Commit Graph

4923 Commits

Author SHA1 Message Date
Melanie Blower 931e95687d [llvm][clang][fpenv] Create new intrinsic llvm.arith.fence to control FP optimization at expression level
This intrinsic blocks floating point transformations by the optimizer.

Author: Pengfei

Reviewed By: LuoYuanke, Andy Kaylor, Craig Topper, kpn

Differential Revision: https://reviews.llvm.org/D99675
2021-06-28 12:26:52 -04:00
David Blaikie 1b112c80a6 PR37255: DebugInfo: LTO with -g inlined into -gmlt combined with Split DWARF without CU cross-references
A combination of features ^ that lead to a mismatch of expectations
about how a subprogram definition DIE would be produced with/without a
declaration when taking full -g debug info and inlining it into a -gmlt
CU - specifically when using Split DWARF that doesn't support cross-CU
references, so we have to put the -g debug info into the -gmlt CU, which
gets confusing about which mode is respected.

This patch comes down on respecting the CU the debug info is emitted
into, rather than preserving the full debug info when it's emitted into
the gmlt CU.
2021-06-27 14:40:38 -07:00
Stephen Tozer c72705678c Partial Reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands"
This is a partial reapply of the original commit and the followup commit
that were previously reverted; this reapply also includes a small fix
for a potential source of non-determinism, but also has a small change
to turn off variadic debug value salvaging, to ensure that any future
revert/reapply steps to disable and renable this feature do not risk
causing conflicts.

Differential Revision: https://reviews.llvm.org/D91722

This reverts commit 386b66b2fc.
2021-06-24 09:46:38 +01:00
zhijian bd240b3d77 [AIX][XCOFF] generate eh_info when vector registers are saved according to the traceback table.
Summary:

generate eh_info when vector registers are saved according to the traceback table.

struct eh_info_t {

unsigned version;       /* EH info version 0 */
#if defined(64BIT)

char _pad[4];           /* padding */
#endif

unsigned long lsda;     /* Pointer to Language Specific Data Area */
unsigned long personality; /* Pointer to the personality routine */
};

the value of lsda and personality is zero when the number of vector registers saved is large zero and there is not personality of the function

Reviewers: Jason Liu
Differential Revision: https://reviews.llvm.org/D103651
2021-06-22 13:01:31 -04:00
RamNalamothu 167e7afcd5 Implement DW_CFA_LLVM_* for Heterogeneous Debugging
Add support in MC/MIR for writing/parsing, and DebugInfo.

This is part of the Extensions for Heterogeneous Debugging defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html

Specifically the CFI instructions implemented here are defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html#cfa-definition-instructions

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D76877
2021-06-14 08:51:50 +05:30
Wolfgang Pieb 5a1589fc6d [static initializers] Emit global_ctors and global_dtors in reverse order when .ctors/.dtors are used.
Reviewed By: rnk, MaskRay, efriedma

Differential Revision: https://reviews.llvm.org/D103495
2021-06-10 16:44:47 -07:00
Hans Wennborg 386b66b2fc Revert "3rd Reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands""
> This reapplies c0f3dfb9, which was reverted following the discovery of
> crashes on linux kernel and chromium builds - these issues have since
> been fixed, allowing this patch to re-land.

This reverts commit 36ec97f76a.

The change caused non-determinism in the compiler, see comments on the code
review at https://reviews.llvm.org/D91722.

Reverting to unbreak people's builds until that can be addressed.

This also reverts the follow-up "[DebugInfo] Limit the number of values
that may be referenced by a dbg.value" in
a0bd6105d8.
2021-06-08 14:54:08 +02:00
Esme-Yi fbfd717197 [Debug-Info] handle DW_CC_pass_by_value/DW_CC_pass_by_reference under strict DWARF.
Summary: When -strict-dwarf=true is specified, the calling convention info
    DW_CC_pass_by_value or DW_CC_pass_by_reference can only be generated at DWARF5.

Reviewed By: shchenz, dblaikie

Differential Revision: https://reviews.llvm.org/D103300
2021-06-04 08:14:47 +00:00
Nikita Popov 983565a6fe [ADT] Move DenseMapInfo for ArrayRef/StringRef into respective headers (NFC)
This is a followup to D103422. The DenseMapInfo implementations for
ArrayRef and StringRef are moved into the ArrayRef.h and StringRef.h
headers, which means that these two headers no longer need to be
included by DenseMapInfo.h.

This required adding a few additional includes, as many files were
relying on various things pulled in by ArrayRef.h.

Differential Revision: https://reviews.llvm.org/D103491
2021-06-03 18:34:36 +02:00
Sriraman Tallam 516e5bb2b1 Resubmit D85085 after fixing the tests that were failing.
D85085 was pushed earlier but broke tests on mac and win:
http://lab.llvm.org:8080/green/job/clang-stage1-RA/21182/consoleFull#-706149783d489585b-5106-414a-ac11-3ff90657619c

Recommitting it after adding mtriple to the llc commands.

Emit correct location lists with basic block sections.

This patch addresses multiple things:

1) It ensures that const_value is emitted when possible with basic block
   sections.
2) It emits location lists such that the labels are always within the
   section boundary.
3) It fixes a bug when the parameter is first used in a non-entry block
   which is in a different section from the entry block.

Differential Revision: https://reviews.llvm.org/D85085
2021-06-01 21:59:47 -07:00
Nico Weber 192b4141f0 Revert "Emit correct location lists with basic block sections."
Breaks check-llvm on non-linux, see comments on https://reviews.llvm.org/D85085
This reverts commit caae570978
and follow-up commit 1546c52d97.
2021-05-27 11:42:04 -04:00
Sriraman Tallam caae570978 Emit correct location lists with basic block sections.
This patch addresses multiple things:

1) It ensures that const_value is emitted when possible with basic block
sections.
2) It emits location lists such that the labels are always within the
section boundary.
3) It fixes a bug when the parameter is first used in a non-entry block
which is in a different section from the entry block.

Differential Revision: https://reviews.llvm.org/D85085
2021-05-26 17:12:31 -07:00
Jeremy Morse 8496fc2ec8 [DebugInstrRef][1/3] Track PHI values through register allocation
This patch introduces "DBG_PHI" instructions, a marker of where a PHI
instruction used to be, before PHI elimination. Under the instruction
referencing model, we want to know where every value in the function is
defined -- and a PHI, even if implicit, is such a place.

Just like instruction numbers, we can use this to identify a value to be
used as a variable value, but we don't need to know what instruction
defines that value, for example:

bb1:
   DBG_PHI $rax, 1
   [... more insts ... ]
bb2:
   DBG_INSTR_REF 1, 0, !1234, !DIExpression()

This specifies that on entry to bb1, whatever value is in $rax is known
as value number one -- and the later DBG_INSTR_REF marks the position
where variable !1234 should take on value number one.

PHI locations are stored in MachineFunction for the duration of the
regalloc phase in the DebugPHIPositions map. The map is populated by
PHIElimination, and then flushed back into the instruction stream by
virtregrewriter. A small amount of maintenence is needed in
LiveDebugVariables to account for registers being split, but only for
individual positions, not for entire ranges of blocks.

Differential Revision: https://reviews.llvm.org/D86812
2021-05-26 20:24:00 +01:00
Heejin Ahn 5dd86aadf0 [WebAssembly] Add TargetInstrInfo::getCalleeOperand
DwarfDebug unconditionally assumes for all call instructions the 0th
operand is the callee operand, which seems to be true for other targets,
but not for WebAssembly. This adds `TargetInstrInfo::getCallOperand`
method whose default implementation returns `getOperand(0)` and makes
WebAssembly overrides it to use its own utility method to get the callee
operand.

This also fixes an existing bug in `WebAssembly::getCalleeOp`, which was
uncovered by this CL.

Reviewed By: dschuff, djtodoro

Differential Revision: https://reviews.llvm.org/D102978
2021-05-26 11:43:59 -07:00
Stephen Tozer 36ec97f76a 3rd Reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands"
This reapplies c0f3dfb9, which was reverted following the discovery of
crashes on linux kernel and chromium builds - these issues have since
been fixed, allowing this patch to re-land.

This reverts commit 4397b7095d.
2021-05-21 11:06:20 +01:00
Serge Pavlov c162f086ba [APFloat] convertToDouble/Float can work on shorter types
Previously APFloat::convertToDouble may be called only for APFloats that
were built using double semantics. Other semantics like single precision
were not allowed although corresponding numbers could be converted to
double without loss of precision. The similar restriction applied to
APFloat::convertToFloat.

With this change any APFloat that can be precisely represented by double
can be handled with convertToDouble. Behavior of convertToFloat was
updated similarly. It make the conversion operations more convenient and
adds support for formats like half and bfloat.

Differential Revision: https://reviews.llvm.org/D102671
2021-05-21 11:02:51 +07:00
Anirudh Prasad f076da66b9 [AsmParser][SystemZ][z/OS] Introducing HLASM Parser support to AsmParser - Part 1
- This patch (is one in a series of patches) which introduces HLASM Parser support (for the first parameter of inline asm statements) to LLVM ([[ https://lists.llvm.org/pipermail/llvm-dev/2021-January/147686.html | main RFC here ]])
- This patch in particular introduces HLASM Parser support for Z machine instructions.
- The approach taken here was to subclass `AsmParser`, and make various functions and variables as "protected" wherever appropriate.
- The `HLASMAsmParser` class overrides the `parseStatement` function. Two new private functions `parseAsHLASMLabel` and `parseAsMachineInstruction` are introduced as well.

The general syntax is laid out as follows (more information available in [[ https://www.ibm.com/support/knowledgecenter/SSENW6_1.6.0/com.ibm.hlasm.v1r6.asm/asmr1023.pdf | HLASM V1R6 Language Reference Manual ]] - Chapter 2 - Instruction Statement Format):

```
<TokA><spaces.*><TokB><spaces.*><TokC><spaces.*><TokD>
```

1. TokA is referred to as the Name Entry. This token is optional
2. TokB is referred to as the Operation Entry. This token is mandatory.
3. TokC is referred to as the Operand Entry. This token is mandatory
4. TokD is referred to as the Remarks Entry. This token is optional

- If TokA is provided, then we either parse TokA as a possible comment or as a label (Name Entry), Tok B as the Operation Entry and so on.
- If TokA is not provided (i.e. we have one or more spaces and then the first token), then we will parse the first token (i.e TokB) as a possible Z machine instruction, TokC as the operands to the Z machine instruction and TokD as a possible Remark field
- TokC (Operand Entry), no spaces are allowed between OperandEntries. If a space occurs it is classified as an error.
- TokD if provided is taken as is, and emitted as a comment.

The following additional approach was examined, but not taken:

- Adding custom private only functions to base AsmParser class, and only invoking them for z/OS. While this would eliminate the need for another child class, these private functions would be of non-use to every other target. Similarly, adding any pure virtual functions to the base MCAsmParser class and overriding them in AsmParser would also have the same disadvantage.

Testing:

- This patch doesn't have tests added with it, for the sole reason that MCStreamer Support and Object File support hasn't been added for the z/OS target (yet). Hence, it's not possible generate code outright for the z/OS target. They are in the process of being committed / process of being worked on.

- Any comments / feedback on how to combat this "lack of testing" due to other missing required features is appreciated.

Reviewed By: Kai, uweigand

Differential Revision: https://reviews.llvm.org/D98276
2021-05-19 11:05:30 -04:00
Pengxuan Zheng c9b36a041f Support GCC's -fstack-usage flag
This patch adds support for GCC's -fstack-usage flag. With this flag, a stack
usage file (i.e., .su file) is generated for each input source file. The format
of the stack usage file is also similar to what is used by GCC. For each
function defined in the source file, a line with the following information is
produced in the .su file.

<source_file>:<line_number>:<function_name> <size_in_byte> <static/dynamic>

"Static" means that the function's frame size is static and the size info is an
accurate reflection of the frame size. While "dynamic" means the function's
frame size can only be determined at run-time because the function manipulates
the stack dynamically (e.g., due to variable size objects). The size info only
reflects the size of the fixed size frame objects in this case and therefore is
not a reliable measure of the total frame size.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D100509
2021-05-15 10:22:49 -07:00
David Spickett 2db090a2eb [llvm][AsmPrinter] Restore source location to register clobber warning
Since 5de2d189e6 this particular warning
hasn't had the location of the source file containing the inline
assembly.

Fix this by reporting via LLVMContext. Which means that we no longer
have the "instantiated into assembly here" lines but they were going to
point to the start of the inline asm string anyway.

This message is already tested via IR in llvm. However we won't have
the required location info there so I've added a C file test in clang
to cover it.
(though strictly, this is testing llvm code)

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D102244
2021-05-14 08:22:57 +00:00
Chen Zheng 61484762e9 [Debug-Info] change Tag type to dwarf::Tag for createAndAddDIE; NFC
Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D102207
2021-05-13 21:15:06 -04:00
Chen Zheng 75f3beeedf [Debug-Info] make DIE attributes generation under strict DWARF control
Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D101024
2021-05-13 20:34:07 -04:00
Max Kazantsev d8b37de8a4 [GC][NFC] Move GCStrategy from CodeGen to IR
We want it to be available in analyzes so that we could use the
CodeGen notion in middle-end passes (for example, to check if
a GC may free some particular pointer).

This is a preparatory patch that simply moves the files around.

Note: if this causes some build issues, this patch must just be reverted.

Differential Revision: https://reviews.llvm.org/D100557
Reviewed By: reames
2021-05-13 12:31:59 +07:00
Fangrui Song 6a2850f3fc [AArch64][ELF] Prefer to lower MC_GlobalAddress operands to .Lfoo$local
Similar to X86 D73230 & 46788a21f9

With this change, we can set dso_local in clang's -fpic -fno-semantic-interposition mode,
for default visibility external linkage non-ifunc-non-COMDAT definitions.

For such dso_local definitions, variable access/taking the address of a
function/calling a function will go through a local alias to avoid GOT/PLT.

Note: the 'S' inline assembly constraint refers to an absolute symbolic address
or a label reference (D46745).

Differential Revision: https://reviews.llvm.org/D101872
2021-05-07 09:44:26 -07:00
Chen Zheng 9deb7eeaf7 [Debug-Info][NFC] add a wrapper for Die.addValue
Add a new wrapper function addAttribute() for Die.addValue() function,
so we can do some attributes control in one single interface.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D101125
2021-05-07 07:24:09 +00:00
RamNalamothu 41f8b8e807 [MCAsmInfo] Support UsesCFIForDebug for targets with no exception handling
This change enables emitting CFI unwind information for debugging purpose
for targets with MCAsmInfo::ExceptionsType == ExceptionHandling::None.

Currently generating CFI unwind information is entangled with supporting
the exceptions, even when AsmPrinter explicitly recognizes that the unwind
tables are being generated as debug information.

In fact, the unwind information is not generated even if we specify
--force-dwarf-frame-section, unless exceptions are enabled. The LIT test
llvm/test/CodeGen/AMDGPU/debug_frame.ll demonstrates this behavior.

Enable this option for AMDGPU to prepare for future patches which add
complete CFI support.

Reviewed By: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D78778
2021-05-06 04:53:45 +05:30
Paul Robinson 1d299252dd [DebuggerTuning] Move a comment to a more useful place.
The comment about how to make use of debugger tuning within DwarfDebug
really belongs inside the DwarfDebug declaration, where it will be
easier to find.
2021-05-03 11:08:04 -07:00
Nathan Chancellor 4397b7095d
Revert "Re-reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands""
This reverts commit 791930d740, as per
https://llvm.org/docs/DeveloperPolicy.html#patch-reversion-policy.

I observed breakage with the Linux kernel, as reported at
https://reviews.llvm.org/D91722#2724321

Fixes exist at
https://reviews.llvm.org/D101523
https://reviews.llvm.org/D101540

but they have not landed so to unbreak the tree for the weekend, revert
this commit.

Commit b11e4c9907 ("Revert "[DebugInfo] Drop DBG_VALUE_LISTs with an
excessive number of debug operands"") only reverted one follow-up fix,
not the original patch that broke the kernel.

e
2021-04-30 20:23:21 -07:00
Zequan Wu cab48e2f0e [CodeGen] don't emit addrsig symbol if it's used only by metadata
Value only used by metadata can be removed from .addrsig table.
This solves the undefined symbol error when enabling addrsig table on COFF LTO.

Differential Revision: https://reviews.llvm.org/D101512
2021-04-29 15:39:30 -07:00
jasonliu 7049fbf960 [XCOFF] Handle the case when personality routine is an alias
Summary:
Personality routine could be an alias to another personality routine.
Fix the situation when we compile the file that contains the personality
routine and the file also have functions that need to refer to the
personality routine.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D101401
2021-04-29 22:03:30 +00:00
Sriraman Tallam a64411916c Basic block sections for functions with implicit-section-name attribute
Functions can have section names set via #pragma or section attributes,
basic block sections should be correctly named for such functions.

With #pragma, the expectation is that all functions in that file are placed
in the same section in the final binary. Basic block sections should be
correctly named with the unique flag set so that the final binary has all the
basic blocks of the function in that named section. This patch fixes the bug
by calling getExplictSectionGlobal when implicit-section-name attribute is set
to make sure the function's basic blocks get the correct section name.

Differential Revision: https://reviews.llvm.org/D101311
2021-04-29 12:29:34 -07:00
RamNalamothu 63cfab4f40 [NFC] Refactor how CFI section types are represented in AsmPrinter
In terms of readability, the `enum CFIMoveType` didn't better document what it
intends to convey i.e. the type of CFI section that gets emitted.

Reviewed By: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D76519
2021-04-28 09:04:04 +05:30
Chen Zheng e5000eef81 [XCOFF] make .file directive have directory info
The .file directive is changed to only have basename in D36018 for
ELF.

But on AIX, we require the .file directive to also contain the
directory info. This aligns with other AIX compiler like XLC and is
required by some AIX tool like DBX.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D99785
2021-04-27 00:15:23 -04:00
Fangrui Song e01c666b13 Revert D76519 "[NFC] Refactor how CFI section types are represented in AsmPrinter"
This reverts commit 0ce723cb22.

D76519 was not quite NFC. If we see a CFISection::Debug function before a
CFISection::EH one (-fexceptions -fno-asynchronous-unwind-tables), we may
incorrectly pick CFISection::Debug and emit a `.cfi_sections .debug_frame`.
We should use .eh_frame instead.

This scenario is untested.
2021-04-26 15:17:28 -07:00
Jinsong Ji 2c9028170e [DebugInfo][AIX] Set target debugger-tune default to dbx
https://reviews.llvm.org/D99400 set clang DefaultDebuggerTuning for AIX
to dbx. However, we still need to update the target default so that llc
and other tools will get the same default debuggertuning, and avoid
passing extra options in LTO.

Reviewed By: #powerpc, shchenz, dblaikie

Differential Revision: https://reviews.llvm.org/D101197
2021-04-26 01:38:44 +00:00
RamNalamothu 0ce723cb22 [NFC] Refactor how CFI section types are represented in AsmPrinter
In terms of readability, the `enum CFIMoveType` didn't better document what it
intends to convey i.e. the type of CFI section that gets emitted.

Reviewed By: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D76519
2021-04-24 23:29:42 +05:30
RamNalamothu 4e87fdd786 [NFC] Delete the redundant member 'shouldEmitMoves' from DwarfCFIException class
The data member 'shouldEmitMoves' is only used in DwarfCFIException::beginFunction()
and 'shouldEmitCFI' in DwarfCFIExceptionBase serves its purpose.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101155
2021-04-24 06:35:39 +05:30
Stephen Tozer 791930d740 Re-reapply "[DebugInfo] Use variadic debug values to salvage BinOps and GEP instrs with non-const operands"
Previous build failures were caused by an error in bitcode reading and
writing for DIArgList metadata, which has been fixed in e5d844b587.
There were also some unnecessary asserts that were being triggered on
certain builds, which have been removed.

This reverts commit dad5caa59e.
2021-04-23 10:54:01 +01:00
Chen Zheng 027d6735ae [Debug-Info] change return type to void for attribute adding functions.
Make following function return void:

    addLabel()
    addSectionLabel()
    addSectionDelta()

This aligns with other attributes adding functions.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D101022
2021-04-23 04:16:55 -04:00
Michael Holman 77357208c4 [CodeView] Add CodeView support for PGO debug information
This change adds debug information about whether PGO is being used or
not.

Microsoft performance tooling (e.g. xperf, WPA) uses this information to
show whether functions are optimized with PGO or not, as well as whether
PGO information is invalid.

This information is useful for validating whether training scenarios are
providing good coverage of real world scenarios, showing if profile data
is out of date, etc.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D99994
2021-04-21 15:29:19 -07:00
Nico Weber ba7a92c01e [Support] Don't include VirtualFileSystem.h in CommandLine.h
CommandLine.h is indirectly included in ~50% of TUs when building
clang, and VirtualFileSystem.h is large.

(Already remarked by jhenderson on D70769.)

No behavior change.

Differential Revision: https://reviews.llvm.org/D100957
2021-04-21 10:19:01 -04:00
Zhang Qing Shan d69c236e1d [NFC][Debug] Fix unnecessary deep-copy for vector to save compiling time
We saw some big compiling time impact after enabling the debug entry value
feature for X86 platform(D73534). Compiling time goes from 900s->1600s with
our testcase. It is caused by allocating/freeing the memory busily.

'using FwdRegWorklist = MapVector<unsigned, SmallVector<FwdRegParamInfo, 2>>;'
The value for this map is vector, and we miss the reference when access the
element. The same happens for `auto CalleesMap = MF->getCallSitesInfo();` which is a DenseMap.

Reviewed by: djtodoro, flychen50

Differential Revision: https://reviews.llvm.org/D100162
2021-04-12 14:55:03 +08:00
Chen Zheng bb346146a5 [Debug-Info] make fortran CHARACTER(1) type as valid unsigned type
This resolves https://bugs.llvm.org/show_bug.cgi?id=49872

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D100015
2021-04-11 23:17:01 -04:00
Esme-Yi 0c36da722a [Debug-Info] Use inlined strings in .dwinfo section by default for DBX.
Summary: Set the default DwarfInlinedStrings as inlined strings for DBX, due to DBX does not support .dwstr section for now.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D99933
2021-04-08 07:20:22 +00:00
Arthur Eubanks 90af134473 Revert "[AsmPrinter] Delete dead takeDeletedSymbsForFunction()"
This reverts commit 9583a3f262.

This wasn't NFC as initially thought. Needed for D99707.
2021-04-07 11:40:44 -07:00
Sourabh Singh Tomar f13f050551 [DebugInfo] Support for signed constants inside DIExpression
Negative numbers are represented using DW_OP_consts along with signed representation
of the number as the argument.

Test case IR is generated using Fortran front-end.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D99273
2021-03-30 23:20:38 +05:30
Tomas Matheson a9968c0a33 [NFC][CodeGen] Tidy up TargetRegisterInfo stack realignment functions
Currently needsStackRealignment returns false if canRealignStack returns false.
This means that the behavior of needsStackRealignment does not correspond to
it's name and description; a function might need stack realignment, but if it
is not possible then this function returns false. Furthermore,
needsStackRealignment is not virtual and therefore some backends have made use
of canRealignStack to indicate whether a function needs stack realignment.

This patch attempts to clarify the situation by separating them and introducing
new names:

 - shouldRealignStack - true if there is any reason the stack should be
   realigned

 - canRealignStack - true if we are still able to realign the stack (e.g. we
   can still reserve/have reserved a frame pointer)

 - hasStackRealignment = shouldRealignStack && canRealignStack (not target
   customisable)

Targets can now override shouldRealignStack to indicate that stack realignment
is required.

This change will make it easier in a future change to handle the case where we
need to realign the stack but can't do so (for example when the register
allocator creates an aligned spill after the frame pointer has been
eliminated).

Differential Revision: https://reviews.llvm.org/D98716

Change-Id: Ib9a4d21728bf9d08a545b4365418d3ffe1af4d87
2021-03-30 17:31:39 +01:00
Alok Kumar Sharma 9fb0025f70 [DebugInfo] Upgrade DISubragne::count to accept DIExpression also
This is needed for Fortran assumed shape arrays whose dimensions are
defined as,
  - 'count' is taken from array descriptor passed as parameter by
    caller, access from descriptor is defined by type DIExpression.
  - 'lowerBound' is defined by callee.
The current alternate way represents using upperBound in place of
count, where upperBound is calculated in callee in a temp variable
using lowerBound and count

Representation with count (DIExpression) is not only clearer as
compared to upperBound (DIVariable) but it has another advantage that
variable count is accessed by being parameter has better chance of
survival at higher optimization level than upperBound being local
variable.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D99335
2021-03-30 09:16:55 +05:30
Rahman Lavaee 90c401cab6 [Propeller] Do not generate the BB address map for empty functions.
Empty functions (functions with no real code) are irrelevant for propeller optimizations and their addresses sometimes conflict with other functions which obfuscates the analysis.
This simple change skips the BB address map emission for such functions.

Reviewed By: tmsriram

Differential Revision: https://reviews.llvm.org/D99395
2021-03-29 20:15:01 -07:00
Rahman Lavaee 949abf7d6a [llvm-readelf, propeller] Add fallthrough bit to basic block metadata in BB-Address-Map section.
This patch adds a fallthrough bit to basic block metadata, indicating whether the basic block can fallthrough without taking any branches. The bit will help us avoid an intel LBR bug which results in occasional duplicate entries at the beginning of the LBR stack.

This patch uses `MachineBasicBlock::canFallThrough()` to set the bit. This is not a const method because it eventually calls `TargetInstrInfo::analyzeBranch`, but it calls this function with the default `AllowModify=false`. So we can either make the argument to the `getBBAddrMapMetadata` non-const, or we can use `const_cast` when calling `canFallThrough`. I decide to go with the latter since this is purely due to legacy code, and in general we should not allow the BasicBlock to be mutable during `getBBAddrMapMetadata`.

Reviewed By: tmsriram

Differential Revision: https://reviews.llvm.org/D96918
2021-03-22 21:38:05 -07:00
Fangrui Song 5d44c92bf8 Change void getNoop(MCInst &NopInst) to MCInst getNop()
Prefer (self-documenting) return values to output parameters (which are
liable to be used).
While here, rename Noop to Nop which is more widely used and improves
consistency with hasEmitNops/setEmitNops/emitNop/etc.
2021-03-15 12:05:34 -07:00