Windows ARM64 has PIC relocation model and uses jump table kind
EK_LabelDifference32. This produces jump table entry as
".word LBB123 - LJTI1_2" which represents the distance between the block
and jump table.
A new relocation type (IMAGE_REL_ARM64_REL32) is needed to do the fixup
correctly if they are in different COFF section.
This change saves the jump table to the same COFF section as the
associated code. An ideal fix could be utilizing IMAGE_REL_ARM64_REL32
relocation type.
Patch by Tom Tan!
Differential Revision: https://reviews.llvm.org/D57277
llvm-svn: 352465
Each hwasan check requires emitting a small piece of code like this:
https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html#memory-accesses
The problem with this is that these code blocks typically bloat code
size significantly.
An obvious solution is to outline these blocks of code. In fact, this
has already been implemented under the -hwasan-instrument-with-calls
flag. However, as currently implemented this has a number of problems:
- The functions use the same calling convention as regular C functions.
This means that the backend must spill all temporary registers as
required by the platform's C calling convention, even though the
check only needs two registers on the hot path.
- The functions take the address to be checked in a fixed register,
which increases register pressure.
Both of these factors can diminish the code size effect and increase
the performance hit of -hwasan-instrument-with-calls.
The solution that this patch implements is to involve the aarch64
backend in outlining the checks. An intrinsic and pseudo-instruction
are created to represent a hwasan check. The pseudo-instruction
is register allocated like any other instruction, and we allow the
register allocator to select almost any register for the address to
check. A particular combination of (register selection, type of check)
triggers the creation in the backend of a function to handle the check
for specifically that pair. The resulting functions are deduplicated by
the linker. The pseudo-instruction (really the function) is specified
to preserve all registers except for the registers that the AAPCS
specifies may be clobbered by a call.
To measure the code size and performance effect of this change, I
took a number of measurements using Chromium for Android on aarch64,
comparing a browser with inlined checks (the baseline) against a
browser with outlined checks.
Code size: Size of .text decreases from 243897420 to 171619972 bytes,
or a 30% decrease.
Performance: Using Chromium's blink_perf.layout microbenchmarks I
measured a median performance regression of 6.24%.
The fact that a perf/size tradeoff is evident here suggests that
we might want to make the new behaviour conditional on -Os/-Oz.
But for now I've enabled it unconditionally, my reasoning being that
hwasan users typically expect a relatively large perf hit, and ~6%
isn't really adding much. We may want to revisit this decision in
the future, though.
I also tried experimenting with varying the number of registers
selectable by the hwasan check pseudo-instruction (which would result
in fewer variants being created), on the hypothesis that creating
fewer variants of the function would expose another perf/size tradeoff
by reducing icache pressure from the check functions at the cost of
register pressure. Although I did observe a code size increase with
fewer registers, I did not observe a strong correlation between the
number of registers and the performance of the resulting browser on the
microbenchmarks, so I conclude that we might as well use ~all registers
to get the maximum code size improvement. My results are below:
Regs | .text size | Perf hit
-----+------------+---------
~all | 171619972 | 6.24%
16 | 171765192 | 7.03%
8 | 172917788 | 5.82%
4 | 177054016 | 6.89%
Differential Revision: https://reviews.llvm.org/D56954
llvm-svn: 351920
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
This patch supports MS SEH extensions __try/__except/__finally. The intrinsics localescape and localrecover are responsible for communicating escaped static allocas from the try block to the handler.
We need to preserve frame pointers for SEH. So we create a new function/property HasLocalEscape.
Reviewers: rnk, compnerd, mstorsjo, TomTan, efriedma, ssijaric
Reviewed By: rnk, efriedma
Subscribers: smeenai, jrmuizel, alex, majnemer, ssijaric, ehsan, dmajor, kristina, javed.absar, kristof.beyls, chrib, llvm-commits
Differential Revision: https://reviews.llvm.org/D53540
llvm-svn: 351370
- When signing return addresses with -msign-return-address=<scope>{+<key>},
either the A key instructions or the B key instructions can be used. To
correctly authenticate the return address, the unwinder/debugger must know
which key was used to sign the return address.
- When and exception is thrown or a break point reached, it may be necessary to
unwind the stack. To accomplish this, the unwinder/debugger must be able to
first authenticate an the return address if it has been signed.
- To enable this, the augmentation string of CIEs has been extended to allow
inclusion of a 'B' character. Functions that are signed using the B key
variant of the instructions should have and FDE whose associated CIE has a 'B'
in the augmentation string.
- One must also be able to preserve these semantics when first stepping from a
high level language into assembly and then, as a second step, into an object
file. To achieve this, I have introduced a new assembly directive
'.cfi_b_key_frame ', that tells the assembler the current frame uses return
address signing with the B key.
- This ensures that the FDE is associated with a CIE that has 'B' in the
augmentation string.
Differential Revision: https://reviews.llvm.org/D51798
llvm-svn: 349895
Summary:
Emit COFF header when printing out the function. This is important as the
header contains two important pieces of information: the storage class for the
symbol and the symbol type information. This bit of information is required for
the linker to correctly identify the type of symbol that it is dealing with.
This patch mimics X86 and ARM COFF behavior for function header emission.
Reviewers: rnk, mstorsjo, compnerd, TomTan, ssijaric
Reviewed By: mstorsjo
Subscribers: dmajor, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D55535
llvm-svn: 348875
Summary:
Add a hook to the GCMetadataPrinter for emitting stack maps in
custom format. The hook will be called at stack map generation
time. The default stack map format is used if there is no hook.
For this to be useful a few data structures and accessors are
exposed from the StackMaps class, so the custom printer can
access the stack map data.
This patch authored by Cherry Zhang <cherryyz@google.com>.
Reviewers: thanm, apilipenko, reames
Reviewed By: reames
Subscribers: reames, apilipenko, nemanjai, javed.absar, kbarton, jsji, llvm-commits
Differential Revision: https://reviews.llvm.org/D53892
llvm-svn: 347584
Add ARM64 unwind codes to MCLayer, as well SEH directives that will be emitted
by the frame lowering patch to follow. We only emit unwind codes into object
object files for now.
Differential Revision: https://reviews.llvm.org/D50166
llvm-svn: 345450
When branch target identification is enabled, all indirectly-callable
functions start with a BTI C instruction. this instruction can only be
the target of certain indirect branches (direct branches and
fall-through are not affected):
- A BLR instruction, in either a protected or unprotected page.
- A BR instruction in a protected page, using x16 or x17.
- A BR instruction in an unprotected page, using any register.
Without BTI, we can use any non call-preserved register to hold the
address for an indirect tail call. However, when BTI is enabled, then
the code being compiled might be loaded into a BTI-protected page, where
only x16 and x17 can be used for indirect tail calls.
Legacy code withiout this restriction can still indirectly tail-call
BTI-protected functions, because they will be loaded into an unprotected
page, so any register is allowed.
Differential revision: https://reviews.llvm.org/D52868
llvm-svn: 343968
The MachineOutliner for AArch64 transforms indirect calls into indirect
tail calls, replacing the call with the TCRETURNri pseudo-instruction.
This pseudo lowers to a BR, but has the isCall and isReturn flags set.
The problem is that TCRETURNri takes a tcGPR64 as the register argument,
to prevent indiret tail-calls from using caller-saved registers. The
indirect calls transformed by the outliner could use caller-saved
registers. This is fine, because the outliner ensures that the register
is available at all call sites. However, this causes a verifier failure
when the register is not in tcGPR64. The fix is to add a new
pseudo-instruction like TCRETURNri, but which accepts any GPR.
Differential revision: https://reviews.llvm.org/D52829
llvm-svn: 343959
Split the `zcz` feature into specific ones got GP and FP registers, `zcz-gp`
and `zcz-fp`, respectively, while retaining the original feature option to
mean both.
Differential revision: https://reviews.llvm.org/D52621
llvm-svn: 343354
In SVN r334523, the first half of comdat constant pool handling was
hoisted from X86WindowsTargetObjectFile (which despite the name only
was used for msvc targets) into the arch independent
TargetLoweringObjectFileCOFF, but the other half of the handling was
left behind in X86AsmPrinter::GetCPISymbol.
With only half of the handling in place, inconsistent comdat
sections/symbols are created, causing issues with both GNU binutils
(avoided for X86 in SVN r335918) and with the MS linker, which
would complain like this:
fatal error LNK1143: invalid or corrupt file: no symbol for COMDAT section 0x4
Differential Revision: https://reviews.llvm.org/D49644
llvm-svn: 337950
This patch re-introduces the "S" inline assembler constraint. This matches
an absolute symbolic address or a label reference. The primary use case is
asm("adrp %0, %1\n\t"
"add %0, %0, :lo12:%1" : "=r"(addr) : "S"(&var));
I say re-introduces as it seems like "S" was implemented in the original
AArch64 backend, but it looks like it wasn't carried forward to the merged
backend. The original implementation had A and L modifiers that could be
used to print ":lo12:" to the string. It looks like gcc doesn't use these
and :lo12: is expected to be written in the inline assembly string so I've
not implemented A and L. Clang already supports the S modifier.
Fixes PR37180
Differential Revision: https://reviews.llvm.org/D46745
llvm-svn: 332444
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Every known PE COFF target emits /EXPORT: linker flags into a .drective
section. The AsmPrinter should handle this.
While we're at it, use global_values() and emit each export flag with
its own .ascii directive. This should make the .s file output more
readable.
llvm-svn: 322788
For Cylone, the instruction "movi.2d vD, #0" is executed incorrectly in some rare
circumstances. Work around the issue conservatively by avoiding the instruction entirely.
This patch changes CodeGen so that problematic instructions are never
generated, and the AsmParser so that an equivalent instruction is used (with a
warning).
llvm-svn: 320965
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).
llvm-svn: 318490
This is similar to what was done for ARM in SVN r269574; the code
and the test are straight copypaste to the corresponding AArch64
code and test directory.
Differential revision: https://reviews.llvm.org/D37204
llvm-svn: 312223
Instead of loading 0 from a constant pool, it's of course much better to
materialize it using an fmov and the zero register.
Thanks to Ahmed Bougacha for the suggestion.
Differential Revision: https://reviews.llvm.org/D37102
llvm-svn: 311662
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
Summary:
This is used in the Linux kernel, and effectively just means "print an
address". This brings back r193593.
Reviewed by: Renato Golin
Reviewers: t.p.northover, rengolin, richard.barton.arm, kristof.beyls
Subscribers: aemerson, javed.absar, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D33558
llvm-svn: 303901
Remove "_NC" suffix and semantics from TLSDESC_LD{64,32}_LO12 and
TLSDESC_ADD_LO12 relocations
Rearrange ordering in AArch64.def to follow relocation encoding
Fix name:
R_AARCH64_P32_LD64_GOT_LO12_NC => R_AARCH64_P32_LD32_GOT_LO12_NC
Add support for several "TLS", "TLSGD", and "TLSLD" relocations for
ILP32
Fix return values from isNonILP32reloc
Add implementations for
R_AARCH64_ADR_PREL_PG_HI21_NC, R_AARCH64_P32_LD32_GOT_LO12_NC,
R_AARCH64_P32_TLSIE_LD32_GOTTPREL_LO12_NC,
R_AARCH64_P32_TLSDESC_LD32_LO12, R_AARCH64_LD64_GOT_LO12_NC,
*TLSLD_LDST128_DTPREL_LO12, *TLSLD_LDST128_DTPREL_LO12_NC,
*TLSLE_LDST128_TPREL_LO12, *TLSLE_LDST128_TPREL_LO12_NC
Modify error messages to give name of equivalent relocation in the
ABI not being used, along with better checking for non-existent
requested relocations.
Added assembler support for "pg_hi21_nc"
Relocation definitions added without implementations:
R_AARCH64_P32_TLSDESC_ADR_PREL21, R_AARCH64_P32_TLSGD_ADR_PREL21,
R_AARCH64_P32_TLSGD_ADD_LO12_NC, R_AARCH64_P32_TLSLD_ADR_PREL21,
R_AARCH64_P32_TLSLD_ADR_PAGE21, R_AARCH64_P32_TLSLD_ADD_LO12_NC,
R_AARCH64_P32_TLSLD_LD_PREL19, R_AARCH64_P32_TLSDESC_LD_PREL19,
R_AARCH64_P32_TLSGD_ADR_PAGE21, R_AARCH64_P32_TLS_DTPREL,
R_AARCH64_P32_TLS_DTPMOD, R_AARCH64_P32_TLS_TPREL,
R_AARCH64_P32_TLSDESC
Fix encoding:
R_AARCH64_P32_TLSDESC_ADR_PAGE21
Reviewers: Peter Smith
Patch by: Joel Jones (jjones@cavium.com)
Differential Revision: https://reviews.llvm.org/D32072
llvm-svn: 301980
TLSDESC_ADD_LO12 relocations
Rearrange ordering in AArch64.def to follow relocation encoding
Fix name:
R_AARCH64_P32_LD64_GOT_LO12_NC => R_AARCH64_P32_LD32_GOT_LO12_NC
Add support for several "TLS", "TLSGD", and "TLSLD" relocations for
ILP32
Fix return values from isNonILP32reloc
Add implementations for
R_AARCH64_ADR_PREL_PG_HI21_NC, R_AARCH64_P32_LD32_GOT_LO12_NC,
R_AARCH64_P32_TLSIE_LD32_GOTTPREL_LO12_NC,
R_AARCH64_P32_TLSDESC_LD32_LO12, R_AARCH64_LD64_GOT_LO12_NC,
*TLSLD_LDST128_DTPREL_LO12, *TLSLD_LDST128_DTPREL_LO12_NC,
*TLSLE_LDST128_TPREL_LO12, *TLSLE_LDST128_TPREL_LO12_NC
Modify error messages to give name of equivalent relocation in the
ABI not being used, along with better checking for non-existent
requested relocations.
Added assembler support for "pg_hi21_nc"
Relocation definitions added without implementations:
R_AARCH64_P32_TLSDESC_ADR_PREL21, R_AARCH64_P32_TLSGD_ADR_PREL21,
R_AARCH64_P32_TLSGD_ADD_LO12_NC, R_AARCH64_P32_TLSLD_ADR_PREL21,
R_AARCH64_P32_TLSLD_ADR_PAGE21, R_AARCH64_P32_TLSLD_ADD_LO12_NC,
R_AARCH64_P32_TLSLD_LD_PREL19, R_AARCH64_P32_TLSDESC_LD_PREL19,
R_AARCH64_P32_TLSGD_ADR_PAGE21, R_AARCH64_P32_TLS_DTPREL,
R_AARCH64_P32_TLS_DTPMOD, R_AARCH64_P32_TLS_TPREL,
R_AARCH64_P32_TLSDESC
Fix encoding:
R_AARCH64_P32_TLSDESC_ADR_PAGE21
Reviewers: Peter Smith
Patch by: Joel Jones (jjones@cavium.com)
Differential Revision: https://reviews.llvm.org/D32072
llvm-svn: 301939
Summary:
No need to have this per-architecture. While there, unify 32-bit ARM's
behaviour with what changed elsewhere and start function names lowercase
as per the coding standards. Individual entry emission code goes to the
entry's own class.
Fully tested on amd64, cross-builds on both ARMs and PowerPC.
Reviewers: dberris
Subscribers: aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D28209
llvm-svn: 290858
This patch adds a test for the assembly code emitted with XRay
instrumentation. It also fixes a bug where the operand of a jump
instruction must be not the number of bytes to jump over, but rather the
number of 4-byte instructions.
Author: rSerge
Reviewers: dberris, rengolin
Differential Revision: https://reviews.llvm.org/D26805
llvm-svn: 287516
On CPUs with the zero cycle zeroing feature enabled "movi v.2d" should
be used to zero a vector register. This was previously done at
instruction selection time, however the register coalescer sometimes
widened multiple vregs to the Q width because of that leading to extra
spills. This patch leaves the decision on how to zero a register to the
AsmPrinter phase where it doesn't affect register allocation anymore.
This patch also sets isAsCheapAsAMove=1 on FMOVS0, FMOVD0.
This fixes http://llvm.org/PR27454, rdar://25866262
Differential Revision: http://reviews.llvm.org/D21826
llvm-svn: 274686
Of course the assembly was right but because the opcode was MOVZWi it was
encoded as "movz w16, #65535, lsl #32" which is an unallocated encoding and
would go horribly wrong on a CPU.
No idea how this bug survived this long. It seems nobody is using that aspect
of patchpoints.
llvm-svn: 272831
Finish off PR23080 by renaming the debug info IR constructs from `MD*`
to `DI*`. The last of the `DIDescriptor` classes were deleted in
r235356, and the last of the related typedefs removed in r235413, so
this has all baked for about a week.
Note: If you have out-of-tree code (like a frontend), I recommend that
you get everything compiling and tests passing with the *previous*
commit before updating to this one. It'll be easier to keep track of
what code is using the `DIDescriptor` hierarchy and what you've already
updated, and I think you're extremely unlikely to insert bugs. YMMV of
course.
Back to *this* commit: I did this using the rename-md-di-nodes.sh
upgrade script I've attached to PR23080 (both code and testcases) and
filtered through clang-format-diff.py. I edited the tests for
test/Assembler/invalid-generic-debug-node-*.ll by hand since the columns
were off-by-three. It should work on your out-of-tree testcases (and
code, if you've followed the advice in the previous paragraph).
Some of the tests are in badly named files now (e.g.,
test/Assembler/invalid-mdcompositetype-missing-tag.ll should be
'dicompositetype'); I'll come back and move the files in a follow-up
commit.
llvm-svn: 236120
Gut all the non-pointer API from the variable wrappers, except an
implicit conversion from `DIGlobalVariable` to `DIDescriptor`. Note
that if you're updating out-of-tree code, `DIVariable` wraps
`MDLocalVariable` (`MDVariable` is a common base class shared with
`MDGlobalVariable`).
llvm-svn: 234840
Before this patch code wanting to create temporary labels for a given entity
(function, cu, exception range, etc) had to keep its own counter to have stable
symbol names.
createTempSymbol would still add a suffix to make sure a new symbol was always
returned, but it kept a single counter. Because of that, if we were to use
just createTempSymbol("cu_begin"), the label could change from cu_begin42 to
cu_begin43 because some other code started using temporary labels.
Simplify this by just keeping one counter per prefix and removing the various
specialized counters.
llvm-svn: 232535
Martin Storsjo