.2
.quad .Lfoo.__part.2_end
.byte 6 # DW_RLE_start_end
.quad foo.__part.3
.quad .Lfoo.__part.3_end
.byte 6 # DW_RLE_start_end
.quad foo
.quad .Lfoo_end
.byte 0 # DW_RLE_end_of_list
.Ldebug_list_header_end0:

.section ".note.GNU-stack","",@progbits
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