Follow the X86 and Mips renaming.
> "Relocation modifier" suggests adjustments happen during the linker's relocation step rather than the assembler's expression evaluation.
> "Relocation specifier" is clear, aligns with Arm and IBM’s usage, and fits the assembler's role seamlessly.
In addition, rename *MCExpr::getKind, which confusingly shadows the base class getKind.
Most changes are mechanic, except:
* ELFObjectWriter::shouldRelocateWithSymbol: .TOC.@tocbase does not
register the undefined symbol. Move the handling into the
Sym->isUndefined() code path.
* ELFObjectWriter::fixSymbolsInTLSFixups's VK_PPC* cases are moved to
PPCELFObjectWriter::getRelocType. We should do similar refactoring
for other targets and eventually remove fixSymbolsInTLSFixups.
In the future, we should classify PPCMCExpr similar to AArch64MCExpr.
Make the name conciser. PPC-specific MCSymbolRefExpr::VariantKind
members will be moved to PPCMCExpr and we will not ue
MCSymbolRefExpr::VariantKind's "generic" members, so there won't be
mix-and-match.
This cleans up @l @ha optimization in PPCAsmParser and is also the first
step toward removing VK_PPC_* from the generic MCSymbolRefExpr::VariantKind.
Basically we ensure that @l @ha family modifiers always lead to
PPCMCExpr and avoid MCSymbolRefExpr::VariantKind. This allows us
to delete a lot of switch statements that involve a long list of VK_PPC_LO/VK_PPC_HI/...
52cf8e44880bcf614068b66b63393aa8da1edd76 (2013) introduced the
VK_PPC_TLSGD workaround to prevent unconditional reference to
_GLOBAL_OFFSET_TABLE_ in ELFObjectWriter.
e2b355d651ed8f2cbe61672c4c39b6419e471265 (2015) removed the
`_GLOBAL_OFFSET_TABLE_` hack for the generic VK_TLSGD,
making the VK_PPC_TLSGD workaround unneeded.
https://reviews.llvm.org/D95518 used switchSectionNoPrint,
which seems buggy as .ll -> .s -> .o will be different from
.ll -> .o, but this change intends to be a NFC.
AIX assembly is very different from the gas syntax. We don't expect
other targets to share these differences. Unify the numerous,
essentially AIX-specific variables.
This PR registers the writeout and reset functions for `gcov` for all
modules in the PGO runtime, instead of registering them
using global constructors in each module. The change is made for AIX
only, but the same mechanism works on Linux on Power.
When registering such functions using global constructors in each module
without `-ffunction-sections`, the AIX linker cannot garbage collect
unused undefined symbols, because such symbols are grouped in the same
section as the `__sinit` symbol. Keeping such undefined symbols causes
link errors (see test case
https://github.com/llvm/llvm-project/pull/108570/files#diff-500a7e1ba871e1b6b61b523700d5e30987900002add306e1b5e4972cf6d5a4f1R1
for this scenario). This PR implements the initialization in the
runtime, hence avoiding introducing `__sinit` into each module.
The implementation adds a new global variable `__llvm_covinit_functions`
to each module. This new global variable contains the function pointers
to the `Writeout` and `Reset` functions. `__llvm_covinit_functions`'s
section is the named section `__llvm_covinit`. The linker will aggregate
all the `__llvm_covinit` sections from each module
to form one single named section in the final binary. The pair of
functions
```
const __llvm_gcov_init_func_struct *__llvm_profile_begin_covinit();
const __llvm_gcov_init_func_struct *__llvm_profile_end_covinit();
```
are implemented to return the start and end address of this named
section in the final binary, and they are used in function
```
__llvm_profile_gcov_initialize()
```
(which is a constructor function in the runtime) so the runtime knows
the addresses of all the `Writeout` and `Reset` functions from all the
modules.
One noticeable implementation detail relevant to AIX is that to preserve
the `__llvm_covinit` from the linker's garbage collection, a `.ref`
pseudo instruction is inserted into them, referring to the section that
contains the `__llvm_gcov_ctr` variables, which are used in the
instrumented code. The `__llvm_gcov_ctr` variables did not belong to
named sections before, but this PR added them to the
`__llvm_gcov_ctr_section` named section, so we can add a `.ref` pseudo
instruction that refers to them in the `__llvm_covinit` section.
Don't call raw_string_ostream::flush(), which is essentially a no-op.
As specified in the docs, raw_string_ostream is always unbuffered.
( 65b13610a5226b84889b923bae884ba395ad084d for further reference )
This avoids another unserializable field. Move the DbgInfoAvailable
field into the AsmPrinter, which is only really a cache/convenience
bit for checking a direct IR module metadata check.
For now only PPC big endian Linux 32 and 64 bit are supported.
PPC little endian Linux has XRAY support for 64-bit.
PPC AIX has different patchable function entry implementations.
Fixes#63220Fixes#57031
This patch adds support for toc-data for 64-bit large code-model on AIX.
The sequence ADDIStocHA8/ADDItocL8 is used to access the data directly
from the TOC.
When emitting the instruction ADDIStocHA8, we check if the symbol has
toc-data attribute before creating a toc entry for it. When emitting the
instruction ADDItocL8, we use the LA8 instruction to load the address.
Under some circumstance (library loaded with the main program), TLS
initial-exec model can be applied to local-dynamic access(es). We
could use some simple heuristic to decide the update at function level:
* If there is equal or less than a number of TLS local-dynamic access(es)
in the function, use TLS initial-exec model. (the threshold which default to
1 is controlled by hidden option)
I'm planning to remove StringRef::equals in favor of
StringRef::operator==.
- StringRef::operator==/!= outnumber StringRef::equals by a factor of
38 under llvm/ in terms of their usage.
- The elimination of StringRef::equals brings StringRef closer to
std::string_view, which has operator== but not equals.
- S == "foo" is more readable than S.equals("foo"), especially for
!Long.Expression.equals("str") vs Long.Expression != "str".
Following the aix-small-local-exec-tls target attribute, this patch adds
a target attribute for an AIX-specific option in llc that informs the
compiler that it can use a faster access sequence for the local-dynamic
TLS model (formally named aix-small-local-dynamic-tls) when TLS
variables are less than ~32KB in size.
The patch either produces an addi/la with a displacement off of module
handle (return value from .__tls_get_mod) when the address is
calculated, or it produces an addi/la followed by a load/store when the
address is calculated and used for further accesses.
---------
Co-authored-by: Amy Kwan <amy.kwan1@ibm.com>
Exploit the per global code model attribute on AIX. On AIX we need to
update both the code sequence used to access the global (either 1 or 2
instructions for small and large code model respectively) and the
storage mapping class that we emit the toc entry.
---------
Co-authored-by: Amy Kwan <akwan0907@gmail.com>
The following tests fail when built with Address
and Undefined sanitizers:
CodeGen/PowerPC/basic-toc-data-def.ll
CodeGen/PowerPC/toc-data-large-array2.ll
Subtarget may be null in emitGlobalVariable, for example in the testcase
where we have no functions in the IR. The fix moves this function from
PPCSubtarget to a static helper function. This only fails with
sanitizers because the Subtarget is not used in the member function.
In preparation of adding a similar instruction for large code model on
AIX for 32-bit, rename the exisitng ADDItocL 64-instruction to ADDItocL8
to match the naming convention of other instructions with 32-bit and
64-bit variants.
Without this gcc warns like
../lib/Target/PowerPC/PPCAsmPrinter.cpp:1650:33: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
1650 | (InstDisp >= -32768) &&
| ~~~~~~~~~~~~~~~~~~~~~^~
1651 | "Expecting the instruction displacement for local-exec TLS "
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1652 | "variables to be between [-32768, 32768)!");
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This patch utilizes the -maix-small-local-exec-tls option to produce a
faster,
non-TOC-based access sequence for the local-exec TLS model.
Specifically, for
when the offsets from the TLS variable are non-zero.
In particular, this patch produces either a single:
- addi/la with a displacement off of R13 plus a non-zero offset for when
an address is calculated, or
- load or store off of R13 plus a non-zero offset for when an address is
calculated and used for further
access where R13 is the thread pointer, respectively.
In order to produce a single addi or load/store off of the thread
pointer with a non-zero offset,
this patch also adds the necessary support in the assembly printer when
printing these instructions.
Specifically:
- The non-zero offset is added to the TLS variable address when the
address of the
TLS variable + it's offset is less than 32KB.
- Otherwise, when the address of the TLS variable + its offset is
greater than 32KB, the
non-zero offset (and a multiple of 64KB) is subtracted from the TLS
address.
This handling in the assembly printer is necessary to ensure that the
TLS address + the non-zero offset
is between [-32768, 32768), so that the total displacement can fit
within the addi/load/store instructions.
This patch is meant to be a follow-up to
3f46e5453d9310b15d974e876f6132e3cf50c4b1 (where the
optimization occurs for when the offset is zero).
This patch adds support for common and local symbols in the TOC for AIX.
Note that we need to update isVirtualSection so as a common symbol in
TOC will have the symbol type XTY_CM and will be initialized when placed
in the TOC so sections with this type are no longer virtual.
---------
Co-authored-by: Zaara Syeda <syzaara@ca.ibm.com>
Make __builtin_cpu_{init|supports|is} target independent and provide an
opt-in query for targets that want to support it. Each target is still
responsible for their specific lowering/code-gen. Also provide code-gen
for PowerPC.
I originally proposed this in https://reviews.llvm.org/D152914 and this
addresses the comments I received there.
---------
Co-authored-by: Nemanja Ivanovic <nemanjaivanovic@nemanjas-air.kpn>
Co-authored-by: Nemanja Ivanovic <nemanja@synopsys.com>
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
12 bit is not enough for PPC's target specific flags. If 8 bit for the
bitmask flags, 4 bit for the direct mask, PPC can total have 16 direct
mask and 8 bitmask. Not enough for PPC, see this issue in
https://github.com/llvm/llvm-project/pull/66316
Redesign how PPC target set the target specific flags. With this patch,
all ppc target flags are direct flags. No bitmask flag in PPC anymore.
This patch aligns with some targets like X86 which also has many target
specific flags.
The patch also fixes a bug related to flag `MO_TLSGDM_FLAG` and `MO_LO`.
They are the same value and the test case changes in this PR shows the
bug.
This patch utilizes the -maix-small-local-exec-tls option added in
D155544 to produce a faster access sequence for the local-exec TLS
model, where loading from the TOC can be avoided.
The patch either produces an addi/la with a displacement off of r13
(the thread pointer) when the address is calculated, or it produces an
addi/la followed by a load/store when the address is calculated and
used for further accesses.
This patch also optimizes this sequence a bit more where we can remove
the addi/la when the load/store offset is 0. A follow up patch will
be posted to account for when the load/store offset is non-zero, and
currently in these situations we keep the addi/la that precedes the
load/store.
Furthermore, this access sequence is only performed for TLS variables
that are less than ~32KB in size.
Differential Revision: https://reviews.llvm.org/D155600
/Users/jiefu/llvm-project/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp:2753:34: error: cannot initialize a parameter of type 'int64_t' (aka 'long long') with an rvalue of type 'thread::id' (aka '_opaque_pthread_t *')
"_" + llvm::itostr(llvm::this_thread::get_id()) + "_" +
^~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/jiefu/llvm-project/llvm/include/llvm/ADT/StringExtras.h:315:35: note: passing argument to parameter 'X' here
inline std::string itostr(int64_t X) {
^
1 error generated.
With ThinLTO, when compiling SPEC 2017 omnetpp_r with -threads=4, two
small modules can end up with the same timestamp in their sinit symbols
when calculating time in seconds, creating duplicate definitions.
This patch uses a timestamp in nanoseconds.
Because the race can be between threads, embed the thread ID as well.
Reviewed By: xingxue, daltenty
Differential Revision: https://reviews.llvm.org/D159319
