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clang-p2996/lldb/test/Shell/Commands/command-disassemble.s
Pavel Labath 8b845ac5ed Recommit "[lldb] Don't dissasemble large functions by default" 
This recommits f665e80c02 which was reverted in 1cbd1b8f69 for breaking
TestFoundationDisassembly.py. The fix is to use --force in the test to avoid
bailing out on large functions.

I have also doubled the large function limit to 8000 bytes (~~ 2000 insns), as
the foundation library contains a lot of large-ish functions. The intent of this
feature is to prevent accidental disassembling of enormous (multi-megabyte)
"functions", not to get in people's way.

The original commit message follows:

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, uses start/stop addresses for disassembly, or passes the
(new) --force argument.

The threshold is currently fairly aggressive (4000 bytes ~~ 1000
instructions). If needed, we can increase it, or even make it
configurable.

Differential Revision: https://reviews.llvm.org/D79789
2020-05-15 11:57:48 +02:00

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# REQUIRES: x86
# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux %s -o %t
# RUN: %lldb %t -o "settings set interpreter.stop-command-source-on-error false" \
# RUN: -s %S/Inputs/command-disassemble.lldbinit -o exit 2>&1 | FileCheck %s
# CHECK: (lldb) disassemble
# CHECK-NEXT: error: Cannot disassemble around the current function without a selected frame.
# CHECK-EMPTY:
# CHECK-NEXT: (lldb) disassemble --line
# CHECK-NEXT: error: Cannot disassemble around the current line without a selected frame.
# CHECK-EMPTY:
# CHECK-NEXT: (lldb) disassemble --frame
# CHECK-NEXT: error: Cannot disassemble around the current function without a selected frame.
# CHECK-EMPTY:
# CHECK-NEXT: (lldb) disassemble --pc
# CHECK-NEXT: error: Cannot disassemble around the current PC without a selected frame.
# CHECK-EMPTY:
# 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[0x2] <+2>: int $0x11
# CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12
# CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13
# 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-EMPTY:
# CHECK-NEXT: command-disassemble.s.tmp`bar:
# CHECK-NEXT: command-disassemble.s.tmp[0xe] <+0>: int $0x17
# CHECK-NEXT: command-disassemble.s.tmp[0x10] <+2>: int $0x18
# CHECK-NEXT: command-disassemble.s.tmp[0x12] <+4>: int $0x19
# CHECK-NEXT: command-disassemble.s.tmp[0x14] <+6>: int $0x1a
# CHECK-NEXT: command-disassemble.s.tmp[0x16] <+8>: int $0x1b
# CHECK-NEXT: command-disassemble.s.tmp[0x18] <+10>: int $0x1c
# CHECK-NEXT: command-disassemble.s.tmp[0x1a] <+12>: int $0x1d
# CHECK-NEXT: command-disassemble.s.tmp[0x1c] <+14>: int $0x1e
# CHECK-NEXT: command-disassemble.s.tmp[0x1e] <+16>: int $0x1f
# CHECK-NEXT: (lldb) disassemble --start-address 0x4 --end-address 0x8
# CHECK-NEXT: command-disassemble.s.tmp`foo:
# CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12
# CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13
# CHECK-NEXT: (lldb) disassemble --start-address 0x8 --end-address 0x4
# 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[0x2] <+2>: int $0x11
# CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12
# CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13
# 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 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, start/stop addresses or use the --force option.
# 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 --address 0x100 --force
# CHECK-NEXT: command-disassemble.s.tmp`very_long:
# CHECK-NEXT: command-disassemble.s.tmp[0x40] <+0>: int $0x2a
# 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[0x2] <+2>: int $0x11
# CHECK-NEXT: command-disassemble.s.tmp[0x4] <+4>: int $0x12
# CHECK-NEXT: command-disassemble.s.tmp[0x6] <+6>: int $0x13
# 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 --start-address 0x0 --end-address 0x20 --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, start/stop addresses or use the --force option.
# 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, start/stop addresses or use the --force option.
# CHECK-NEXT: Not disassembling a range because it is very large [0x0000000000006046-0x0000000000008046). To disassemble specify an instruction count limit, start/stop addresses or use the --force option.
# 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:
int $0x10
int $0x11
int $0x12
int $0x13
int $0x14
int $0x15
int $0x16
bar:
int $0x17
int $0x18
int $0x19
int $0x1a
int $0x1b
int $0x1c
int $0x1d
int $0x1e
int $0x1f
int $0x20
int $0x21
int $0x22
int $0x23
int $0x24
int $0x25
int $0x26
int $0x27
int $0x28
int $0x29
int $0x2a
int $0x2b
int $0x2c
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
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