Commit Graph

816 Commits

Author SHA1 Message Date
Rafael Espindola a869576008 Create a MCSymbolELF.
This create a MCSymbolELF class and moves SymbolSize since only ELF
needs a size expression.

This reduces the size of MCSymbol from 56 to 48 bytes.

llvm-svn: 238801
2015-06-02 00:25:12 +00:00
Matt Arsenault bd7d80a4a6 Add address space argument to isLegalAddressingMode
This is important because of different addressing modes
depending on the address space for GPU targets.

This only adds the argument, and does not update
any of the uses to provide the correct address space.

llvm-svn: 238723
2015-06-01 05:31:59 +00:00
Jim Grosbach 13760bd152 MC: Clean up MCExpr naming. NFC.
llvm-svn: 238634
2015-05-30 01:25:56 +00:00
Rafael Espindola 0709a7bd1a Move alignment from MCSectionData to MCSection.
This starts merging MCSection and MCSectionData.

There are a few issues with the current split between MCSection and
MCSectionData.

* It optimizes the the not as important case. We want the production
of .o files to be really fast, but the split puts the information used
for .o emission in a separate data structure.

* The ELF/COFF/MachO hierarchy is not represented in MCSectionData,
leading to some ad-hoc ways to represent the various flags.

* It makes it harder to remember where each item is.

The attached patch starts merging the two by moving the alignment from
MCSectionData to MCSection.

Most of the patch is actually just dropping 'const', since
MCSectionData is mutable, but MCSection was not.

llvm-svn: 237936
2015-05-21 19:20:38 +00:00
David Blaikie ff6409d096 Simplify IRBuilder::CreateCall* by using ArrayRef+initializer_list/braced init only
llvm-svn: 237624
2015-05-18 22:13:54 +00:00
Jim Grosbach 6f482000e9 MC: Clean up method names in MCContext.
The naming was a mish-mash of old and new style. Update to be consistent
with the new. NFC.

llvm-svn: 237594
2015-05-18 18:43:14 +00:00
Jim Grosbach 4c98cf77d9 MC: MCCodeGenInfo naming update. NFC.
s/InitMCCodeGenInfo/initMCCodeGenInfo/

llvm-svn: 237471
2015-05-15 19:13:31 +00:00
Daniel Sanders 734400b46a [xcore] Only support the 'm' inline assembly memory constraint. NFC.
Summary:
XCore doesn't seem to have any additional constraints. Therefore remove
the target hook.

No functional change intended.

Reviewers: friedgold

Reviewed By: friedgold

Subscribers: friedgold, llvm-commits

Differential Revision: http://reviews.llvm.org/D8921

llvm-svn: 237442
2015-05-15 12:32:16 +00:00
Jim Grosbach e9119e41ef MC: Modernize MCOperand API naming. NFC.
MCOperand::Create*() methods renamed to MCOperand::create*().

llvm-svn: 237275
2015-05-13 18:37:00 +00:00
Douglas Katzman 03dfca04df Strip trailing whitespace. NFC
llvm-svn: 237165
2015-05-12 19:42:31 +00:00
Matthias Braun d04893fa36 Change getTargetNodeName() to produce compiler warnings for missing cases, fix them
llvm-svn: 236775
2015-05-07 21:33:59 +00:00
Quentin Colombet 61b305edfd [ShrinkWrap] Add (a simplified version) of shrink-wrapping.
This patch introduces a new pass that computes the safe point to insert the
prologue and epilogue of the function.
The interest is to find safe points that are cheaper than the entry and exits
blocks.

As an example and to avoid regressions to be introduce, this patch also
implements the required bits to enable the shrink-wrapping pass for AArch64.


** Context **

Currently we insert the prologue and epilogue of the method/function in the
entry and exits blocks. Although this is correct, we can do a better job when
those are not immediately required and insert them at less frequently executed
places.
The job of the shrink-wrapping pass is to identify such places.


** Motivating example **

Let us consider the following function that perform a call only in one branch of
a if:
define i32 @f(i32 %a, i32 %b)  {
 %tmp = alloca i32, align 4
 %tmp2 = icmp slt i32 %a, %b
 br i1 %tmp2, label %true, label %false

true:
 store i32 %a, i32* %tmp, align 4
 %tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
 br label %false

false:
 %tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
 ret i32 %tmp.0
}

On AArch64 this code generates (removing the cfi directives to ease
readabilities):
_f:                                     ; @f
; BB#0:
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
LBB0_2:                                 ; %false
  mov  sp, x29
  ldp x29, x30, [sp], #16
  ret

With shrink-wrapping we could generate:
_f:                                     ; @f
; BB#0:
  cmp  w0, w1
  b.ge  LBB0_2
; BB#1:                                 ; %true
  stp x29, x30, [sp, #-16]!
  mov  x29, sp
  sub sp, sp, #16             ; =16
  stur  w0, [x29, #-4]
  sub x1, x29, #4             ; =4
  mov  w0, wzr
  bl  _doSomething
  add sp, x29, #16            ; =16
  ldp x29, x30, [sp], #16
LBB0_2:                                 ; %false
  ret

Therefore, we would pay the overhead of setting up/destroying the frame only if
we actually do the call.


** Proposed Solution **

This patch introduces a new machine pass that perform the shrink-wrapping
analysis (See the comments at the beginning of ShrinkWrap.cpp for more details).
It then stores the safe save and restore point into the MachineFrameInfo
attached to the MachineFunction.
This information is then used by the PrologEpilogInserter (PEI) to place the
related code at the right place. This pass runs right before the PEI.

Unlike the original paper of Chow from PLDI’88, this implementation of
shrink-wrapping does not use expensive data-flow analysis and does not need hack
to properly avoid frequently executed point. Instead, it relies on dominance and
loop properties.

The pass is off by default and each target can opt-in by setting the
EnableShrinkWrap boolean to true in their derived class of TargetPassConfig.
This setting can also be overwritten on the command line by using
-enable-shrink-wrap.

Before you try out the pass for your target, make sure you properly fix your
emitProlog/emitEpilog/adjustForXXX method to cope with basic blocks that are not
necessarily the entry block.


** Design Decisions **

1. ShrinkWrap is its own pass right now. It could frankly be merged into PEI but
for debugging and clarity I thought it was best to have its own file.
2. Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point, the impacted
component would then be:
- The pass itself: New algorithm needed.
- MachineFrameInfo: Hold a list or set of Save/Restore point instead of one
  pointer.
- PEI: Should loop over the save point and restore point.
Anyhow, at least for this first iteration, I do not believe this is interesting
to support the complex cases. We should revisit that when we motivating
examples.

Differential Revision: http://reviews.llvm.org/D9210

<rdar://problem/3201744>

llvm-svn: 236507
2015-05-05 17:38:16 +00:00
Sergey Dmitrouk 842a51bad8 Reapply r235977 "[DebugInfo] Add debug locations to constant SD nodes"
[DebugInfo] Add debug locations to constant SD nodes

This adds debug location to constant nodes of Selection DAG and updates
all places that create constants to pass debug locations
(see PR13269).

Can't guarantee that all locations are correct, but in a lot of cases choice
is obvious, so most of them should be. At least all tests pass.

Tests for these changes do not cover everything, instead just check it for
SDNodes, ARM and AArch64 where it's easy to get incorrect locations on
constants.

This is not complete fix as FastISel contains workaround for wrong debug
locations, which drops locations from instructions on processing constants,
but there isn't currently a way to use debug locations from constants there
as llvm::Constant doesn't cache it (yet). Although this is a bit different
issue, not directly related to these changes.

Differential Revision: http://reviews.llvm.org/D9084

llvm-svn: 235989
2015-04-28 14:05:47 +00:00
Daniel Jasper 48e93f7181 Revert "[DebugInfo] Add debug locations to constant SD nodes"
This breaks a test:
http://bb.pgr.jp/builders/cmake-llvm-x86_64-linux/builds/23870

llvm-svn: 235987
2015-04-28 13:38:35 +00:00
Sergey Dmitrouk adb4c69d5c [DebugInfo] Add debug locations to constant SD nodes
This adds debug location to constant nodes of Selection DAG and updates
all places that create constants to pass debug locations
(see PR13269).

Can't guarantee that all locations are correct, but in a lot of cases choice
is obvious, so most of them should be. At least all tests pass.

Tests for these changes do not cover everything, instead just check it for
SDNodes, ARM and AArch64 where it's easy to get incorrect locations on
constants.

This is not complete fix as FastISel contains workaround for wrong debug
locations, which drops locations from instructions on processing constants,
but there isn't currently a way to use debug locations from constants there
as llvm::Constant doesn't cache it (yet). Although this is a bit different
issue, not directly related to these changes.

Differential Revision: http://reviews.llvm.org/D9084

llvm-svn: 235977
2015-04-28 11:56:37 +00:00
Lang Hames 9ff69c8f4d [AsmPrinter] Make AsmPrinter's OutStreamer member a unique_ptr.
AsmPrinter owns the OutStreamer, so an owning pointer makes sense here. Using a
reference for this is crufty.

llvm-svn: 235752
2015-04-24 19:11:51 +00:00
Krzysztof Parzyszek a46c36b8f4 Allow memory intrinsics to be tail calls
llvm-svn: 234764
2015-04-13 17:16:45 +00:00
Alexander Kornienko f817c1cb9a Use 'override/final' instead of 'virtual' for overridden methods
The patch is generated using clang-tidy misc-use-override check.

This command was used:

  tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py \
    -checks='-*,misc-use-override' -header-filter='llvm|clang' \
    -j=32 -fix -format

http://reviews.llvm.org/D8925

llvm-svn: 234679
2015-04-11 02:11:45 +00:00
David Blaikie aa41cd57e0 [opaque pointer type] More GEP IRBuilder API migrations...
llvm-svn: 234058
2015-04-03 21:33:42 +00:00
David Blaikie 4a2e73b066 [opaque pointer type] API migration for GEP constant factories
Require the pointee type to be passed explicitly and assert that it is
correct. For now it's possible to pass nullptr here (and I've done so in
a few places in this patch) but eventually that will be disallowed once
all clients have been updated or removed. It'll be a long road to get
all the way there... but if you have the cahnce to update your callers
to pass the type explicitly without depending on a pointer's element
type, that would be a good thing to do soon and a necessary thing to do
eventually.

llvm-svn: 233938
2015-04-02 18:55:32 +00:00
Eric Christopher f8019408dc Replace the MCSubtargetInfo parameter with a Triple when creating
an MCInstPrinter. Update all callers and use where we wanted a Triple
previously.

llvm-svn: 233648
2015-03-31 00:10:04 +00:00
Eric Christopher c7c5592b7e Remove unused Target argument from MCInstPrinter ctor functions.
llvm-svn: 233607
2015-03-30 21:52:21 +00:00
Akira Hatanaka b46d0234a6 [MCInstPrinter] Enable MCInstPrinter to change its behavior based on the
per-function subtarget.

Currently, code-gen passes the default or generic subtarget to the constructors
of MCInstPrinter subclasses (see LLVMTargetMachine::addPassesToEmitFile), which
enables some targets (AArch64, ARM, and X86) to change their instprinter's
behavior based on the subtarget feature bits. Since the backend can now use
different subtargets for each function, instprinter has to be changed to use the
per-function subtarget rather than the default subtarget.

This patch takes the first step towards enabling instprinter to change its
behavior based on the per-function subtarget. It adds a bit "PassSubtarget" to
AsmWriter which tells table-gen to pass a reference to MCSubtargetInfo to the
various print methods table-gen auto-generates. 

I will follow up with changes to instprinters of AArch64, ARM, and X86.

llvm-svn: 233411
2015-03-27 20:36:02 +00:00
Eric Christopher 4d0f35a901 Remove the target independent TargetMachine::getSubtarget and
TargetMachine::getSubtargetImpl routines.

This keeps the target independent code free of bare subtarget
calls while the remainder of the backends are migrated, or not
if they don't wish to support per-function subtargets as would
be needed for function multiversioning or LTO of disparate
cpu subarchitecture types, e.g.

clang -msse4.2 -c foo.c -emit-llvm -o foo.bc
clang -c bar.c -emit-llvm -o bar.bc
llvm-link foo.bc bar.bc -o baz.bc
llc baz.bc

and get appropriate code for what the command lines requested.

llvm-svn: 232885
2015-03-21 04:22:23 +00:00
Rafael Espindola 73870dd438 There is only one Asm streamer, there is no need for targets to register it.
Instead, have the targets register a TargetStreamer to be use with the
asm streamer (if any).

llvm-svn: 232423
2015-03-16 21:43:42 +00:00
Daniel Sanders bf5b80f5f9 Make each target map all inline assembly memory constraints to InlineAsm::Constraint_m. NFC.
Summary:
This is instead of doing this in target independent code and is the last
non-functional change before targets begin to distinguish between
different memory constraints when selecting code for the ISD::INLINEASM
node.

Next, each target will individually move away from the idea that all
memory constraints behave like 'm'.

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8173

llvm-svn: 232373
2015-03-16 13:13:41 +00:00
Daniel Sanders 60f1db0525 Recommit r232027 with PR22883 fixed: Add infrastructure for support of multiple memory constraints.
The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break
anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate
Constraint_* values.

PR22883 was caused the matching operands copying the whole of the operand flags
for the matched operand. This included the constraint id which needed to be
replaced with the operand number. This has been fixed with a conversion
function. Following on from this, matching operands also used the operand
number as the constraint id. This has been fixed by looking up the matched
operand and taking it from there. 

llvm-svn: 232165
2015-03-13 12:45:09 +00:00
Hal Finkel e78e52ba9b Revert "r232027 - Add infrastructure for support of multiple memory constraints"
This (r232027) has caused PR22883; so it seems those bits might be used by
something else after all. Reverting until we can figure out what else to do.

Original commit message:

The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate Constraint_*
values.

llvm-svn: 232093
2015-03-12 20:09:39 +00:00
Daniel Sanders 41c072e63b Add infrastructure for support of multiple memory constraints.
Summary:
The operand flag word for ISD::INLINEASM nodes now contains a 15-bit
memory constraint ID when the operand kind is Kind_Mem. This constraint
ID is a numeric equivalent to the constraint code string and is converted
with a target specific hook in TargetLowering.

This patch maps all memory constraints to InlineAsm::Constraint_m so there
is no functional change at this point. It just proves that using these
previously unused bits in the encoding of the flag word doesn't break anything.

The next patch will make each target preserve the current mapping of
everything to Constraint_m for itself while changing the target independent
implementation of the hook to return Constraint_Unknown appropriately. Each
target will then be adapted in separate patches to use appropriate Constraint_*
values.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8171

llvm-svn: 232027
2015-03-12 11:00:48 +00:00
Mehdi Amini 93e1ea167e Move the DataLayout to the generic TargetMachine, making it mandatory.
Summary:
I don't know why every singled backend had to redeclare its own DataLayout.
There was a virtual getDataLayout() on the common base TargetMachine, the
default implementation returned nullptr. It was not clear from this that
we could assume at call site that a DataLayout will be available with
each Target.

Now getDataLayout() is no longer virtual and return a pointer to the
DataLayout member of the common base TargetMachine. I plan to turn it into
a reference in a future patch.

The only backend that didn't have a DataLayout previsouly was the CPPBackend.
It now initializes the default DataLayout. This commit is NFC for all the
other backends.

Test Plan: clang+llvm ninja check-all

Reviewers: echristo

Subscribers: jfb, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8243

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231987
2015-03-12 00:07:24 +00:00
Eric Christopher 7af9528747 Have getCalleeSavedRegs take a non-null MachineFunction all the
time. The target independent code was passing in one all the
time and targets weren't checking validity before using. Update
a few calls to pass in a MachineFunction where necessary.

llvm-svn: 231970
2015-03-11 21:41:28 +00:00
Reid Kleckner 294fa7aa9d TableGen: Use 'enum : uint64_t' for feature flags to fix -Wmicrosoft
clang-cl would warn that this value is not representable in 'int':
  enum { FeatureX = 1ULL << 31 };
All MS enums are 'ints' unless otherwise specified, so we have to use an
explicit type.  The AMDGPU target just hit 32 features, triggering this
warning.

Now that we have C++11 strong enum types, we can also eliminate the
'const uint64_t' codepath from tablegen and just use 'enum : uint64_t'.

llvm-svn: 231697
2015-03-09 20:23:14 +00:00
Eric Christopher 11e4df73c8 getRegForInlineAsmConstraint wants to use TargetRegisterInfo for
a lookup, pass that in rather than use a naked call to getSubtargetImpl.
This involved passing down and around either a TargetMachine or
TargetRegisterInfo. Update all callers/definitions around the targets
and SelectionDAG.

llvm-svn: 230699
2015-02-26 22:38:43 +00:00
Eric Christopher 23a3a7c871 Remove an argument-less call to getSubtargetImpl from TargetLoweringBase.
This required plumbing a TargetRegisterInfo through computeRegisterProperties
and into findRepresentativeClass which uses it for register class
iteration. This required passing a subtarget into a few target specific
initializations of TargetLowering.

llvm-svn: 230583
2015-02-26 00:00:24 +00:00
Tim Northover 3b6b7ca2bc CodeGen: convert CCState interface to using ArrayRefs
Everyone except R600 was manually passing the length of a static array
at each callsite, calculated in a variety of interesting ways. Far
easier to let ArrayRef handle that.

There should be no functional change, but out of tree targets may have
to tweak their calls as with these examples.

llvm-svn: 230118
2015-02-21 02:11:17 +00:00
Chandler Carruth 30d69c2e36 [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00
Eric Christopher 8341358adc Since TargetLowering is already subtarget dependent just pass
in the subtarget and stash it in the class so that lookups are
easier and safer.

llvm-svn: 227819
2015-02-02 17:52:27 +00:00
Eric Christopher 1c50429923 Use the function template getSubtarget on the MachineFunction
rather than a larger explicit cast.

llvm-svn: 227818
2015-02-02 17:52:25 +00:00
Eric Christopher 40fb765888 Remove unused class variable.
llvm-svn: 227817
2015-02-02 17:52:23 +00:00
Eric Christopher 49a0fd7444 Remove unused class variable.
llvm-svn: 227816
2015-02-02 17:52:20 +00:00
Chandler Carruth c956ab6603 [multiversion] Switch the TTI queries from TargetMachine to Subtarget
now that we have a correct and cached subtarget specific to the
function.

Also, finish providing a cached per-function subtarget in the core
LLVMTargetMachine -- that layer hadn't switched over yet.

The only use of the TargetMachine was to re-lookup a subtarget for
a particular function to work around the fact that TTI was immutable.
Now that it is per-function and we haved a cached subtarget, use it.

This still leaves a few interfaces with real warts on them where we were
passing Function objects through the TTI interface. I'll remove these
and clean their usage up in subsequent commits now that this isn't
necessary.

llvm-svn: 227738
2015-02-01 14:22:17 +00:00
Chandler Carruth c340ca839c [multiversion] Remove the cached TargetMachine pointer from the
intermediate TTI implementation template and instead query up to the
derived class for both the TargetMachine and the TargetLowering.

Most of the derived types had a TLI cached already and there is no need
to store a less precisely typed target machine pointer.

This will in turn make it much cleaner to look up the TLI via
a per-function subtarget instead of the generic subtarget, and it will
pave the way toward pulling the subtarget used for unroll preferences
into the same form once we are *always* using the function to look up
the correct subtarget.

llvm-svn: 227737
2015-02-01 14:01:15 +00:00
Chandler Carruth 8b04c0d26a [multiversion] Switch all of the targets over to use the
TargetIRAnalysis access path directly rather than implementing getTTI.

This even removes getTTI from the interface. It's more efficient for
each target to just register a precise callback that creates their
specific TTI.

As part of this, all of the targets which are building their subtargets
individually per-function now build their TTI instance with the function
and thus look up the correct subtarget and cache it. NVPTX, R600, and
XCore currently don't leverage this functionality, but its trivial for
them to add it now.

llvm-svn: 227735
2015-02-01 13:20:00 +00:00
Chandler Carruth ee642690ea [multiversion] Remove a false freedom to leave the TargetMachine pointer
null.

For some reason some of the original TTI code supported a null target
machine. This seems to have been legacy, and I made matters worse when
refactoring this code by spreading that pattern further through the
various targets.

The TargetMachine can't actually be null, and it doesn't make sense to
support that use case. I've now consistently removed it and removed all
of the code trying to cope with that situation. This is probably good,
as several targets *didn't* cope with it being null despite the null
default argument in their constructors. =]

llvm-svn: 227734
2015-02-01 12:38:24 +00:00
Chandler Carruth d8b3e9a420 [PM] Remove a bunch of stale TTI creation method declarations. I nuked
their definitions, but forgot to clean up all the declarations which are
in different files.

llvm-svn: 227698
2015-02-01 00:22:15 +00:00
Chandler Carruth 93dcdc47db [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

llvm-svn: 227685
2015-01-31 11:17:59 +00:00
Chandler Carruth 705b185f90 [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00
Rafael Espindola ba31e27f0a Compute the ELF SectionKind from the flags.
Any code creating an MCSectionELF knows ELF and already provides the flags.

SectionKind is an abstraction used by common code that uses a plain
MCSection.

Use the flags to compute the SectionKind. This removes a lot of
guessing and boilerplate from the MCSectionELF construction.

llvm-svn: 227476
2015-01-29 17:33:21 +00:00
Eric Christopher 8b7706517c Move DataLayout back to the TargetMachine from TargetSubtargetInfo
derived classes.

Since global data alignment, layout, and mangling is often based on the
DataLayout, move it to the TargetMachine. This ensures that global
data is going to be layed out and mangled consistently if the subtarget
changes on a per function basis. Prior to this all targets(*) have
had subtarget dependent code moved out and onto the TargetMachine.

*One target hasn't been migrated as part of this change: R600. The
R600 port has, as a subtarget feature, the size of pointers and
this affects global data layout. I've currently hacked in a FIXME
to enable progress, but the port needs to be updated to either pass
the 64-bitness to the TargetMachine, or fix the DataLayout to
avoid subtarget dependent features.

llvm-svn: 227113
2015-01-26 19:03:15 +00:00
Rafael Espindola 12ca34f53f Bring r226038 back.
No change in this commit, but clang was changed to also produce trivial comdats when
needed.

Original message:

Don't create new comdats in CodeGen.

This patch stops the implicit creation of comdats during codegen.

Clang now sets the comdat explicitly when it is required. With this patch clang and gcc
now produce the same result in pr19848.

llvm-svn: 226467
2015-01-19 15:16:06 +00:00