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Commit Graph

180 Commits

Author SHA1 Message Date
Fangrui Song
dd6e19a41c [IR] Rename comdat noduplicates to comdat nodeduplicate
In the textual format, `noduplicates` means no COMDAT/section group
deduplication is performed. Therefore, if both sets of sections are retained, and
they happen to define strong external symbols with the same names,
there will be a duplicate definition linker error.

In PE/COFF, the selection kind lowers to `IMAGE_COMDAT_SELECT_NODUPLICATES`.
The name describes the corollary instead of the immediate semantics.  The name
can cause confusion to other binary formats (ELF, wasm) which have implemented/
want to implement the "no deduplication" selection kind. Rename it to be clearer.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D106319
2021-07-20 12:47:10 -07:00
serge-sans-paille
73bc91a5e6 Revert "[NFC] remove explicit default value for strboolattr attribute in tests"
This reverts commit bda6e5bee04c75b1f1332b4fd1ac4e8ef6c3c247.

See https://lab.llvm.org/buildbot/#/builders/109/builds/15424 for instance
2021-05-24 19:43:40 +02:00
serge-sans-paille
1f63b26006 [NFC] remove explicit default value for strboolattr attribute in tests
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.

This is a preliminary commit for https://reviews.llvm.org/D99080
2021-05-24 19:31:04 +02:00
Jin Lin
673715d427 Preserve the lexical order for global variables during llvm-link merge
The order of global variables is generated in the order of recursively materializing variables if the global variable has the attribute of hasLocalLinkage or hasLinkOnceLinkage during the module merging. In practice, it is often the exact reverse of source order. This new order may cause performance regression.

The change is to preserve the original lexical order for global variables.

Reviewed By: jdoerfert, dexonsmith

Differential Revision: https://reviews.llvm.org/D94202
2021-04-26 10:11:34 -07:00
Matt Arsenault
efe6c99b52 Reapply "OpaquePtr: Turn inalloca into a type attribute"
This reverts commit 07e46367baeca96d84b03fa215b41775f69d5989.
2021-03-29 08:55:30 -04:00
Oliver Stannard
0914bea32c Revert "Reapply "OpaquePtr: Turn inalloca into a type attribute""
Reverting because test 'Bindings/Go/go.test' is failing on most
buildbots.

This reverts commit fc9df309917e57de704f3ce4372138a8d4a23d7a.
2021-03-29 11:32:22 +01:00
Matt Arsenault
403cadc380 Reapply "OpaquePtr: Turn inalloca into a type attribute"
This reverts commit 20d5c42e0ef5d252b434bcb610b04f1cb79fe771.
2021-03-28 13:35:21 -04:00
Nico Weber
755e1b95c9 Revert "OpaquePtr: Turn inalloca into a type attribute"
This reverts commit 4fefed65637ec46c8c2edad6b07b5569ac61e9e5.
Broke check-clang everywhere.
2021-03-28 13:02:52 -04:00
Matt Arsenault
9b63996812 OpaquePtr: Turn inalloca into a type attribute
I think byval/sret and the others are close to being able to rip out
the code to support the missing type case. A lot of this code is
shared with inalloca, so catch this up to the others so that can
happen.
2021-03-28 11:12:23 -04:00
Leonard Chan
bf4eac0c1d [llvm] Change DSOLocalEquivalent type if the underlying global value type changes
We encountered an issue where LTO running on IR that used the DSOLocalEquivalent
constant would result in bad codegen. The underlying issue was ValueMapper wasn't
properly handling DSOLocalEquivalent, so this just adds the machinery for handling
it. This code path is triggered by a fix to DSOLocalEquivalent::handleOperandChangeImpl
where DSOLocalEquivalent could potentially not have the same type as its underlying GV.

This updates DSOLocalEquivalent::handleOperandChangeImpl to change the type if
the GV type changes and handles this constant in ValueMapper.

Differential Revision: https://reviews.llvm.org/D97978
2021-03-09 15:09:48 -08:00
Nashe Mncube
78595a3c7a [llvm-link] fix IRMover returning wrong modified vector type
Modified scalable vector types weren't correctly returned at link-time.
The previous behaviour was a FixedVectorType was constructed
when expecting a ScalableVectorType. This commit has added a regression
test which re-creates the failure as well as a fix.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D96953
2021-02-22 11:29:42 +00:00
Sergey Dmitriev
d19ff967e7 [llvm-link] Fix for an assertion when linking global with appending linkage
This patch fixes llvm-link assertion when linking external variable
declaration with a definition with appending linkage.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D95126
2021-01-23 00:10:42 -08:00
Matt Arsenault
80d9c38cea Linker: Fix linking of byref types
This wasn't properly remapping the type like with the other
attributes, so this would end up hitting a verifier error after
linking different modules using byref.
2020-11-17 11:02:04 -05:00
Matt Arsenault
e3bfefd3cc Reapply "OpaquePtr: Add type to sret attribute"
This reverts commit eb9f7c28e5fe6d75fed3587023e17f2997c8024b.

Previously this was incorrectly handling linking of the contained
type, so this merges the fixes from D88973.
2020-10-16 11:05:02 -04:00
Itay Bookstein
c00c4a1533 [IR] Add missing GlobalAlias copying of ThreadLocalMode attribute
Summary:
Previously, GlobalAlias::copyAttributesFrom did not preserve ThreadLocalMode,
causing incorrect IR generation in IR linking flows. This patch pushes the code
responsible for copying this attribute from GlobalVariable::copyAttributesFrom
down to GlobalValue::copyAttributesFrom so that it is shared by GlobalAlias.
Fixes PR46297.

Reviewers: tejohnson, pcc, hans

Reviewed By: tejohnson, hans

Subscribers: hiraditya, ibookstein, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81605
2020-06-16 20:15:27 -07:00
Jin Lin
47d7e3782b Fix conflict value for metadata "Objective-C Garbage Collection" in the mix of swift and Objective-C bitcode
Summary:
The change is to fix conflict value for metadata "Objective-C Garbage Collection" in the mix of swift and Objective-C bitcode.
The purpose is to provide the support of LTO for swift and Objective-C mixed project.

Reviewers: rjmccall, ahatanak, steven_wu

Reviewed By: rjmccall, steven_wu

Subscribers: manmanren, mehdi_amini, hiraditya, dexonsmith, llvm-commits, jinlin

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71219
2020-03-11 13:26:06 -07:00
David Blaikie
f21a88cbf6 IR Linking: Support merging Warning+Max module metadata flags
Summary:
Debug Info Version was changed to use "Max" instead of "Warning" per the
original design intent - but this maxes old/new IR unlinkable, since
mismatched merge styles are a linking failure.

It seems possible/maybe reasonable to actually support the combination
of these two flags: Warn, but then use the maximum value rather than the
first value/earlier module's value.

Reviewers: tejohnson

Differential Revision: https://reviews.llvm.org/D74257
2020-02-07 16:29:58 -08:00
Fangrui Song
2d0a36fd96 Migrate function attribute "no-frame-pointer-elim"="false" to "frame-pointer"="none" as cleanups after D56351 2019-12-24 16:27:51 -08:00
Fangrui Song
d9c5df08b1 Migrate function attribute "no-frame-pointer-elim" to "frame-pointer"="all" as cleanups after D56351 2019-12-24 15:57:33 -08:00
Tim Northover
42e839cbcd Reapply: IR: add optional type to 'byval' function parameters
When we switch to opaque pointer types we will need some way to describe
how many bytes a 'byval' parameter should occupy on the stack. This adds
a (for now) optional extra type parameter.

If present, the type must match the pointee type of the argument.

The original commit did not remap byval types when linking modules, which broke
LTO. This version fixes that.

Note to front-end maintainers: if this causes test failures, it's probably
because the "byval" attribute is printed after attributes without any parameter
after this change.

llvm-svn: 362128
2019-05-30 18:48:23 +00:00
James Y Knight
40395d6771 Remove irrelevant references to legacy git repositories from
compiler identification lines in test-cases.

(Doing so only because it's then easier to search for references which
are actually important and need fixing.)

llvm-svn: 351200
2019-01-15 16:18:52 +00:00
Scott Linder
538dfe3e23 Implement -frecord-command-line (-frecord-gcc-switches)
Implement options in clang to enable recording the driver command-line
in an ELF section.

Implement a new special named metadata, llvm.commandline, to support
frontends embedding their command-line options in IR/ASM/ELF.

This differs from the GCC implementation in some key ways:

* In GCC there is only one command-line possible per compilation-unit,
  in LLVM it mirrors llvm.ident and multiple are allowed.
* In GCC individual options are separated by NULL bytes, in LLVM entire
  command-lines are separated by NULL bytes. The advantage of the GCC
  approach is to clearly delineate options in the face of embedded
  spaces. The advantage of the LLVM approach is to support merging
  multiple command-lines unambiguously, while handling embedded spaces
  with escaping.

Differential Revision: https://reviews.llvm.org/D54487
Clang Differential Revision: https://reviews.llvm.org/D54489

llvm-svn: 349155
2018-12-14 15:38:15 +00:00
David Blaikie
4b95f4ad7c llvm-link: Improve diagnostic for module-level metadata mismatch
This might produce hard to read/illegible diagnostics for especially
weird/non-trivial module metadata but integers are about all we are
using these days, so seems more useful than not.

Patch based on work by Kristina Brooks - thanks!

Differential Revision: https://reviews.llvm.org/D52952

llvm-svn: 344011
2018-10-09 01:17:27 +00:00
Matt Arsenault
8dff882c45 Fix asserts when linking wrong address space declarations
llvm-svn: 342858
2018-09-24 04:42:14 +00:00
Shiva Chen
a2029fa58e [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is

!DILabel(scope: !1, name: "foo", file: !2, line: 3)

We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is

llvm.dbg.label(metadata !1)

It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.

We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.

Differential Revision: https://reviews.llvm.org/D45024

Patch by Hsiangkai Wang.

llvm-svn: 331841
2018-05-09 02:40:45 +00:00
Scott Linder
6206221265 [DebugInfo] Add remaining files to r325970
Add files which I missed in the original check-in

llvm-svn: 325973
2018-02-23 23:13:18 +00:00
Rafael Espindola
a78a4abcc4 Revert "[IRMover] Implement name based structure type mapping"
This reverts commit r325686.

There was a misunderstanding and this has not been approved yet.

llvm-svn: 325715
2018-02-21 20:12:18 +00:00
Eugene Leviant
ea05773277 [IRMover] Implement name based structure type mapping
Differential revision: https://reviews.llvm.org/D43199

llvm-svn: 325686
2018-02-21 15:13:48 +00:00
Adrian Prantl
6b62dff720 Verifier: Ignore CUs pulled in by ODR-uniqued types.
When more than one Module is imported into the same context, such as during
an LTO build before linking the modules, ODR type uniquing may cause types
to point to a different CU. This check does not make sense in this case.

This fixes the error reported in PR34944.

https://bugs.llvm.org/show_bug.cgi?id=34944
rdar://problem/34940685

This reapplies a cleaner implementation of r316049.

llvm-svn: 316052
2017-10-18 01:11:01 +00:00
Adrian Prantl
a8aee7c70a Revert "Verifier: Ignore CUs pulled in by ODR-uniqued types."
This reverts commit r316049.

llvm-svn: 316050
2017-10-18 00:54:31 +00:00
Adrian Prantl
cb310a1b82 Verifier: Ignore CUs pulled in by ODR-uniqued types.
When more than one Module is imported into the same context, such as during
an LTO build before linking the modules, ODR type uniquing may cause types
to point to a different CU. This check does not make sense in this case.

This fixes the error reported in PR34944.

https://bugs.llvm.org/show_bug.cgi?id=34944
rdar://problem/34940685

llvm-svn: 316049
2017-10-18 00:49:31 +00:00
Jonas Devlieghere
2780d34fe1 Re-land "[llvm-dwarfdump] Print type names in DW_AT_type DIEs"
This patch adds printing for DW_AT_type DIEs like it is already the case
for DW_AT_specification DIEs. This is a rather naive approach and only a
start. We should have pretty printers for different languages.

Recommit after being reverted in r315299.

Differential revision: https://reviews.llvm.org/D36993

llvm-svn: 315316
2017-10-10 14:15:25 +00:00
Jonas Devlieghere
0333c4b70c Revert "[llvm-dwarfdump] Print type names in DW_AT_type DIEs"
This reverts commit r315297.

llvm-svn: 315299
2017-10-10 11:49:56 +00:00
Jonas Devlieghere
8126b68ab8 [llvm-dwarfdump] Print type names in DW_AT_type DIEs
This patch adds printing for DW_AT_type DIEs like it is already the case
for DW_AT_specification DIEs. This is a rather naive approach and only a
start. We should have pretty printers for different languages.

Differential revision: https://reviews.llvm.org/D36993

llvm-svn: 315297
2017-10-10 11:24:41 +00:00
Benoit Belley
b3db052a71 [Linker] PR33527 - Linker::LinkOnlyNeeded should import AppendingLinkage globals
Linker::LinkOnlyNeeded should always import globals with
AppendingLinkage.

This resolves PR33527.

Differential Revision: https://reviews.llvm.org/D34448

llvm-svn: 310522
2017-08-09 20:58:39 +00:00
Florian Hahn
f4278d3016 [Linker] Add directives to support mixing ARM/Thumb module-level inline asm.
Summary:
By prepending `.text .thumb .balign 2` to the module-level inline
assembly from a Thumb module, the assembler will generate the assembly
from that module as Thumb, even if the destination module uses an ARM
triple. Similar directives are used for module-level inline assembly in
ARM modules.

The alignment and instruction set are reset based on the target triple
before emitting the first function label.

Reviewers: olista01, tejohnson, echristo, t.p.northover, rafael

Reviewed By: echristo

Subscribers: aemerson, javed.absar, eraman, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D34622

llvm-svn: 307772
2017-07-12 11:52:28 +00:00
Konstantin Zhuravlyov
d382d6f3fc Enhance synchscope representation
OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
  global and local memory. These scopes restrict how synchronization is
  achieved, which can result in improved performance.

  This change extends existing notion of synchronization scopes in LLVM to
  support arbitrary scopes expressed as target-specific strings, in addition to
  the already defined scopes (single thread, system).

  The LLVM IR and MIR syntax for expressing synchronization scopes has changed
  to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
  replaces *singlethread* keyword), or a target-specific name. As before, if
  the scope is not specified, it defaults to CrossThread/System scope.

  Implementation details:
    - Mapping from synchronization scope name/string to synchronization scope id
      is stored in LLVM context;
    - CrossThread/System and SingleThread scopes are pre-defined to efficiently
      check for known scopes without comparing strings;
    - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
      the bitcode.

Differential Revision: https://reviews.llvm.org/D21723

llvm-svn: 307722
2017-07-11 22:23:00 +00:00
Florian Hahn
20ec5bbffb [Linker] Remove warning when linking ARM and Thumb IR modules.
Summary:
This patch updates Triple::isCompatibleWith to make armxx and thumbxx
triples compatible, as long as the subarch, vendor, os, envorionment and
object format match. Thumb/ARM code generation should be controlled
using the thumb-mode per-function target feature rather than by the
triple to allow mixing Thumb and ARM functions.

D33448 updates Clang's codegen to add thumb-mode for all functions with
armxx or thumbxx triples.

Reviewers: echristo, t.p.northover, rafael, kristof.beyls, rengolin, tejohnson

Reviewed By: tejohnson

Subscribers: rinon, eugenis, pcc, srhines, aemerson, mehdi_amini, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D33287

llvm-svn: 304884
2017-06-07 09:17:01 +00:00
Teresa Johnson
b0011ef93b Support for taking the max of module flags when linking, use for PIE/PIC
Summary:
Add Max ModFlagBehavior, which can be used to take the max of two
module flag values when merging modules. Use it for the PIE and PIC
levels.

This avoids an error when we try to import from a module built -fpic
into a module built -fPIC, for example. For both PIE and PIC levels,
this will be legal, since the code generation gets more conservative
as the level is increased. Therefore we can take the max instead of
somehow trying to block importing between modules compiled with
different levels.

Reviewers: tmsriram, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D33418

llvm-svn: 303590
2017-05-23 00:08:00 +00:00
Jonas Devlieghere
9840ae61ae [Linker] Provide callback for internalization
Differential Revision: https://reviews.llvm.org/D30738

llvm-svn: 297649
2017-03-13 18:08:11 +00:00
Peter Collingbourne
1085bb25fe Linker: Remove unnecessary call to copyMetadata in IRLinker::linkGlobalVariable.
This was causing us to create duplicate metadata on global variables.
Debug info test case by Adrian Prantl, additional test cases by me.

Fixes PR31012.

Differential Revision: https://reviews.llvm.org/D26622

llvm-svn: 286905
2016-11-14 23:18:38 +00:00
Mehdi Amini
e957209890 Fix autoupgrade logic for Objective-C class properties module flag
Previous we were issuing an error when linking a module containing
the new Objective-C metadata structure for class properties with an
"old" one.
Now instead we downgrade the module flag so that the Objective-C
runtime does not expect the new metadata structure.

This is consistent with what ld64 is doing on binary files.

Differential Revision: https://reviews.llvm.org/D24620

llvm-svn: 281685
2016-09-16 00:38:18 +00:00
Duncan P. N. Exon Smith
6a8d2b6215 IR: Drop uniquing when an MDNode Value operand is deleted
This is a fix for PR28697.

An MDNode can indirectly refer to a GlobalValue, through a
ConstantAsMetadata.  When the GlobalValue is deleted, the MDNode operand
is reset to `nullptr`.  If the node is uniqued, this can lead to a
hard-to-detect cache invalidation in a Metadata map that's shared across
an LLVMContext.

Consider:

 1. A map from Metadata* to `T` called RemappedMDs.
 2. A node that references a global variable, `!{i1* @GV}`.
 3. Insert `!{i1* @GV} -> SomeT` in the map.
 4. Delete `@GV`, leaving behind `!{null} -> SomeT`.

Looking up the generic and uninteresting `!{null}` gives you `SomeT`,
which is likely related to `@GV`.  Worse, `SomeT`'s lifetime may be tied
to the deleted `@GV`.

This occurs in practice in the shared ValueMap used since r266579 in the
IRMover.  Other code that handles more than one Module (with different
lifetimes) in the same LLVMContext could hit it too.

The fix here is a partial revert of r225223: in the rare case that an
MDNode operand is a ConstantAsMetadata (i.e., wrapping a node from the
Value hierarchy), drop uniquing if it gets replaced with `nullptr`.
This changes step #4 above to leave behind `distinct !{null} -> SomeT`,
which can't be confused with the generic `!{null}`.

In theory, this can cause some churn in the LLVMContext's MDNode
uniquing map when Values are being deleted.  However:

  - The number of GlobalValues referenced from uniqued MDNodes is
    expected to be quite small.  E.g., the debug info metadata schema
    only references GlobalValues from distinct nodes.

  - Other Constants have the lifetime of the LLVMContext, whose teardown
    is careful to drop references before deleting the constants.

As a result, I don't expect a compile time regression from this change.

llvm-svn: 277625
2016-08-03 18:19:43 +00:00
Rafael Espindola
fe0a450fe1 Don't verify inputs to the Linker if ODR merging.
This fixes pr28072.

The point, as Duncan pointed out, is that the file is already
partially linked by just reading it.

Long term I think the solution is to make metadata owned by the module
and then the linker will lazily read it and be in charge of all the
linking. Running a verifier in each input will defeat the lazy
loading, but will be legal.

Right now we are at the unfortunate position that to support odr
merging we cannot verify the inputs, which mildly annoying (see test
update).

llvm-svn: 274148
2016-06-29 18:31:48 +00:00
Duncan P. N. Exon Smith
94512f24de DebugInfo: Remove MDString-based type references
Eliminate DITypeIdentifierMap and make DITypeRef a thin wrapper around
DIType*.  It is no longer legal to refer to a DICompositeType by its
'identifier:', and DIBuilder no longer retains all types with an
'identifier:' automatically.

Aside from the bitcode upgrade, this is mainly removing logic to resolve
an MDString-based reference to an actualy DIType.  The commits leading
up to this have made the implicit type map in DICompileUnit's
'retainedTypes:' field superfluous.

This does not remove DITypeRef, DIScopeRef, DINodeRef, and
DITypeRefArray, or stop using them in DI-related metadata.  Although as
of this commit they aren't serving a useful purpose, there are patchces
under review to reuse them for CodeView support.

The tests in LLVM were updated with deref-typerefs.sh, which is attached
to the thread "[RFC] Lazy-loading of debug info metadata":

  http://lists.llvm.org/pipermail/llvm-dev/2016-April/098318.html

llvm-svn: 267296
2016-04-23 21:08:00 +00:00
Rafael Espindola
7e0cfdf745 Fix recursive -only-needed.
We were assuming that only linkonce_odr GVs were lazy linked.

llvm-svn: 266995
2016-04-21 14:56:33 +00:00
Duncan P. N. Exon Smith
2288252887 IR: Enable debug info type ODR uniquing for forward decls
Add a new method, DICompositeType::buildODRType, that will create or
mutate the DICompositeType for a given ODR identifier, and use it in
LLParser and BitcodeReader instead of DICompositeType::getODRType.

The logic is as follows:

  - If there's no node, create one with the given arguments.
  - Else, if the current node is a forward declaration and the new
    arguments would create a definition, mutate the node to match the
    new arguments.
  - Else, return the old node.

This adds a missing feature supported by the current DITypeIdentifierMap
(which I'm slowly making redudant).  The only remaining difference is
that the DITypeIdentifierMap has a "the-last-one-wins" rule, whereas
DICompositeType::buildODRType has a "the-first-one-wins" rule.

For now I'm leaving behind DICompositeType::getODRType since it has
obvious, low-level semantics that are convenient for unit testing.

llvm-svn: 266786
2016-04-19 18:00:19 +00:00
Duncan P. N. Exon Smith
0c4233db2f IR: Use an explicit map for debug info type uniquing
Rather than relying on the structural equivalence of DICompositeType to
merge type definitions, use an explicit map on the LLVMContext that
LLParser and BitcodeReader consult when constructing new nodes.
Each non-forward-declaration DICompositeType with a non-empty
'identifier:' field is stored/loaded from the type map, and the first
definiton will "win".

This map is opt-in: clients that expect ODR types from different modules
to be merged must call LLVMContext::ensureDITypeMap.

  - Clients that just happen to load more than one Module in the same
    LLVMContext won't magically merge types.

  - Clients (like LTO) that want to continue to merge types based on ODR
    identifiers should opt-in immediately.

I have updated LTOCodeGenerator.cpp, the two "linking" spots in
gold-plugin.cpp, and llvm-link (unless -disable-debug-info-type-map) to
set this.

With this in place, it will be straightforward to remove the DITypeRef
concept (i.e., referencing types by their 'identifier:' string rather
than pointing at them directly).

llvm-svn: 266549
2016-04-17 03:58:21 +00:00
Adrian Prantl
fb3abba237 [PR27284] Reverse the ownership between DICompileUnit and DISubprogram.
Currently each Function points to a DISubprogram and DISubprogram has a
scope field. For member functions the scope is a DICompositeType. DIScopes
point to the DICompileUnit to facilitate type uniquing.

Distinct DISubprograms (with isDefinition: true) are not part of the type
hierarchy and cannot be uniqued. This change removes the subprograms
list from DICompileUnit and instead adds a pointer to the owning compile
unit to distinct DISubprograms. This would make it easy for ThinLTO to
strip unneeded DISubprograms and their transitively referenced debug info.

Motivation
----------

Materializing DISubprograms is currently the most expensive operation when
doing a ThinLTO build of clang.

We want the DISubprogram to be stored in a separate Bitcode block (or the
same block as the function body) so we can avoid having to expensively
deserialize all DISubprograms together with the global metadata. If a
function has been inlined into another subprogram we need to store a
reference the block containing the inlined subprogram.

Attached to https://llvm.org/bugs/show_bug.cgi?id=27284 is a python script
that updates LLVM IR testcases to the new format.

http://reviews.llvm.org/D19034
<rdar://problem/25256815>

llvm-svn: 266446
2016-04-15 15:57:41 +00:00
Adrian Prantl
d4a72b1280 Legalize the debug info in this testcase in anticipation of future Verifier improvements.
llvm-svn: 266017
2016-04-11 23:26:31 +00:00