This patch adds in support for symbolizing PGO information contained
within the SHT_LLVM_BB_ADDR_MAP section in llvm-objdump. The outputs are
simply the raw values contained within the section.
When a section contains two functions x1 and x2, we incorrectly display
x1's relocations when dumping x2 for `--disassemble-symbols=x2 -r`.
Fix#75539 by ignoring these relocations.
llvm-readobj and llvm-objdump have inconsistent handling of display
lma for sections.
This patch tries to common code up and adapt the same approach for
both tools.
Add a shouldAdjustVA(Section) guard on top of address update.
Update llvm-objdump file to update symbol table when --adjust-vma used.
Fixes#63203
Patch by HamidrezaSK (Hamidreza Sanaee)
Summary:
Adding a new option -traceback-table to print out the traceback info of xcoff ojbect file.
Reviewers: James Henderson, Fangrui Song, Stephen Peckham, Xing Xue
Differential Revision: https://reviews.llvm.org/D89049
They will demonstrate some symbol that --adjust-vma= should not adjust.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D153401
This is a follow-up to b71edfaa4ec3c998aadb35255ce2f60bba2940b0
since I forgot the lit.local.cfg files in that one.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: barannikov88, kwk
Differential Revision: https://reviews.llvm.org/D150762
If a symbol needs both JUMP_SLOT and GLOB_DAT relocations, there is a
minor linker optimization to keep just GLOB_DAT. This optimization
is only implemented by GNU ld's x86 port and mold.
https://maskray.me/blog/2021-08-29-all-about-global-offset-table#combining-.got-and-.got.plt
With the optimizing, the PLT entry is placed in .plt.got and the
associated GOTPLT entry is placed in .got (ld.bfd -z now) or .got.plt (ld.bfd -z lazy).
The relocation is in .rel[a].dyn.
This patch synthesizes `symbol@plt` labels for these .plt.got entries.
Example:
```
cat > a.s <<e
.globl _start; _start:
mov combined0@gotpcrel(%rip), %rax; mov combined1@gotpcrel(%rip), %rax
call combined0@plt; call combined1@plt
call foo0@plt; call foo1@plt
e
cat > b.s <<e
.globl foo0, foo1, combined0, combined1
foo0: foo1: combined0: combined1:
e
gcc -fuse-ld=bfd -shared b.s -o b.so
gcc -fuse-ld=bfd -pie -nostdlib a.s b.so -o a
```
```
Disassembly of section .plt:
0000000000001000 <.plt>:
1000: ff 35 ea 1f 00 00 pushq 0x1fea(%rip) # 0x2ff0 <_GLOBAL_OFFSET_TABLE_+0x8>
1006: ff 25 ec 1f 00 00 jmpq *0x1fec(%rip) # 0x2ff8 <_GLOBAL_OFFSET_TABLE_+0x10>
100c: 0f 1f 40 00 nopl (%rax)
0000000000001010 <foo1@plt>:
1010: ff 25 ea 1f 00 00 jmpq *0x1fea(%rip) # 0x3000 <_GLOBAL_OFFSET_TABLE_+0x18>
1016: 68 00 00 00 00 pushq $0x0
101b: e9 e0 ff ff ff jmp 0x1000 <.plt>
0000000000001020 <foo0@plt>:
1020: ff 25 e2 1f 00 00 jmpq *0x1fe2(%rip) # 0x3008 <_GLOBAL_OFFSET_TABLE_+0x20>
1026: 68 01 00 00 00 pushq $0x1
102b: e9 d0 ff ff ff jmp 0x1000 <.plt>
Disassembly of section .plt.got:
0000000000001030 <combined0@plt>:
1030: ff 25 a2 1f 00 00 jmpq *0x1fa2(%rip) # 0x2fd8 <foo1+0x2fd8>
1036: 66 90 nop
0000000000001038 <combined1@plt>:
1038: ff 25 a2 1f 00 00 jmpq *0x1fa2(%rip) # 0x2fe0 <foo1+0x2fe0>
103e: 66 90 nop
```
For x86-32, with -z now, if we remove `foo0` and `foo1`, the absence of regular
PLT will cause GNU ld to omit .got.plt, and our code cannot synthesize @plt
labels. This is an extreme corner case that almost never happens in practice (to
trigger the case, ensure every PLT symbol has been taken address). To fix it, we
can get the `_GLOBAL_OFFSET_TABLE_` symbol value, but the complexity is not
worth it.
Close https://github.com/llvm/llvm-project/issues/62537
Reviewed By: bd1976llvm
Differential Revision: https://reviews.llvm.org/D149817
Currently when using the LLVM tools (eg llvm-readobj, llvm-objdump) to
find information about basic block locations using the propeller tooling
in relocatable object files function addresses are not mapped properly
which causes problems. In llvm-readobj this means that incorrect
function names will be pulled. In llvm-objdum this means that most BBs
won't show up in the output if --symbolize-operands is used. This patch
changes the behavior of decodeBBAddrMap to trace through relocations
to get correct function addresses if it is going through a relocatable
object file. This fixes the behavior in both tools and also other
consumers of decodeBBAddrMap. Some helper functions have been added
in/refactoring done to aid in grabbing BB address map sections now that
in some cases both relocation and BB address map sections need to be
obtained at the same time.
Regression tests moved around/added.
Differential Revision: https://reviews.llvm.org/D143841
Let Propeller use specialized IDs for basic blocks, instead of MBB number.
This allows optimizations not just prior to asm-printer, but throughout the entire codegen.
This patch only implements the functionality under the new `LLVM_BB_ADDR_MAP` version, but the old version is still being used. A later patch will change the used version.
####Background
Today Propeller uses machine basic block (MBB) numbers, which already exist, to map native assembly to machine IR. This is done as follows.
- Basic block addresses are captured and dumped into the `LLVM_BB_ADDR_MAP` section just before the AsmPrinter pass which writes out object files. This ensures that we have a mapping that is close to assembly.
- Profiling mapping works by taking a virtual address of an instruction and looking up the `LLVM_BB_ADDR_MAP` section to find the MBB number it corresponds to.
- While this works well today, we need to do better when we scale Propeller to target other Machine IR optimizations like spill code optimization. Register allocation happens earlier in the Machine IR pipeline and we need an annotation mechanism that is valid at that point.
- The current scheme will not work in this scenario because the MBB number of a particular basic block is not fixed and changes over the course of codegen (via renumbering, adding, and removing the basic blocks).
- In other words, the volatile MBB numbers do not provide a one-to-one correspondence throughout the lifetime of Machine IR. Profile annotation using MBB numbers is restricted to a fixed point; only valid at the exact point where it was dumped.
- Further, the object file can only be dumped before AsmPrinter and cannot be dumped at an arbitrary point in the Machine IR pass pipeline. Hence, MBB numbers are not suitable and we need something else.
####Solution
We propose using fixed unique incremental MBB IDs for basic blocks instead of volatile MBB numbers. These IDs are assigned upon the creation of machine basic blocks. We modify `MachineFunction::CreateMachineBasicBlock` to assign the fixed ID to every newly created basic block. It assigns `MachineFunction::NextMBBID` to the MBB ID and then increments it, which ensures having unique IDs.
To ensure correct profile attribution, multiple equivalent compilations must generate the same Propeller IDs. This is guaranteed as long as the MachineFunction passes run in the same order. Since the `NextBBID` variable is scoped to `MachineFunction`, interleaving of codegen for different functions won't cause any inconsistencies.
The new encoding is generated under the new version number 2 and we keep backward-compatibility with older versions.
####Impact on Size of the `LLVM_BB_ADDR_MAP` Section
Emitting the Propeller ID results in a 23% increase in the size of the `LLVM_BB_ADDR_MAP` section for the clang binary.
Reviewed By: tmsriram
Differential Revision: https://reviews.llvm.org/D100808
This was previously attempted in 2016 by colinl's D18770, but LLD tests
were missed, which caused the change to be reverted.
Setting --print-imm-hex by default brings llvm-objdump's behavior closer
in line with objdump, and it makes it easier to read addresses and
alignment from the disassembly. It may make non-address immediates
harder to interpret, but it still seems the better default, barring more
context-sensitive base selection logic.
Differential Revision: https://reviews.llvm.org/D136972
This prepares for an upcoming change to make --print-imm-hex the default
behavior of llvm-objdump. These tests were updated in a semi-automatic
fashion.
See D136972 for details.
The output is similar to objdump --no-addresses since binutils 2.35.
Depends on D135039
Close#58088
Differential Revision: https://reviews.llvm.org/D135040
It seems to make sense to omit offsets when --no-leading-addr is specified. The output is now closer
to objdump -dr --no-addresses (non-wide output).
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D135039
It doesn't have a section header string table so add a vector to have
the strings and create name based on the program header type and the
index.
Differential Revision: https://reviews.llvm.org/D131290
When linking, using `-Wl,-z,keep-text-section-prefix` results in multiple text sections while all `SHT_LLVM_BB_ADDR_MAP` sections are linked into a single one.
In such case, we should not read the corresponding section for each text section, and instead read all `SHT_LLVM_BB_ADDR_MAP` sections before disassembly.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D129924
The linux perf tools use /proc/kcore for disassembly kernel functions.
Actually it copies the relevant parts to a temp file and then pass it to
objdump. But it doesn't have section headers so llvm-objdump cannot
handle it.
Let's create fake section headers for the program headers. It'd have a
single section for each segment to cover the entire range. And for this
purpose we can consider only executable code segments.
With this change, I can see the following command shows proper outputs.
perf annotate --stdio --objdump=/path/to/llvm-objdump
Differential Revision: https://reviews.llvm.org/D128705
This is a resurrection of D106421 with the change that it keeps backward-compatibility. This means decoding the previous version of `LLVM_BB_ADDR_MAP` will work. This is required as the profile mapping tool is not released with LLVM (AutoFDO). As suggested by @jhenderson we rename the original section type value to `SHT_LLVM_BB_ADDR_MAP_V0` and assign a new value to the `SHT_LLVM_BB_ADDR_MAP` section type. The new encoding adds a version byte to each function entry to specify the encoding version for that function. This patch also adds a feature byte to be used with more flexibility in the future. An use-case example for the feature field is encoding multi-section functions more concisely using a different format.
Conceptually, the new encoding emits basic block offsets and sizes as label differences between each two consecutive basic block begin and end label. When decoding, offsets must be aggregated along with basic block sizes to calculate the final offsets of basic blocks relative to the function address.
This encoding uses smaller values compared to the existing one (offsets relative to function symbol).
Smaller values tend to occupy fewer bytes in ULEB128 encoding. As a result, we get about 17% total reduction in the size of the bb-address-map section (from about 11MB to 9MB for the clang PGO binary).
The extra two bytes (version and feature fields) incur a small 3% size overhead to the `LLVM_BB_ADDR_MAP` section size.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D121346
`--symbolize-operands` already symbolizes branch targets based on the disassembly. When the object file is created with `-fbasic-block-sections=labels` (ELF-only) it will include a SHT_LLVM_BB_ADDR_MAP section which maps basic blocks to their addresses. In such case `llvm-objdump` can annotate the disassembly based on labels inferred on this section.
In contrast to the current labels, SHT_LLVM_BB_ADDR_MAP-based labels are created for every machine basic block including empty blocks and those which are not branched into (fallthrough blocks).
The old logic is still executed even when the SHT_LLVM_BB_ADDR_MAP section is present to handle functions which have not been received an entry in this section.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D124560
In the command guide --prefix and --prefix-strip is used in the form
--prefix=<prefix> however currently it is used in the form --prefix
<prefix>. This change fixes these options to match the command guide.
Differential Revision: https://reviews.llvm.org/D110551
* Add a newline before `DYNAMIC RELOCATION RECORDS` (see D101796)
* Add the missing `OFFSET TYPE VALUE` line
* Align columns
Note: llvm-readobj/ELFDumper.cpp `loadDynamicTable` has sophisticated PT_DYNAMIC
code which is unavailable in llvm-objdump.
Reviewed By: jhenderson, Higuoxing
Differential Revision: https://reviews.llvm.org/D110595
Print relocations interleaved with disassembled instructions for
executables with relocatable sections, e.g. those built with "-Wl,-q".
Differential Revision: https://reviews.llvm.org/D109016
llvm-objdump had some missing coverage that is fixed by this change:
- A test specifically for --print-imm-hex, and coverage of --no-print-imm-hex
- section-headers.test checks the aliases --headers or --section-headers
- A test for the use of --private-headers for ELF that checks the output
- A test for ELF program headers
Differential Revision: https://reviews.llvm.org/D103974
The patch reuses the common code to print memory operand addresses as
instruction comments. This helps to align the comments and enables using
target-specific comment markers when `evaluateMemoryOperandAddress()` is
implemented for them.
Differential Revision: https://reviews.llvm.org/D104861
For now, the source variable locations are printed at about the same
space as the comments for disassembled code, which can make some ranges
for variables disappear if a line contains comments, for example:
┠─ bar = W1
0: add x0, x2, #2, lsl #12 // =8192┃
4: add z31.d, z31.d, #65280 // =0xff00
8: nop ┻
The patch shifts the report a bit to allow printing comments up to
approximately 16 characters without interferences.
Differential Revision: https://reviews.llvm.org/D104700
LLVM disassembler can generate comments for disassembled instructions.
The patch enables printing these comments for 'llvm-objdump -d'.
Differential Revision: https://reviews.llvm.org/D104699
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.
This is a preliminary commit for https://reviews.llvm.org/D99080
The internal `cl::opt` option --x86-asm-syntax sets the AsmParser and AsmWriter
dialect. The option is used by llc and llvm-mc tests to set the AsmWriter dialect.
This patch adds -M {att,intel} as GNU objdump compatible aliases (PR43413).
Note: the dialect is initialized when the MCAsmInfo is constructed.
`MCInstPrinter::applyTargetSpecificCLOption` is called too late and its MCAsmInfo
reference is const, so changing the `cl::opt` in
`MCInstPrinter::applyTargetSpecificCLOption` is not an option, at least without
large amount of refactoring.
Reviewed By: hoy, jhenderson, thakis
Differential Revision: https://reviews.llvm.org/D101695
When dumping multiple pieces of information (e.g. --all-headers),
there is sometimes no separator between two pieces.
This patch uses the "\nheader:\n" style, which generally improves
compatibility with GNU objdump.
Note: objdump -t/-T does not add a newline before "SYMBOL TABLE:" and "DYNAMIC SYMBOL TABLE:".
We add a newline to be consistent with other information.
`objdump -d` prints two empty lines before the first 'Disassembly of section'.
We print just one with this patch.
Differential Revision: https://reviews.llvm.org/D101796
Previously printing R_386_RELATIVE relocations would trigger
`error: can't read an entry at 0x40: it goes past the end of the section (0x40)`
I found this while writing a test case for LLD (D100490).
This also includes some minor cleanup in the elf-dynamic-relcos.test
llvm-objdump test based on the newly added test.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D100489
This is similar to D83530, but for llvm-objdump.
The motivation is the desire to add an `llvm-otool` symlink to
llvm-objdump that behaves like macOS's `otool`, using the same
technique the at llvm-objcopy uses to behave like `strip` (etc).
This change for the most part preserves behavior. In some cases,
it increases compatibility with GNU objdump a bit. For example,
the long options now require two dashes, and the long options
taking arguments for the most part now require a `=` in front
of the value. Exceptions are flags where tests passed the
value separately, for these the separate form is kept as
an alias to the = form.
The one-letter short form args are now joined or separate
and long longer accept a =, which also matches GNU objdump.
cl::opt<>s in libraries now have to be explicitly plumbed
through. This patch does that for --x86-asm-syntax=, but
there's hope that we can remove that again.
Differential Revision: https://reviews.llvm.org/D100433
Clang spends a decent amount of time in the LineOffsetMapping::get(...)
function. This function used to be vectorized (through SSE2) then the
optimization got dropped because the sequential version was on-par performance
wise.
This provides an optimization of the sequential version that works on a word at
a time, using (documented) bithacks to provide a portable vectorization.
When preprocessing the sqlite amalgamation, this yields a sweet 3% speedup.
Differential Revision: https://reviews.llvm.org/D99409
The option `--prefix-strip` is only used when `--prefix` is not empty.
It removes N initial directories from absolute paths before adding the
prefix.
This matches GNU's objdump behavior.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D96679
Merging directories and files may produce different results on different
platforms.
Merging "./Inputs" and "source-interleave-x86_64.c" will use different
separators in POSIX and Windows.
Dedicated tests are needed for dealing with removing trailing separators
for POSIX (consider only '/') and Windows (consider '/' and '\').
Fixes D85024.
Fixes PR46368.
Reviewed By: jhenderson, MaskRay
Differential revision: https://reviews.llvm.org/D95513
Warnings have been added for three cases (PR41905): (1) missing debug info, (2)
the source file cannot be found, (3) the debug info points at a line beyond the
end of the file.
(1) is probably less useful. This was brought up once on
http://lists.llvm.org/pipermail/llvm-dev/2020-April/141264.html and two
internal users mentioned it to me that it was annoying. (I personally
find the warning confusing, too.)
Users specify --source to get additional information if sources happen to be
available. If sources are not available, it should be obvious as the output
will have no interleaved source lines. The warning can be especially annoying
when using llvm-objdump -S on a bunch of files.
This patch drops the warning when there is no debug info.
(If LLVMSymbolizer::symbolizeCode returns an `Error`, there will still be
an error. There is currently no test for an `Error` return value.
The only code path is probably a broken symbol table, but we probably already emit a warning
in that case)
`source-interleave-prefix.test` has an inappropriate "malformed" test - the test simply has no
.debug_* because new llc does not produce debug info when the filename is empty (invalid).
I have tried tampering the header of .debug_info/.debug_line but llvm-symbolizer does not warn.
This patch does not intend to add the missing test coverage.
Differential Revision: https://reviews.llvm.org/D88715
For x86-64 the REX.w prefix takes precedence over any other size
override (i.e. 0x66). Therefore, for x86-64 when REX.w is present set
'hasOpSize' to false to ensure that any size override is ignored.
Fixes PR48901.
Differential Revision: https://reviews.llvm.org/D95682
Imagine we have a YAML declaration of few sections: `foo1`, `<unnamed 2>`, `foo3`, `foo4`.
To put them into segment we can do (1*):
```
Sections:
- Section: foo1
- Section: foo4
```
or we can use (2*):
```
Sections:
- Section: foo1
- Section: foo3
- Section: foo4
```
or (3*) :
```
Sections:
- Section: foo1
## "(index 2)" here is a name that we automatically created for a unnamed section.
- Section: (index 2)
- Section: foo3
- Section: foo4
```
It looks really confusing that we don't have to list all of sections.
At first I've tried to make this rule stricter and report an error when there is a gap
(i.e. when a section is included into segment, but not listed explicitly).
This did not work perfect, because such approach conflicts with unnamed sections/fills (see (3*)).
This patch drops "Sections" key and introduces 2 keys instead: `FirstSec` and `LastSec`.
Both are optional.
Differential revision: https://reviews.llvm.org/D90458
