Clang-compiled object files currently don't include the symbol sizes and
types. Some tools however need that information. For example, ctfconvert
uses that information to generate FreeBSD's CTF representation from ELF
files.
With this patch, symbol sizes and types are included in object files.
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Reported-by: Yutaro Hayakawa <yhayakawa3720@gmail.com>
llvm-svn: 342556
Fix bug https://bugs.llvm.org/show_bug.cgi?id=38643
In BPFAsmBackend applyFixup(), there is an assertion for FixedValue to be 0.
This may not be true, esp. for optimiation level 0.
For example, in the above bug, for the following two
static variables:
@bpf_map_lookup_elem = internal global i8* (i8*, i8*)*
inttoptr (i64 1 to i8* (i8*, i8*)*), align 8
@bpf_map_update_elem = internal global i32 (i8*, i8*, i8*, i64)*
inttoptr (i64 2 to i32 (i8*, i8*, i8*, i64)*), align 8
The static variable @bpf_map_update_elem will have a symbol
offset of 8 and a FK_SecRel_8 with FixupValue 8 will cause
the assertion if llvm is built with -DLLVM_ENABLE_ASSERTIONS=ON.
The above relocations will not exist if the program is compiled
with optimization level -O1 and above as the compiler optimizes
those static variables away. In the below error message, -O2
is suggested as this is the common practice.
Note that FixedValue = 0 in applyFixup() does exist and is valid,
e.g., for the global variable my_map in the above bug. The bpf
loader will process them properly for map_id's before loading
the program into the kernel.
The static variables, which are not optimized away by compiler,
may have FK_SecRel_8 relocation with non-zero FixedValue.
The patch removed the offending assertion and will issue
a hard error as below if the FixedValue in applyFixup()
is not 0.
$ llc -march=bpf -filetype=obj fixup.ll
LLVM ERROR: Unsupported relocation: try to compile with -O2 or above,
or check your static variable usage
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 340455
On targets like Arm some relaxations may only be performed when certain
architectural features are available. As functions can be compiled with
differing levels of architectural support we must make a judgement on
whether we can relax based on the MCSubtargetInfo for the function. This
change passes through the MCSubtargetInfo for the function to
fixupNeedsRelaxation so that the decision on whether to relax can be made
per function. In this patch, only the ARM backend makes use of this
information. We must also pass the MCSubtargetInfo to applyFixup because
some fixups skip error checking on the assumption that relaxation has
occurred, to prevent code-generation errors applyFixup must see the same
MCSubtargetInfo as fixupNeedsRelaxation.
Differential Revision: https://reviews.llvm.org/D44928
llvm-svn: 334078
With this we gain a little flexibility in how the generic object
writer is created.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47045
llvm-svn: 332868
To make this work I needed to add an endianness field to MCAsmBackend
so that writeNopData() implementations know which endianness to use.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47035
llvm-svn: 332857
Provide some free functions to reduce verbosity of endian-writing
a single value, and replace the endianness template parameter with
a field.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47032
llvm-svn: 332757
The idea is that a client that wants split dwarf would create a
specific kind of object writer that creates two files, and use it to
create the streamer.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47050
llvm-svn: 332749
Commit e4507fb8c94b ("bpf: disable DwarfUsesRelocationsAcrossSections")
disables MCAsmInfo DwarfUsesRelocationsAcrossSections unconditionally
so that dwarf will not use cross section (between dwarf and symbol table)
relocations. This new debug format enables pahole to dump structures
correctly as libdwarves.so does not have BPF backend support yet.
This new debug format, however, breaks bcc (https://github.com/iovisor/bcc)
source debug output as llvm in-memory Dwarf support has some issues to
handle it. More specifically, with DwarfUsesRelocationsAcrossSections
disabled, JIT compiler does not generate .debug_abbrev and Dwarf
DIE (debug info entry) processing is not happy about this.
This patch introduces a new flag -mattr=dwarfris
(dwarf relocation in section) to disable DwarfUsesRelocationsAcrossSections.
DwarfUsesRelocationsAcrossSections is true by default.
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 326505
The pahole does not work with BPF backend properly:
-bash-4.2$ cat test.c
struct test_t {
int a;
int b;
};
int test(struct test_t *s) {
return s->a;
}
-bash-4.2$ clang -g -O2 -target bpf -c test.c
-bash-4.2$ pahole test.o
struct clang version 7.0.0 (trunk 325446) (llvm/trunk 325464) {
clang version 7.0.0 (trunk 325446) (llvm/trunk 325464) clang version 7.0.0 (trunk 325446) (llvm/trunk 325464); /* 0 4 */
clang version 7.0.0 (trunk 325446) (llvm/trunk 325464) clang version 7.0.0 (trunk 325446) (llvm/trunk 325464); /* 4 4 */
/* size: 8, cachelines: 1, members: 2 */
/* last cacheline: 8 bytes */
};
-bash-4.2$
The reason is that BPF backend is not yet implemented in elfutils backend
https://github.com/threatstack/elfutils/tree/master/backends
and pahole depends on elfutils for dwarf parsing and resolving relocation.
More specifically, the unsupported relocation in .debug_info for type/member name
against symbol table caused the incorrect result above. The following is
the raw .rel.debug_info for the above example,
Hex dump of section '.rel.debug_info':
0x00000000 06000000 00000000 0a000000 0b000000 ................
0x00000010 0c000000 00000000 0a000000 01000000 ................
0x00000020 12000000 00000000 0a000000 02000000 ................
0x00000030 16000000 00000000 0a000000 0e000000 ................
0x00000040 1a000000 00000000 0a000000 03000000 ................
----------------- -------- --------
reloc location type symtab index
Hex dump of section '.debug_info':
0x00000000 7b000000 04000000 00000801 00000000 {...............
0x00000010 0c000000 00000000 00000000 00000000 ................
0x00000020 00000000 00001000 00000200 00000000 ................
Based on "type", the proper value will be extracted from symbol table
and filled in .debug_info so later on .debug_info can be properly
resolved against debug strings.
There are two ways to fix this problem. One is to fix elfutils by adding
BPF support which is desirable. This could take a long time and won't work
with already deployed pahole. For a short term workaround, we can disable
dwarf cross-section relation which specifically avoids debug_info and
symbol table cross relocation. This should help any dwarf-related tool
which has not implement BPF specific relocations yet.
Now .rel.debug_info does not have any relocation for symbol table and
.debug_info itself contains necessary relocation information by itself.
Hex dump of section '.debug_info':
0x00000000 7b000000 04000000 00000801 00000000 {...............
0x00000010 0c003700 00000000 00003e00 00000000 ..7.......>.....
0x00000020 00000000 00001000 00000200 00000000 ................
location 0xc has 0, 0x12 has 0x37, 0x1a has 0x3e in place which
will be used in relocation resolution. Here, the values of 0, 0x37 and 0x3e
are offset in .debug_str section.
Please note the difference between two above .debug_info dumps.
With the fix, pahole works properly with BPF backend:
-bash-4.2$ clang -O2 -g -target bpf -c test.c
-bash-4.2$ pahole test.o
struct test_t {
int a; /* 0 4 */
int b; /* 4 4 */
/* size: 8, cachelines: 1, members: 2 */
/* last cacheline: 8 bytes */
};
Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 325735
Currently it's not possible to access MCSubtargetInfo from a TgtMCAsmBackend.
D20830 threaded an MCSubtargetInfo reference through
MCAsmBackend::relaxInstruction, but this isn't the only function that would
benefit from access. This patch removes the Triple and CPUString arguments
from createMCAsmBackend and replaces them with MCSubtargetInfo.
This patch just changes the interface without making any intentional
functional changes. Once in, several cleanups are possible:
* Get rid of the awkward MCSubtargetInfo handling in ARMAsmBackend
* Support 16-bit instructions when valid in MipsAsmBackend::writeNopData
* Get rid of the CPU string parsing in X86AsmBackend and just use a SubtargetFeature for HasNopl
* Emit 16-bit nops in RISCVAsmBackend::writeNopData if the compressed instruction set extension is enabled (see D41221)
This change initially exposed PR35686, which has since been resolved in r321026.
Differential Revision: https://reviews.llvm.org/D41349
llvm-svn: 321692
kernel verifier is becoming smarter and soon will support
direct and indirect function calls.
Remove obsolete error from BPF backend.
Make call to use PCRel_4 fixup.
'bpf to bpf' calls are distinguished from 'bpf to kernel' calls
by insn->src_reg == BPF_PSEUDO_CALL == 1 which is used as relocation
indicator similar to ld_imm64->src_reg == BPF_PSEUDO_MAP_FD == 1
The actual 'call' instruction remains the same for both
'bpf to kernel' and 'bpf to bpf' calls.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 318614
Add hook in BPF backend so that llvm-objdump can print out
the jmp target with label names, e.g.,
...
if r1 != 2 goto 6 <LBB0_2>
...
goto 7 <LBB0_4>
...
LBB0_2:
...
LBB0_4:
...
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 318358
MCObjectStreamer owns its MCCodeEmitter -- this fixes the types to reflect that,
and allows us to remove the last instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315531
MCObjectStreamer owns its MCAsmBackend -- this fixes the types to reflect that,
and allows us to remove another instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315410
functions.
This makes the ownership of the resulting MCObjectWriter clear, and allows us
to remove one instance of MCObjectStreamer's bizarre "holding ownership via
someone else's reference" trick.
llvm-svn: 315327
ELFObjectWriter's constructor.
Fixes the same ownership issue for ELF that r315245 did for MachO:
ELFObjectWriter takes ownership of its MCELFObjectTargetWriter, so we want to
pass this through to the constructor via a unique_ptr, rather than a raw ptr.
llvm-svn: 315254
The issue is not if the value is pcrel. It is whether we have a
relocation or not.
If we have a relocation, the static linker will select the upper
bits. If we don't have a relocation, we have to do it.
llvm-svn: 307730
processFixupValue is called on every relaxation iteration. applyFixup
is only called once at the very end. applyFixup is then the correct
place to do last minute changes and value checks.
While here, do proper range checks again for fixup_arm_thumb_bl. We
used to do it, but dropped because of thumb2. We now do it again, but
use the thumb2 range.
llvm-svn: 306177
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
o Add bpfeb support in BPF dwarfdump unit test case
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@fb.com>
llvm-svn: 302265
A number of backends (AArch64, MIPS, ARM) have been using
MCContext::reportError to report issues such as out-of-range fixup values in
their TgtAsmBackend. This is great, but because MCContext couldn't easily be
threaded through to the adjustFixupValue helper function from its usual
callsite (applyFixup), these backends ended up adding an MCContext* argument
and adding another call to applyFixup to processFixupValue. Adding an
MCContext parameter to applyFixup makes this unnecessary, and even better -
applyFixup can take a reference to MCContext rather than a potentially null
pointer.
Differential Revision: https://reviews.llvm.org/D30264
llvm-svn: 299529
- teach RelocVisitor to recognize bpf relocations
- fix AsmInfo->PointerSize to make sure dwarf is emitted correctly
- add a test for the above
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 287521
Summary:
* ARM is omitted from this patch because this check appears to expose bugs in this target.
* Mips is omitted from this patch because this check either detects bugs or deliberate
emission of instructions that don't satisfy their predicates. One deliberate
use is the SYNC instruction where the version with an operand is correctly
defined as requiring MIPS32 while the version without an operand is defined
as an alias of 'SYNC 0' and requires MIPS2.
* X86 is omitted from this patch because it doesn't use the tablegen-erated
MCCodeEmitter infrastructure.
Patches for ARM and Mips will follow.
Depends on D25617
Reviewers: tstellarAMD, jmolloy
Subscribers: wdng, jmolloy, aemerson, rengolin, arsenm, jyknight, nemanjai, nhaehnle, tstellarAMD, llvm-commits
Differential Revision: https://reviews.llvm.org/D25618
llvm-svn: 287439
Some targets, notably AArch64 for ILP32, have different relocation encodings
based upon the ABI. This is an enabling change, so a future patch can use the
ABIName from MCTargetOptions to chose which relocations to use. Tested using
check-llvm.
The corresponding change to clang is in: http://reviews.llvm.org/D16538
Patch by: Joel Jones
Differential Revision: https://reviews.llvm.org/D16213
llvm-svn: 276654
The same value for EM_BPF is being propagated to glibc,
elfutils, and binutils.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 275633
MCSymbol.h shouldn't pull in MCAssembler.h, just MCFragment.h.
MCLinkerOptimizationHint.h shouldn't need MCMachObjectWriter.h. The
rest is fixing the fallout.
llvm-svn: 273507
Removed some unused headers, replaced some headers with forward class declarations.
Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'
Patch by Eugene Kosov <claprix@yandex.ru>
Differential Revision: http://reviews.llvm.org/D19219
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html
"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi
Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark
Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D16471
llvm-svn: 258861
Summary:
This is the first patch in the series to migrate Triple's (which are ambiguous)
to TargetTuple's (which aren't).
For the moment, TargetTuple simply passes all requests to the Triple object it
holds. Once it has replaced Triple, it will start to implement the interface in
a more suitable way.
This change makes some changes to the public C++ API. In particular,
InitMCSubtargetInfo(), createMCRelocationInfo(), and createMCSymbolizer()
now take TargetTuples instead of Triples. The other public C++ API's have
been left as-is for the moment to reduce patch size.
This commit also contains a trivial patch to clang to account for the C++ API
change. Thanks go to Pavel Labath for fixing LLDB for me.
Reviewers: rengolin
Subscribers: jyknight, dschuff, arsenm, rampitec, danalbert, srhines, javed.absar, dsanders, echristo, emaste, jholewinski, tberghammer, ted, jfb, llvm-commits, rengolin
Differential Revision: http://reviews.llvm.org/D10969
llvm-svn: 247692
Summary:
This is the first patch in the series to migrate Triple's (which are ambiguous)
to TargetTuple's (which aren't).
For the moment, TargetTuple simply passes all requests to the Triple object it
holds. Once it has replaced Triple, it will start to implement the interface in
a more suitable way.
This change makes some changes to the public C++ API. In particular,
InitMCSubtargetInfo(), createMCRelocationInfo(), and createMCSymbolizer()
now take TargetTuples instead of Triples. The other public C++ API's have
been left as-is for the moment to reduce patch size.
This commit also contains a trivial patch to clang to account for the C++ API
change.
Reviewers: rengolin
Subscribers: jyknight, dschuff, arsenm, rampitec, danalbert, srhines, javed.absar, dsanders, echristo, emaste, jholewinski, tberghammer, ted, jfb, llvm-commits, rengolin
Differential Revision: http://reviews.llvm.org/D10969
llvm-svn: 247683
Force all creators of `MCSubtargetInfo` to immediately initialize it,
merging the default constructor and the initializer into an initializing
constructor. Besides cleaning up the code a little, this makes it clear
that the initializer is never called again later.
Out-of-tree backends need a trivial change: instead of calling:
auto *X = new MCSubtargetInfo();
InitXYZMCSubtargetInfo(X, ...);
return X;
they should call:
return createXYZMCSubtargetInfoImpl(...);
There's no real functionality change here.
llvm-svn: 241957
Summary:
This concludes the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.
At this point, the StringRef-form of GNU Triples should only be used in the
public API (including IR serialization) and a couple objects that directly
interact with the API (most notably the Module class). The next step is to
replace these Triple objects with the TargetTuple object that will represent
our authoratative/unambiguous internal equivalent to GNU Triples.
Reviewers: rengolin
Subscribers: llvm-commits, jholewinski, ted, rengolin
Differential Revision: http://reviews.llvm.org/D10962
llvm-svn: 241472
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
llvm-svn: 240137
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.
Reviewers: rafael
Reviewed By: rafael
Subscribers: rafael, ted, jfb, llvm-commits, rengolin, jholewinski
Differential Revision: http://reviews.llvm.org/D10311
llvm-svn: 239467
Yonghong Song