labath created this revision.
labath added reviewers: JDevlieghere, jasonmolenda.
Herald added a project: LLDB.
If we have a binary without symbol information (and without
LC_FUNCTION_STARTS, if on a mac), then we have to resort to using
heuristics to determine the function boundaries. However, these don't
always work, and so we can easily end up thinking we have functions
which are several megabytes in size. Attempting to (accidentally)
disassemble these can take a very long time spam the terminal with
thousands of lines of disassembly.
This patch works around that problem by adding a sanity check to the
disassemble command. If we are about to disassemble a function which is
larger than a certain threshold, we will refuse to disassemble such a
function unless the user explicitly specifies the number of instructions
to disassemble, or start/stop addresses for disassembly.
The threshold is currently fairly aggressive (4000 bytes ~~ 1000
instructions). If needed, we can increase it, or even make it
configurable.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D79789
Files:
lldb/source/Commands/CommandObjectDisassemble.cpp
lldb/source/Commands/CommandObjectDisassemble.h
lldb/source/Commands/Options.td
lldb/test/Shell/Commands/Inputs/command-disassemble.lldbinit
lldb/test/Shell/Commands/command-disassemble-process.yaml
lldb/test/Shell/Commands/command-disassemble.s
Index: lldb/test/Shell/Commands/command-disassemble.s
===================================================================
--- lldb/test/Shell/Commands/command-disassemble.s
+++ lldb/test/Shell/Commands/command-disassemble.s
@@ -51,8 +51,15 @@
# CHECK-NEXT: command-disassemble.s.tmp[0x8] <+8>: int $0x14
# CHECK-NEXT: command-disassemble.s.tmp[0xa] <+10>: int $0x15
# CHECK-NEXT: command-disassemble.s.tmp[0xc] <+12>: int $0x16
-# CHECK-NEXT: (lldb) disassemble --address 0xdead
-# CHECK-NEXT: error: Could not find function bounds for address 0xdead
+# CHECK-NEXT: (lldb) disassemble --address 0xdeadb
+# CHECK-NEXT: error: Could not find function bounds for address 0xdeadb
+# CHECK-NEXT: (lldb) disassemble --address 0x100
+# CHECK-NEXT: error: Not disassembling the function because it is very large [0x0000000000000040-0x0000000000002040). To disassemble, specify an instruction count limit, or start/stop addresses.
+# CHECK-NEXT: (lldb) disassemble --address 0x100 --count 3
+# CHECK-NEXT: command-disassemble.s.tmp`very_long:
+# CHECK-NEXT: command-disassemble.s.tmp[0x40] <+0>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x42] <+2>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x44] <+4>: 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
@@ -64,8 +71,32 @@
# CHECK-NEXT: command-disassemble.s.tmp[0xc] <+12>: int $0x16
# CHECK-NEXT: (lldb) disassemble --start-address 0x0 --end-address 0x20 --count 7
# CHECK-NEXT: error: invalid combination of options for the given command
-# CHECK-NEXT: (lldb) disassemble --address 0x0 --count 7
-# CHECK-NEXT: error: invalid combination of options for the given command
+# CHECK-NEXT: (lldb) disassemble --name case1
+# CHECK-NEXT: command-disassemble.s.tmp`n1::case1:
+# CHECK-NEXT: command-disassemble.s.tmp[0x2040] <+0>: int $0x30
+# CHECK-EMPTY:
+# CHECK-NEXT: command-disassemble.s.tmp`n2::case1:
+# CHECK-NEXT: command-disassemble.s.tmp[0x2042] <+0>: int $0x31
+# CHECK-EMPTY:
+# CHECK-NEXT: (lldb) disassemble --name case2
+# CHECK-NEXT: command-disassemble.s.tmp`n1::case2:
+# CHECK-NEXT: command-disassemble.s.tmp[0x2044] <+0>: int $0x32
+# CHECK-NEXT: warning: Not disassembling a range because it is very large [0x0000000000002046-0x0000000000004046). To disassemble, specify an instruction count limit, or start/stop addresses.
+# CHECK-NEXT: (lldb) disassemble --name case3
+# CHECK-NEXT: error: Not disassembling a range because it is very large [0x0000000000004046-0x0000000000006046). To disassemble, specify an instruction count limit, or start/stop addresses.
+# CHECK-NEXT: Not disassembling a range because it is very large [0x0000000000006046-0x0000000000008046). To disassemble, specify an instruction count limit, or start/stop addresses.
+# CHECK-NEXT: (lldb) disassemble --name case3 --count 3
+# CHECK-NEXT: command-disassemble.s.tmp`n1::case3:
+# CHECK-NEXT: command-disassemble.s.tmp[0x4046] <+0>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x4048] <+2>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x404a] <+4>: int $0x2a
+# CHECK-EMPTY:
+# CHECK-NEXT: command-disassemble.s.tmp`n2::case3:
+# CHECK-NEXT: command-disassemble.s.tmp[0x6046] <+0>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x6048] <+2>: int $0x2a
+# CHECK-NEXT: command-disassemble.s.tmp[0x604a] <+4>: int $0x2a
+# CHECK-EMPTY:
+
.text
foo:
@@ -102,3 +133,32 @@
int $0x2d
int $0x2e
int $0x2f
+
+very_long:
+ .rept 0x1000
+ int $42
+ .endr
+
+_ZN2n15case1Ev:
+ int $0x30
+
+_ZN2n25case1Ev:
+ int $0x31
+
+_ZN2n15case2Ev:
+ int $0x32
+
+_ZN2n25case2Ev:
+ .rept 0x1000
+ int $42
+ .endr
+
+_ZN2n15case3Ev:
+ .rept 0x1000
+ int $42
+ .endr
+
+_ZN2n25case3Ev:
+ .rept 0x1000
+ int $42
+ .endr
Index: lldb/test/Shell/Commands/command-disassemble-process.yaml
===================================================================
--- lldb/test/Shell/Commands/command-disassemble-process.yaml
+++ lldb/test/Shell/Commands/command-disassemble-process.yaml
@@ -1,6 +1,7 @@
# REQUIRES: x86
-# RUN: yaml2obj --docnum=1 %s > %T/command-disassemble-process.exe
+# RUN: yaml2obj --docnum=1 -DMAIN_SIZE=8 %s > %T/command-disassemble-process.exe
+# RUN: yaml2obj --docnum=1 -DMAIN_SIZE=4000 %s > %T/command-disassemble-process.big.exe
# RUN: yaml2obj --docnum=2 %s > %t
# RUN: %lldb -c %t %T/command-disassemble-process.exe \
@@ -8,6 +9,9 @@
# RUN: -s %S/Inputs/command-disassemble-process.lldbinit -o exit 2>&1 \
# RUN: | FileCheck %s
+# RUN: %lldb -c %t %T/command-disassemble-process.big.exe \
+# RUN: -o disassemble -o exit 2>&1 | FileCheck %s --check-prefix=BIG
+
# CHECK: (lldb) disassemble
# CHECK-NEXT: command-disassemble-process.exe`main:
# CHECK-NEXT: 0x4002 <+0>: addb %al, (%rcx)
@@ -59,6 +63,8 @@
# CHECK-NEXT: 0x400e: addb %cl, (%rcx)
# CHECK-NEXT: 0x4010: addb %cl, (%rdx)
+# BIG: error: Not disassembling the current function because it is very large [0x0000000000004002-0x0000000000004fa2). To disassemble, specify an instruction count limit, or start/stop addresses.
+
--- !ELF
FileHeader:
Class: ELFCLASS64
@@ -72,6 +78,7 @@
Address: 0x0000000000004000
AddressAlign: 0x0000000000001000
Content: 00000001000200030006000700080009000A000B000E000F00100011001200130016001700180019001A001B001E001F00200021002200230026002700280029002A002B002E002F
+ Size: 0x10000
- Name: .note.gnu.build-id
Type: SHT_NOTE
Flags: [ SHF_ALLOC ]
@@ -83,7 +90,7 @@
Type: STT_FUNC
Section: .text
Value: 0x0000000000004002
- Size: 0x0000000000000008
+ Size: [[MAIN_SIZE]]
ProgramHeaders:
- Type: PT_LOAD
Flags: [ PF_X, PF_R ]
Index: lldb/test/Shell/Commands/Inputs/command-disassemble.lldbinit
===================================================================
--- lldb/test/Shell/Commands/Inputs/command-disassemble.lldbinit
+++ lldb/test/Shell/Commands/Inputs/command-disassemble.lldbinit
@@ -6,7 +6,12 @@
disassemble --start-address 0x4 --end-address 0x8
disassemble --start-address 0x8 --end-address 0x4
disassemble --address 0x0
-disassemble --address 0xdead
+disassemble --address 0xdeadb
+disassemble --address 0x100
+disassemble --address 0x100 --count 3
disassemble --start-address 0x0 --count 7
disassemble --start-address 0x0 --end-address 0x20 --count 7
-disassemble --address 0x0 --count 7
+disassemble --name case1
+disassemble --name case2
+disassemble --name case3
+disassemble --name case3 --count 3
Index: lldb/source/Commands/Options.td
===================================================================
--- lldb/source/Commands/Options.td
+++ lldb/source/Commands/Options.td
@@ -311,7 +311,7 @@
Desc<"Address at which to start disassembling.">;
def disassemble_options_end_address : Option<"end-address", "e">, Group<1>,
Arg<"AddressOrExpression">, Desc<"Address at which to end disassembling.">;
- def disassemble_options_count : Option<"count", "c">, Groups<[2,3,4,5]>,
+ def disassemble_options_count : Option<"count", "c">, Groups<[2,3,4,5,7]>,
Arg<"NumLines">, Desc<"Number of instructions to display.">;
def disassemble_options_name : Option<"name", "n">, Group<3>,
Arg<"FunctionName">, Completion<"Symbol">,
Index: lldb/source/Commands/CommandObjectDisassemble.h
===================================================================
--- lldb/source/Commands/CommandObjectDisassemble.h
+++ lldb/source/Commands/CommandObjectDisassemble.h
@@ -73,15 +73,19 @@
protected:
bool DoExecute(Args &command, CommandReturnObject &result) override;
- llvm::Expected<std::vector<AddressRange>> GetRangesForSelectedMode();
+ llvm::Expected<std::vector<AddressRange>>
+ GetRangesForSelectedMode(CommandReturnObject &result);
llvm::Expected<std::vector<AddressRange>> GetContainingAddressRanges();
llvm::Expected<std::vector<AddressRange>> GetCurrentFunctionRanges();
llvm::Expected<std::vector<AddressRange>> GetCurrentLineRanges();
- llvm::Expected<std::vector<AddressRange>> GetNameRanges();
+ llvm::Expected<std::vector<AddressRange>>
+ GetNameRanges(CommandReturnObject &result);
llvm::Expected<std::vector<AddressRange>> GetPCRanges();
llvm::Expected<std::vector<AddressRange>> GetStartEndAddressRanges();
+ llvm::Error CheckRangeSize(const AddressRange &range, llvm::StringRef what);
+
CommandOptions m_options;
};
Index: lldb/source/Commands/CommandObjectDisassemble.cpp
===================================================================
--- lldb/source/Commands/CommandObjectDisassemble.cpp
+++ lldb/source/Commands/CommandObjectDisassemble.cpp
@@ -214,6 +214,20 @@
CommandObjectDisassemble::~CommandObjectDisassemble() = default;
+llvm::Error CommandObjectDisassemble::CheckRangeSize(const AddressRange &range,
+ llvm::StringRef what) {
+ if (m_options.num_instructions > 0 || range.GetByteSize() < 4000)
+ return llvm::Error::success();
+ StreamString msg;
+ msg << "Not disassembling " << what << " because it is very large ";
+ range.Dump(&msg, &GetSelectedTarget(), Address::DumpStyleLoadAddress,
+ Address::DumpStyleFileAddress);
+ msg << ". To disassemble, specify an instruction count limit, or start/stop "
+ "addresses.";
+ return llvm::createStringError(llvm::inconvertibleErrorCode(),
+ msg.GetString());
+}
+
llvm::Expected<std::vector<AddressRange>>
CommandObjectDisassemble::GetContainingAddressRanges() {
std::vector<AddressRange> ranges;
@@ -254,6 +268,9 @@
"Could not find function bounds for address 0x%" PRIx64,
m_options.symbol_containing_addr);
}
+
+ if (llvm::Error err = CheckRangeSize(ranges[0], "the function"))
+ return std::move(err);
return ranges;
}
@@ -275,6 +292,8 @@
} else
range = {frame->GetFrameCodeAddress(), DEFAULT_DISASM_BYTE_SIZE};
+ if (llvm::Error err = CheckRangeSize(range, "the current function"))
+ return std::move(err);
return std::vector<AddressRange>{range};
}
@@ -298,7 +317,7 @@
}
llvm::Expected<std::vector<AddressRange>>
-CommandObjectDisassemble::GetNameRanges() {
+CommandObjectDisassemble::GetNameRanges(CommandReturnObject &result) {
ConstString name(m_options.func_name.c_str());
const bool include_symbols = true;
const bool include_inlines = true;
@@ -309,6 +328,7 @@
name, eFunctionNameTypeAuto, include_symbols, include_inlines, sc_list);
std::vector<AddressRange> ranges;
+ llvm::Error range_errs = llvm::Error::success();
AddressRange range;
const uint32_t scope =
eSymbolContextBlock | eSymbolContextFunction | eSymbolContextSymbol;
@@ -317,14 +337,21 @@
for (uint32_t range_idx = 0;
sc.GetAddressRange(scope, range_idx, use_inline_block_range, range);
++range_idx) {
- ranges.push_back(range);
+ if (llvm::Error err = CheckRangeSize(range, "a range"))
+ range_errs = joinErrors(std::move(range_errs), std::move(err));
+ else
+ ranges.push_back(range);
}
}
if (ranges.empty()) {
+ if (range_errs)
+ return std::move(range_errs);
return llvm::createStringError(llvm::inconvertibleErrorCode(),
"Unable to find symbol with name '%s'.\n",
name.GetCString());
}
+ if (range_errs)
+ result.AppendWarning(toString(std::move(range_errs)));
return ranges;
}
@@ -359,7 +386,8 @@
}
llvm::Expected<std::vector<AddressRange>>
-CommandObjectDisassemble::GetRangesForSelectedMode() {
+CommandObjectDisassemble::GetRangesForSelectedMode(
+ CommandReturnObject &result) {
if (m_options.symbol_containing_addr != LLDB_INVALID_ADDRESS)
return CommandObjectDisassemble::GetContainingAddressRanges();
if (m_options.current_function)
@@ -367,7 +395,7 @@
if (m_options.frame_line)
return CommandObjectDisassemble::GetCurrentLineRanges();
if (!m_options.func_name.empty())
- return CommandObjectDisassemble::GetNameRanges();
+ return CommandObjectDisassemble::GetNameRanges(result);
if (m_options.start_addr != LLDB_INVALID_ADDRESS)
return CommandObjectDisassemble::GetStartEndAddressRanges();
return CommandObjectDisassemble::GetPCRanges();
@@ -440,7 +468,8 @@
if (m_options.raw)
options |= Disassembler::eOptionRawOuput;
- llvm::Expected<std::vector<AddressRange>> ranges = GetRangesForSelectedMode();
+ llvm::Expected<std::vector<AddressRange>> ranges =
+ GetRangesForSelectedMode(result);
if (!ranges) {
result.AppendError(toString(ranges.takeError()));
result.SetStatus(eReturnStatusFailed);
@@ -476,7 +505,7 @@
result.SetStatus(eReturnStatusFailed);
}
if (print_sc_header)
- result.AppendMessage("\n");
+ result.GetOutputStream() << "\n";
}
return result.Succeeded();
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