Now instead of changing it to the new format and then linking, it just
handles the old format while copying it over.
The main differences are:
* There is no rauw in the source module.
* An old format input is always upgraded.
The first item helps with having a sane API that passes in a GV list to
the linker.
The second one is a small step in deprecating the old format.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254907 91177308-0d34-0410-b5e6-96231b3b80d8
Creates a module and performs necessary renaming/promotion of locals
that may be exported to another module.
Split out of D15024.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254802 91177308-0d34-0410-b5e6-96231b3b80d8
Before this patch the diagnostic handler was optional. If it was not
passed, the one in the LLVMContext was used.
That is probably not a pattern we want to follow. If each area has an
optional callback, there is a sea of callbacks and it is hard to follow
which one is called.
Doing this also found cases where the callback is a nice addition, like
testing that no errors or warnings are reported.
The other option is to always use the diagnostic handler in the
LLVMContext. That has a few problems
* To implement the C API we would have to set the diag handler and then
set it back to the original value.
* Code that creates the context might be far away from code that wants
the diagnostics.
I do have a patch that implements the second option and will send that as
an RFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254777 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Fix import from module with appending var, which cannot be imported. The
first fix is to remove an overly-aggressive error check.
The second fix is to deal with restructuring introduced to the module
linker yesterday in r254418 (actually, this fix was included already
in r254559, just added some additional cleanup).
Test by Mehdi Amini.
Reviewers: joker.eph, rafael
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D15156
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254624 91177308-0d34-0410-b5e6-96231b3b80d8
There is no real reason the index has to have the concept of an
exporting Module. We should be able to have one single unique
instance of the Index, and it should be read-only after creation
for the whole ThinLTO processing.
The linker plugin should be able to process multiple modules (in
parallel or in sequence) with the same index.
The only reason the ExportingModule was present seems to be to
implement hasExportedFunctions() that is used by the Module linker
to decide what to do with the current Module.
For now I replaced it with a query to the map of Modules path to
see if this module was declared in the Index and consider that if
it is the case then it is probably exporting function.
On the long term the Linker interface needs to evolve and this
call should not be needed anymore.
From: Mehdi Amini <mehdi.amini@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254581 91177308-0d34-0410-b5e6-96231b3b80d8
This replaces DoNotLinkFromSource with ValuesToLink. It also moves the
computation of ValuesToLink earlier.
It is a bit simpler and an important step in slitting the linker into an
ir mover and a linker proper.
The test change is because we now avoid creating dead declarations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254559 91177308-0d34-0410-b5e6-96231b3b80d8
Having to import an alias as declaration is not thinlto specific.
The test difference are because when we already have a decl and we are
not importing it, we just leave the decl alone.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254556 91177308-0d34-0410-b5e6-96231b3b80d8
This was an omission when handling COFF style comdats with local keys.
Should fix the sanitizer-windows bot.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254543 91177308-0d34-0410-b5e6-96231b3b80d8
We were failing to copy the fact that the GV is weak and in the case of
an alias, producing invalid IR.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254538 91177308-0d34-0410-b5e6-96231b3b80d8
The linker never takes ownership of a module or changes which module it
is refering to, making it natural to use references.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254449 91177308-0d34-0410-b5e6-96231b3b80d8
It was only used from LTO for a debug feature, and LTO can just create
another linker.
It is pretty odd to have a method to reset the module in the middle of a
link. It would make IdentifiedStructTypes inconsistent with the Module
for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254434 91177308-0d34-0410-b5e6-96231b3b80d8
It has to be a bit special because:
* materializeInitFor is not really supposed to call replaceAllUsesWith.
The caller has a plain variable with Dst and expects just the
initializer to be set, not for it to be removed.
* Calling mutateType as we used to do before gets some type
inconsistency which breaks the bitcode writer.
* If linkAppendingVarProto create a dest decl with the correct type to
avoid the above problems, it needs to put the original dst init in
some side table for materializeInitFor to use.
In the end the simplest solution seems to be to just have
linkAppendingVarProto do all the work and set ValueMap[SrcGV to avoid
recursion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254424 91177308-0d34-0410-b5e6-96231b3b80d8
The difference is that now we don't error on out-of-comdat access to
internal global values. We copy them instead. This seems to match the
expectation of COFF linkers (see pr25686).
Original message:
Start deciding earlier what to link.
A traditional linker is roughly split in symbol resolution and
"copying
stuff".
The two tasks are badly mixed in lib/Linker.
This starts splitting them apart.
With this patch there are no direct call to linkGlobalValueBody or
linkGlobalValueProto. Everything is linked via WapValue.
This also includes a few fixes:
* A GV goes undefined if the comdat is dropped (comdat11.ll).
* We error if an internal GV goes undefined (comdat13.ll).
* We don't link an unused comdat.
The first two match the behavior of an ELF linker. The second one is
equivalent to running globaldce on the input.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254418 91177308-0d34-0410-b5e6-96231b3b80d8
A traditional linker is roughly split in symbol resolution and "copying
stuff".
The two tasks are badly mixed in lib/Linker.
This starts splitting them apart.
With this patch there are no direct call to linkGlobalValueBody or
linkGlobalValueProto. Everything is linked via WapValue.
This also includes a few fixes:
* A GV goes undefined if the comdat is dropped (comdat11.ll).
* We error if an internal GV goes undefined (comdat13.ll).
* We don't link an unused comdat.
The first two match the behavior of an ELF linker. The second one is
equivalent to running globaldce on the input.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254336 91177308-0d34-0410-b5e6-96231b3b80d8
We were not handling the case where an entry must be dropped and the
destination module has no llvm.global_ctors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254241 91177308-0d34-0410-b5e6-96231b3b80d8
Now the ValueMapper has two callbacks. The first one maps the
declaration. The ValueMapper records the mapping and then materializes
the body/initializer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254209 91177308-0d34-0410-b5e6-96231b3b80d8
They are as much trouble as aliases to declarations. They are requiring
the code generator to define a symbol with the same value as another
symbol, but the second symbol is undefined.
If representing this is important for some optimization, we could add
support for available_externally aliases. They would be *required* to
point to a declaration (or available_externally definition).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254170 91177308-0d34-0410-b5e6-96231b3b80d8
The new function import pass exposed an issue when we import references
to local values on multiple importing passes. They are renamed on each
import pass, and we need to ensure that the already promoted and renamed
references existing in the dest module are correctly identified and
updated so that they aren't spuriously renamed again (due to a perceived
conflict with the newly linked reference).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254009 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The patch to move metadata linking after global value linking didn't
correctly map unmaterialized global values to null as desired. They
were in fact mapped to the source copy. It largely worked by accident
since most module linker clients destroyed the source module which
caused the source GVs to be replaced by null, but caused a failure with
LTO linking on Windows:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312869.html
The problem is that a null return value from materializeValueFor is
handled by mapping the value to self. This is the desired behavior when
materializeValueFor is passed a non-GlobalValue. The problem is how to
distinguish that case from the case where we really do want to map to
null.
This patch addresses this by passing in a new flag to the value mapper
indicating that unmapped global values should be mapped to null. Other
Value types are handled as before.
Note that the documented behavior of asserting on unmapped values when
the flag RF_IgnoreMissingValues isn't set is currently disabled with
FIXME notes due to bootstrap failures. I modified these disabled asserts
so when they are eventually enabled again it won't assert for the
unmapped values when the new RF_NullMapMissingGlobalValues flag is set.
I also considered using a callback into the value materializer, but a
flag seemed cleaner given that there are already existing flags.
I also considered modifying materializeValueFor to return the input
value when we want to map to source and then treat a null return
to mean map to null. However, there are other value materializer
subclasses that implement materializeValueFor, and they would all need
to be audited and the return values possibly changed, which seemed
error-prone.
Reviewers: dexonsmith, joker.eph
Subscribers: pcc, llvm-commits
Differential Revision: http://reviews.llvm.org/D14682
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253170 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The module linker lazy links some "discardable if unused" global
values (e.g. linkonce), materializing and linking them only
if they are referenced in the module. If a comdat group contains a
linkonce member that is not referenced, however, it would not be
materialized and linked, leading to an incomplete comdat group.
If there are other object files not part of the same LTO link that also
define and use that comdat group, the linker may select the incomplete
group leading to link time unsats.
To solve this, whenever a global value body is linked, make sure we
materialize any other members of the same comdat group that are not yet
materialized. This ensures they are in the lazy link list and get linked
as well.
Added new test and adjusted old test to remove parts that didn't
make sense with fix.
Reviewers: rafael
Subscribers: dexonsmith, davidxl, llvm-commits
Differential Revision: http://reviews.llvm.org/D14516
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252647 91177308-0d34-0410-b5e6-96231b3b80d8
Ensure WeakAny variables are imported as ExternalWeak declarations. To
handle WeakAny more consistently and fix this issue:
1) Update helper doImportAsDefinition to properly flag WeakAny variables
and aliases as not importing defintions.
Update callers of doImportAsDefinition to remove now redundant checks for
WeakAny aliases, or ignore aliases, as appropriate.
2) Add any !doImportAsDefinition GVs to DoNotLinkFromSource set during
linking of the GV prototype, where we usually add GVs to the
DoNotLinkFromSource set for other reasons.
Remove now unnecessary adding of WeakAny aliases to
DoNotLinkFromSource set from copyGlobalAliasProto.
Remove now unnecessary guard against linking non-imported function
bodies from ModuleLinker::run.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252626 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This reverts commit r251965.
Restore "Move metadata linking after lazy global materialization/linking."
This restores commit r251926, with fixes for the LTO bootstrapping bot
failure.
The bot failure was caused by references from debug metadata to
otherwise unreferenced globals. Previously, this caused the lazy linking
to link in their defs, which is unnecessary. With this patch, because
lazy linking is complete when we encounter the metadata reference, the
materializer created a declaration. For definitions such as aliases and
comdats, it is illegal to have a declaration. Furthermore, metadata
linking should not change code generation. Therefore, when linking of
global value bodies is complete, the materializer will simply return
nullptr as the new reference for the linked metadata.
This change required fixing a different test to ensure there was a
real reference to a linkonce global that was only being reference from
metadata.
Note that the new changes to the only-needed-named-metadata.ll test
illustrate an issue with llvm-link -only-needed handling of comdat
groups, whereby it may result in an incomplete comdat group. I note this
in the test comments, but the issue is orthogonal to this patch (it can
be reproduced without any metadata at head).
Reviewers: dexonsmith, rafael, tra
Subscribers: tobiasvk, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D14447
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252320 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, subprograms contained a metadata reference to the function they
described. Because most clients need to get or set a subprogram for a given
function rather than the other way around, this created unneeded inefficiency.
For example, many passes needed to call the function llvm::makeSubprogramMap()
to build a mapping from functions to subprograms, and the IR linker needed to
fix up function references in a way that caused quadratic complexity in the IR
linking phase of LTO.
This change reverses the direction of the edge by storing the subprogram as
function-level metadata and removing DISubprogram's function field.
Since this is an IR change, a bitcode upgrade has been provided.
Fixes PR23367. An upgrade script for textual IR for out-of-tree clients is
attached to the PR.
Differential Revision: http://reviews.llvm.org/D14265
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252219 91177308-0d34-0410-b5e6-96231b3b80d8
When converting an alias to a non-alias when the aliasee is not
imported, ensure that the linkage type is set to external so that it is
a valid linkage type. Added a test case that exposed this issue.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252054 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Currently, named metadata is linked before the LazilyLinkGlobalValues
list is walked and materialized/linked. As a result, references
from DISubprogram and DIGlobalVariable metadata to yet unmaterialized
functions and variables cause them to be added to the lazy linking
list and their definitions are materialized and linked.
This makes the llvm-link -only-needed option not have the intended
effect when debug information is present, as the otherwise unneeded
functions/variables are still linked in.
Additionally, for ThinLTO I have implemented a mechanism to only link
in debug metadata needed by imported functions. Moving named metadata
linking after lazy GV linking will facilitate applying this mechanism
to the LTO and "llvm-link -only-needed" cases as well.
Reviewers: dexonsmith, tra, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14195
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251926 91177308-0d34-0410-b5e6-96231b3b80d8
This restores commit r251837, with the new library dependence added to
llvm-link/Makefile to address bot failures.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251866 91177308-0d34-0410-b5e6-96231b3b80d8
