This diff includes changes for the remaining _Fract and _Sat fixed point types.
```
signed short _Fract s_short_fract;
signed _Fract s_fract;
signed long _Fract s_long_fract;
unsigned short _Fract u_short_fract;
unsigned _Fract u_fract;
unsigned long _Fract u_long_fract;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
short _Fract short_fract;
_Fract fract;
long _Fract long_fract;
// Saturated fixed point types
_Sat signed short _Accum sat_s_short_accum;
_Sat signed _Accum sat_s_accum;
_Sat signed long _Accum sat_s_long_accum;
_Sat unsigned short _Accum sat_u_short_accum;
_Sat unsigned _Accum sat_u_accum;
_Sat unsigned long _Accum sat_u_long_accum;
_Sat signed short _Fract sat_s_short_fract;
_Sat signed _Fract sat_s_fract;
_Sat signed long _Fract sat_s_long_fract;
_Sat unsigned short _Fract sat_u_short_fract;
_Sat unsigned _Fract sat_u_fract;
_Sat unsigned long _Fract sat_u_long_fract;
// Aliased saturated fixed point types
_Sat short _Accum sat_short_accum;
_Sat _Accum sat_accum;
_Sat long _Accum sat_long_accum;
_Sat short _Fract sat_short_fract;
_Sat _Fract sat_fract;
_Sat long _Fract sat_long_fract;
```
This diff only allows for declaration of these fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches.
Differential Revision: https://reviews.llvm.org/D46911
llvm-svn: 334718
Summary:
This kind of functionality is useful to other project apart from clang.
LLDB works with version numbers a lot, but it does not have a convenient
abstraction for this. Moving this class to a lower level library allows
it to be freely used within LLDB.
Since this class is used in a lot of places in clang, and it used to be
in the clang namespace, it seemed appropriate to add it to the list of
adopted classes in LLVM.h to avoid prefixing all uses with "llvm::".
Also, I didn't find any tests specific for this class, so I wrote a
couple of quick ones for the more interesting bits of functionality.
Reviewers: zturner, erik.pilkington
Subscribers: mgorny, cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D47887
llvm-svn: 334399
// Primary fixed point types
signed short _Accum s_short_accum;
signed _Accum s_accum;
signed long _Accum s_long_accum;
unsigned short _Accum u_short_accum;
unsigned _Accum u_accum;
unsigned long _Accum u_long_accum;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
This diff only allows for declaration of the fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches. The saturated versions of these types and the equivalent _Fract types will also be added in future patches.
The tests included are for asserting that we can declare these types.
Fixed the test that was failing by not checking for dso_local on some
targets.
Differential Revision: https://reviews.llvm.org/D46084
llvm-svn: 333923
```
// Primary fixed point types
signed short _Accum s_short_accum;
signed _Accum s_accum;
signed long _Accum s_long_accum;
unsigned short _Accum u_short_accum;
unsigned _Accum u_accum;
unsigned long _Accum u_long_accum;
// Aliased fixed point types
short _Accum short_accum;
_Accum accum;
long _Accum long_accum;
```
This diff only allows for declaration of the fixed point types. Assignment and other operations done on fixed point types according to http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1169.pdf will be added in future patches. The saturated versions of these types and the equivalent `_Fract` types will also be added in future patches.
The tests included are for asserting that we can declare these types.
Differential Revision: https://reviews.llvm.org/D46084
llvm-svn: 333814
Summary: The blob data is unaligned, so we also should read it as such. Should fix the random failures with the sanitizer builds.
Reviewers: rsmith, v.g.vassilev
Reviewed By: v.g.vassilev
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D47247
llvm-svn: 333069
For example, given:
void fn() {
struct T *p0;
struct T { int i; } *p1;
}
-ast-print produced:
void fn() {
struct T { int i; } *p0;
struct T { int i; } *p1;
}
Compiling that fails with a redefinition error.
Given:
void fn() {
struct T *p0;
struct __attribute__((deprecated)) T *p1;
}
-ast-print dropped the attribute.
Details:
For a tag specifier (that is, struct/union/class/enum used as a type
specifier in a declaration) that was also a tag declaration (that is,
first occurrence of the tag) or tag redeclaration (that is, later
occurrence that specifies attributes or a member list), clang printed
the tag specifier as either (1) the full tag definition if one
existed, or (2) the first tag declaration otherwise. Redefinition
errors were sometimes introduced, as in the first example above. Even
when that was impossible because no member list was ever specified,
attributes were sometimes lost, thus changing semantics and
diagnostics, as in the second example above.
This patch fixes a major culprit for these problems. It does so by
creating an ElaboratedType with a new OwnedDecl member wherever an
occurrence of a tag type is a (re)declaration of that tag type.
PrintingPolicy's IncludeTagDefinition used to trigger printing of the
member list, attributes, etc. for a tag specifier by using a tag
(re)declaration selected as described above. Now, it triggers the
same thing except it uses the tag (re)declaration stored in the
OwnedDecl. Of course, other tooling can now make use of the new
OwnedDecl as well.
Also, to be more faithful to the original source, this patch
suppresses printing of attributes inherited from previous
declarations.
Reviewed by: rsmith, aaron.ballman
Differential Revision: https://reviews.llvm.org/D45463
llvm-svn: 332281
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
FunctionProtoType.
We previously re-evaluated the expression each time we wanted to know whether
the type is noexcept or not. We now evaluate the expression exactly once.
This is not quite "no functional change": it fixes a crasher bug during AST
deserialization where we would try to evaluate the noexcept specification in a
situation where we have not deserialized sufficient portions of the AST to
permit such evaluation.
llvm-svn: 331428
This is not yet part of any C++ working draft, and so is controlled by the flag
-fchar8_t rather than a -std= flag. (The GCC implementation is controlled by a
flag with the same name.)
This implementation is experimental, and will be removed or revised
substantially to match the proposal as it makes its way through the C++
committee.
llvm-svn: 331244
When a '>>' token is split into two '>' tokens (in C++11 onwards), or (as an
extension) when we do the same for other tokens starting with a '>', we can't
just use a location pointing to the first '>' as the location of the split
token, because that would result in our miscomputing the length and spelling
for the token. As a consequence, for example, a refactoring replacing 'A<X>'
with something else would sometimes replace one character too many, and
similarly diagnostics highlighting a template-id source range would highlight
one character too many.
Fix this by creating an expansion range covering the first character of the
'>>' token, whose spelling is '>'. For this to work, we generalize the
expansion range of a macro FileID to be either a token range (the common case)
or a character range (used in this new case).
llvm-svn: 331155
Right now we only use this information in one place, immediately after
we calculate it, but it's still nice information to have. The Swift
project is going to use this to tidy up its "API notes" feature (see
past discussion on cfe-dev that never quite converged).
Reviewed by Bruno Cardoso Lopes.
llvm-svn: 330452
framework module SomeKitCore {
...
export_as SomeKit
}
Given the module above, while generting autolink information during
codegen, clang should to emit '-framework SomeKitCore' only if SomeKit
was not imported in the relevant TU, otherwise it should use '-framework
SomeKit' instead.
rdar://problem/38269782
llvm-svn: 330152
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:
archtype
cas
classs
checkk
compres
definit
frome
iff
inteval
ith
lod
methode
nd
optin
ot
pres
statics
te
thru
Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)
Differential revision: https://reviews.llvm.org/D44188
llvm-svn: 329399
r327219 added wrappers to std::sort which randomly shuffle the container before
sorting. This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.
llvm-svn: 328636
The patch adds nocf_check target independent attribute for disabling checks that were enabled by cf-protection flag.
The attribute can be appertained to functions and function pointers.
Attribute name follows GCC's similar attribute name.
Differential Revision: https://reviews.llvm.org/D41880
llvm-svn: 327768
When parsing comments, for example, for -Wdocumentation, slightly different
behaviour occurs when -fparse-all-comments is specified. However, these
differences are subtle:
1. All comments are saved during parsing, regardless of whether they are doc
comments or not.
2. "Maybe-doc" comments, like <, !, etc, are saved as such, instead of marking
them as ordinary comments. The maybe-doc type of comment is never saved
otherwise. (Warning on these is the impetus of -Wdocumentation.)
3. All comments are treated as doc comments in ASTContext, even if they are ordinary.
This change moves the logic for checking CommentOptions.ParseAllComments closer
to where it has an effect. The overall logic is unchanged, but checks of the
ParseAllComments flag are now done where the effect will be clearer.
Subscribers: cfe-commits
llvm-svn: 326512
Original change:
[NFC] Move CommentOpts checks to the call sites that depend on it.
When parsing comments, for example, for -Wdocumentation, slightly different
behaviour occurs when -fparse-all-comments is specified. However, these
differences are subtle:
1. All comments are saved during parsing, regardless of whether they are doc comments or not.
2. "Maybe-doc" comments, like //<, //!, etc, are saved as such, instead of marking them as ordinary comments. The maybe-doc type of comment is never saved otherwise. (Warning on these is the impetus of -Wdocumentation.)
3. All comments are treated as doc comments in ASTContext, even if they are ordinary.
This change moves the logic for checking CommentOptions.ParseAllComments closer
to where it has an effect. The overall logic is unchanged, but checks of the
ParseAllComments flag are now done where the effect will be clearer.
llvm-svn: 326508
When parsing comments, for example, for -Wdocumentation, slightly different
behaviour occurs when -fparse-all-comments is specified. However, these
differences are subtle:
1. All comments are saved during parsing, regardless of whether they are doc
comments or not.
2. "Maybe-doc" comments, like //<, //!, etc, are saved as such, instead of
marking them as ordinary comments. The maybe-doc type of comment is never
saved otherwise. (Warning on these is the impetus of -Wdocumentation.)
3. All comments are treated as doc comments in ASTContext, even if they are
ordinary.
This change moves the logic for checking CommentOptions.ParseAllComments closer
to where it has an effect. The overall logic is unchanged, but checks of the
ParseAllComments flag are now done where the effect will be clearer.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D43663
llvm-svn: 326501
This patch removes the HashString function from StringExtraces and
replaces its uses with calls to djbHash from DJB.h.
This change is *almost* NFC. While the algorithm is identical, the
djbHash implementation in StringExtras used 0 as its default seed while
the implementation in DJB uses 5381. The latter has been shown to result
in less collisions and improved avalanching and is used by the DWARF
accelerator tables.
Because some test were implicitly relying on the hash order, I've
reverted to using zero as a seed for the following two files:
lld/include/lld/Core/SymbolTable.h
llvm/lib/Support/StringMap.cpp
Differential revision: https://reviews.llvm.org/D43615
llvm-svn: 326091
It looks like some of our tests depend on the ordering of hashed values.
I'm reverting my changes while I try to reproduce and fix this locally.
Failing builds:
lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/18388
lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/6743
lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/15607
llvm-svn: 326082
This removes the HashString function from StringExtraces and replaces
its uses with calls to djbHash from DJB.h
This is *almost* NFC. While the algorithm is identical, the djbHash
implementation in StringExtras used 0 as its seed while the
implementation in DJB uses 5381. The latter has been shown to result in
less collisions and improved avalanching.
https://reviews.llvm.org/D43615
(cherry picked from commit 77f7f965bc9499a9ae768a296ca5a1f7347d1d2c)
llvm-svn: 326081
diagnostic settings using _Pragma within a macro.
The AST writer had previously been assuming that all diagnostic state
transitions would occur within a FileID corresponding to a file. When a
diagnostic state change occured within a macro, it was unable to form a
location for that state change and would instead corrupt the diagnostic state
of the "root" node (and thus that of the main compilation).
Also introduce a "#pragma clang __debug diag_mapping" debugging utility
that I added to track this issue down.
llvm-svn: 324695
The skipped preprocessor ranges are now serialized in the AST PCH file. This fixes, for example, libclang's clang_getSkippedRanges() returning zero ranges after reparsing a translation unit.
Differential Revision: https://reviews.llvm.org/D20124
llvm-svn: 322503
The patch fixes r321395, that cuased
-Werror=unused-but-set-variable issue for
Diagnosed var on prod build.
From: Evgeny Stupachenko <evstupac@gmail.com>
llvm-svn: 321854
Extend the hashing to functions, which allows detection of function definition
mismatches across modules. This is a re-commit of r320230.
llvm-svn: 321395
The current code would hit an assert in ASTWriter when trying to write
out the filename for a line table entry that didn't have any. Fix this
by allowing the -1 sentinel value to round-trip through serialization.
Differential revision: https://reviews.llvm.org/D40746
llvm-svn: 319707
When mixing PCH and Implicit Modules, missing a header search path
can lead to the implicit built PCM to complaint about not finding its
matching module map.
Instead of adding more magic to implicit modules engine, add a note to
help the user add the appropriate path.
rdar://problem/33388847
llvm-svn: 318503
When a preamble ends in a conditional preprocessor block that is being
skipped, the preprocessor needs to continue skipping that block when
the preamble is used.
This fixes PR34570.
llvm-svn: 317308
This is breaking a build of https://github.com/abseil/abseil-cpp and so
likely not really NFC. Also reverted subsequent r314956/7.
I'll forward reproduction instructions to Richard.
llvm-svn: 315439
In its place, track on the canonical function declaration whether there is a
declaration with a body (and if so, which one). This brings function definition
handling in line with what we do in all other contexts, and is necessary to
allow us to merge declarations within multiple definitions of the same function
(eg, PR33924).
No functionality change intended.
llvm-svn: 314955
This patch relates to: https://reviews.llvm.org/D33666 This adds support
for template parameters to be passed to the address_space attribute.
The main goal is to add further flexibility to the attribute and allow
for it to be used easily with templates.
The main additions are a new type (DependentAddressSpaceType) alongside
its TypeLoc and its mangling. As well as the logic required to support
dependent address spaces which mainly resides in TreeTransform.h and
SemaType.cpp.
llvm-svn: 314649
Introduce a new "export_as" directive for top-level modules, which
indicates that the current module is a "private" module whose symbols
will eventually be exported through the named "public" module. This is
in support of a common pattern in the Darwin ecosystem where a single
public framework is constructed of several private frameworks, with
(currently) header duplication and some support from the linker.
Addresses rdar://problem/34438420.
llvm-svn: 313316
This is a recommit of r312781; in some build configurations
variable names are omitted, so changed the new regression
test accordingly.
llvm-svn: 312794
This adds _Float16 as a source language type, which is a 16-bit floating point
type defined in C11 extension ISO/IEC TS 18661-3.
In follow up patches documentation and more tests will be added.
Differential Revision: https://reviews.llvm.org/D33719
llvm-svn: 312781
This follows the scheme agreed with Nathan Sidwell, which can be found here:
https://gcc.gnu.org/wiki/cxx-modules?action=AttachFile
This will be proposed to the itanium-cxx-abi list once we have some experience
with how well it works; the ABI for this TS should be considered unstable until
it is part of the Itanium C++ ABI.
llvm-svn: 312467
Extend the -fmodule-file option to support the [<name>=]<file> value format.
If the name is omitted, then the old semantics is preserved (the module file
is loaded whether needed or not). If the name is specified, then the mapping
is treated as just another prebuilt module search mechanism, similar to
-fprebuilt-module-path, and the module file is only loaded if actually used
(e.g., via import). With one exception: this mapping also overrides module
file references embedded in other modules (which can be useful if module files
are moved/renamed as often happens during remote compilation).
This override semantics requires some extra work: we now store the module name
in addition to the file name in the serialized AST representation.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D35020
llvm-svn: 312220
Extend the -fmodule-file option to support the [<name>=]<file> value format.
If the name is omitted, then the old semantics is preserved (the module file
is loaded whether needed or not). If the name is specified, then the mapping
is treated as just another prebuilt module search mechanism, similar to
-fprebuilt-module-path, and the module file is only loaded if actually used
(e.g., via import). With one exception: this mapping also overrides module
file references embedded in other modules (which can be useful if module files
are moved/renamed as often happens during remote compilation).
This override semantics requires some extra work: we now store the module name
in addition to the file name in the serialized AST representation.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D35020
llvm-svn: 312105
'#pragma pack (pop)' and suspicious uses of '#pragma pack' in included files
The second recommit (r309106) was reverted because the "non-default #pragma
pack value chages the alignment of struct or union members in the included file"
warning proved to be too aggressive for external projects like Chromium
(https://bugs.chromium.org/p/chromium/issues/detail?id=749197). This recommit
makes the problematic warning a non-default one, and gives it the
-Wpragma-pack-suspicious-include warning option.
The first recommit (r308441) caused a "non-default #pragma pack value might
change the alignment of struct or union members in the included file" warning
in LLVM itself. This recommit tweaks the added warning to avoid warnings for
#includes that don't have any records that are affected by the non-default
alignment. This tweak avoids the previously emitted warning in LLVM.
Original message:
This commit adds a new -Wpragma-pack warning. It warns in the following cases:
- When a translation unit is missing terminating #pragma pack (pop) directives.
- When entering an included file if the current alignment value as determined
by '#pragma pack' directives is different from the default alignment value.
- When leaving an included file that changed the state of the current alignment
value.
rdar://10184173
Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 309386
The warning fires on non-suspicious code in Chromium. Reverting until a
solution is figured out.
> Recommit r308327 2nd time: Add a warning for missing
> '#pragma pack (pop)' and suspicious uses of '#pragma pack' in included files
>
> The first recommit (r308441) caused a "non-default #pragma pack value might
> change the alignment of struct or union members in the included file" warning
> in LLVM itself. This recommit tweaks the added warning to avoid warnings for
> #includes that don't have any records that are affected by the non-default
> alignment. This tweak avoids the previously emitted warning in LLVM.
>
> Original message:
>
> This commit adds a new -Wpragma-pack warning. It warns in the following cases:
>
> - When a translation unit is missing terminating #pragma pack (pop) directives.
> - When entering an included file if the current alignment value as determined
> by '#pragma pack' directives is different from the default alignment value.
> - When leaving an included file that changed the state of the current alignment
> value.
>
> rdar://10184173
>
> Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 309186
'#pragma pack (pop)' and suspicious uses of '#pragma pack' in included files
The first recommit (r308441) caused a "non-default #pragma pack value might
change the alignment of struct or union members in the included file" warning
in LLVM itself. This recommit tweaks the added warning to avoid warnings for
#includes that don't have any records that are affected by the non-default
alignment. This tweak avoids the previously emitted warning in LLVM.
Original message:
This commit adds a new -Wpragma-pack warning. It warns in the following cases:
- When a translation unit is missing terminating #pragma pack (pop) directives.
- When entering an included file if the current alignment value as determined
by '#pragma pack' directives is different from the default alignment value.
- When leaving an included file that changed the state of the current alignment
value.
rdar://10184173
Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 309106
CurrentDir was set as the path of the current module, but that can change as
part of a chain of loaded modules.
When we try to locate a file mentioned in a module that does not exist, we use
a heuristic to look at the relative path between the original location of the
module and the file we look for, and use that relatively to the CurrentDir.
This only works if CurrentDir is the same as the (current) path of the module
file the file was mentioned in; if it is not, we look at the path relatively to
the wrong directory, and can end up reading random unrelated files that happen
to have the same name.
This patch fixes this by using the BaseDirectory of the module file the file
we look for was mentioned in instead of the CurrentDir heuristic.
Differential Revision: https://reviews.llvm.org/D35828
llvm-svn: 308962
This seems to have broken the sanitizer-x86_64-linux buildbot. Reverting until
it's fixed, especially since this landed just before the 5.0 branch.
> This commit adds a new -Wpragma-pack warning. It warns in the following cases:
>
> - When a translation unit is missing terminating #pragma pack (pop) directives.
> - When entering an included file if the current alignment value as determined
> by '#pragma pack' directives is different from the default alignment value.
> - When leaving an included file that changed the state of the current alignment
> value.
>
> rdar://10184173
>
> Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 308455
and suspicious uses of '#pragma pack' in included files
This commit adds a new -Wpragma-pack warning. It warns in the following cases:
- When a translation unit is missing terminating #pragma pack (pop) directives.
- When entering an included file if the current alignment value as determined
by '#pragma pack' directives is different from the default alignment value.
- When leaving an included file that changed the state of the current alignment
value.
rdar://10184173
Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 308441
of '#pragma pack' in included files
This commit adds a new -Wpragma-pack warning. It warns in the following cases:
- When a translation unit is missing terminating #pragma pack (pop) directives.
- When entering an included file if the current alignment value as determined
by '#pragma pack' directives is different from the default alignment value.
- When leaving an included file that changed the state of the current alignment
value.
rdar://10184173
Differential Revision: https://reviews.llvm.org/D35484
llvm-svn: 308327
- Extracted the reading of the tokens out into a separate function.
- Replace 'Argument' with 'Parameter' when referring to the identifiers of the macro definition (as opposed to the supplied arguments - MacroArgs - during the macro invocation).
This is in preparation for submitting patches for review to implement __VA_OPT__ which will otherwise just keep lengthening the HandleDefineDirective function and making it less comprehensible.
I will also directly update some extra clang tooling that is broken by the change from Argument to Parameter.
Hopefully the bots will stay appeased.
Thanks!
llvm-svn: 308190
- Extracted the reading of the tokens out into a separate function.
- Replace 'Argument' with 'Parameter' when referring to the identifiers of the macro definition (as opposed to the supplied arguments - MacroArgs - during the macro invocation).
This is in preparation for submitting patches for review to implement __VA_OPT__ which will otherwise just keep lengthening the HandleDefineDirective function and making it less comprehensible.
Thanks!
llvm-svn: 308157
We use this when running a preprocessor-only action on an AST file in order to
avoid paying the runtime cost of loading the extra information.
llvm-svn: 306760
declarations that are owned but unconditionally visible.
This allows us to set declarations as visible even if they have a local owning
module, without losing information. In turn, that means that our Objective-C
support can keep on incorrectly assuming the "hidden" bit on the declaration is
the whole story with regard to name visibility. This will also be useful once
we support the C++ Modules TS export semantics.
Objective-C name visibility is still incorrect in any case where the "hidden"
bit is not the complete story: for instance, in Objective-C++ the set of
visible categories will be wrong during template instantiation, and with local
submodule visibility enabled it will be wrong when building modules. Fixing that
will require a major overhaul of how visibility is handled for Objective-C (and
particularly for categories).
llvm-svn: 306075
These VarDecl's are static data members of classes. Since the initializers are
also hashed, this also provides checking for default arguments to methods.
llvm-svn: 305543
replay the steps taken to create the AST file with the preprocessor-only action
installed to produce preprocessed output.
This can be used to produce the preprocessed text for an existing .pch or .pcm
file.
llvm-svn: 304726
when saving a module timestamp file
This commit doesn't include a test as it requires a test that reproduces
a file write/close error that couldn't really be constructed artificially.
rdar://31860650
Differential Revision: https://reviews.llvm.org/D33357
llvm-svn: 304538
This patch makes it an error to have a mismatch between the enabled
sanitizers in a CU, and in any module being imported into the CU. Only
mismatches between non-modular sanitizers are treated as errors.
This patch also includes non-modular sanitizers in module hashes, in
order to ensure module rebuilds occur when -fsanitize=X is toggled on
and off for non-modular sanitizers, and to cut down on module rebuilds
when the option is toggled for modular sanitizers.
This fixes a longstanding issue with implicit modules and sanitizers,
which Duncan originally diagnosed.
When building with implicit modules it's possible to hit a scenario
where modules are built without -fsanitize=address, and are subsequently
imported into CUs with -fsanitize=address enabled. This causes strange
failures at runtime. The case Duncan found affects libcxx, since its
vector implementation behaves differently when ASan is enabled.
Implicit module builds should "just work" when -fsanitize=X is toggled
on and off across multiple compiler invocations, which is what this
patch does.
Differential Revision: https://reviews.llvm.org/D32724
llvm-svn: 304463
Previously, a preamble only included #if blocks (and friends like
ifdef) if there was a corresponding #endif before any declaration or
definition. The problem is that any header file that uses include guards
will not have a preamble generated, which can make code-completion very
slow.
To prevent errors about unbalanced preprocessor conditionals in the
preamble, and unbalanced preprocessor conditionals after a preamble
containing unfinished conditionals, the conditional stack is stored
in the pch file.
This fixes PR26045.
Differential Revision: http://reviews.llvm.org/D15994
llvm-svn: 304207
As discussed in D30793, we have some unsafe calls to isConsumerInterestedIn().
This patch implements Richard's suggestion (from the inline comment) that we
should track if we just deserialized an declaration. If we just deserialized,
we can skip the unsafe call because we know it's interesting. If we didn't just
deserialize the declaration, calling isConsumerInterestedIn() should be safe.
We tried to create a test case for this but we were not successful.
Patch by Raphael Isemann (D32499)!
llvm-svn: 303432
The intent for an explicit module build is that the diagnostics produced within
the module are those that were configured when the module was built, not those
that are enabled within a user of the module. This includes diagnostics that
don't actually show up until the module is used (for instance, diagnostics
produced during template instantiation and weird cases like -Wpadded).
We serialized and restored the diagnostic state for individual warning groups,
but previously did not track the state for flags like -Werror and -Weverything,
which are implemented as separate bits rather than as part of the diagnostics
mapping information.
llvm-svn: 301992
If a file has no diagnostic pragmas, we build its diagnostic state lazily, but
in this case we never set up the root state to be the diagnostic state in which
the module was originally built, so the diagnostic flags for files in the
module with no diagnostic pragmas were incorrectly based on the user of the
module rather than the diagnostic state when the module was built.
llvm-svn: 301846
This patch implements the suggestion in D29753 that calling DeclMustBeEmitted in
the middle of deserialization should be avoided and that the actual check should
be deferred until it's safe to do so.
This patch fixes a crash when accessing the invalid redecl chains while trying
to evaluate the value of a const VarDecl that contains a function call.
Patch by Raphael Isemann (D30793)!
llvm-svn: 300110
r293123 started serializing diagnostic pragma state for modules. This
makes the serialization work properly for implicit modules.
An implicit module build (using Clang's internal build system) uses the
same PCM file location for different `-Werror` levels.
E.g., if a TU has `-Werror=format` and tries to load a PCM built without
`-Werror=format`, a new PCM will be built in its place (and the new PCM
should have the same signature, since r297655). In the other direction,
if a TU does not have `-Werror=format` and tries to load a PCM built
with `-Werror=format`, it should "just work".
The idea is to evolve the PCM toward the strictest -Werror flags that
anyone tries.
r293123 started serializing the diagnostic pragma state for each PCM.
Since this encodes the -Werror settings at module-build time, it breaks
the implicit build model.
This commit filters the diagnostic state in order to simulate the
current compilation's diagnostic settings. Firstly, it ignores the
module's serialized first diagnostic state, replacing it with the state
from this compilation's command-line. Secondly, if a pragma warning was
upgraded to error/fatal when generating the PCM (e.g., due to `-Werror`
on the command-line), it checks whether it should still be upgraded in
its current context.
llvm-svn: 300025
Emit the final diagnostic state last to match source order. This also
prepares for a follow-up commit for implicit modules.
There's no real functionaliy change, just a slightly different AST file
format.
llvm-svn: 300024
r299989 fixes the underlying issue by waiting long enough to late parsed
arguments to be processed before doing an calculating the hash.
r298742
[ODRHash] Add error messages for mismatched parameters in methods.
r298754
[ODRHash] Add support for array and decayed types.
llvm-svn: 300001
Matching the function-homing support for modular codegen. Any type
implicitly (implicit template specializations) or explicitly defined in
a module is attached to that module's object file and omitted elsewhere
(only a declaration used if necessary for references).
llvm-svn: 299987
Some decls are created not where they are written, but in other module
files/users (implicit special members and function template implicit
specializations). To correctly identify them, use a bit next to the definition
to track the modular codegen property.
Discussed whether the module file bit could be omitted in favor of
reconstituting from the modular codegen decls list - best guess today is that
the efficiency improvement of not having to deserialize the whole list whenever
any function is queried by a module user is worth it for the small size
increase of this redundant (list + bit-on-def) representation.
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D29901
llvm-svn: 299982
This patch serializes the state of #pragma pack. It preserves the state of the
pragma from a PCH/from modules in a file that uses that PCH/those modules.
rdar://21359084
Differential Revision: https://reviews.llvm.org/D31241
llvm-svn: 299226
Sema holds the current FPOptions which is adjusted by 'pragma STDC
FP_CONTRACT'. This then gets propagated into expression nodes as they are
built.
This encapsulates FPOptions so that this propagation happens opaquely rather
than directly with the fp_contractable on/off bit. This allows controlled
transitioning of fp_contractable to a ternary value (off, on, fast). It will
also allow adding more fast-math flags later.
This is toward moving fp-contraction=fast from an LLVM TargetOption to a
FastMathFlag in order to fix PR25721.
Differential Revision: https://reviews.llvm.org/D31166
llvm-svn: 298877
This restores behavior pre-r230064 since after PCMCache work (r298278)
we don't reload PCMs from disk within the same compiler invocation.
Testcases from r230064 are still left around since they still guarantee
the correct behavior we're expecting.
rdar://problem/19889777
llvm-svn: 298464
This reverts commit r298185, effectively reapplying r298165, after fixing the
new unit tests (PR32338). The memory buffer generator doesn't null-terminate
the MemoryBuffer it creates; this version of the commit informs getMemBuffer
about that to avoid the assert.
Original commit message follows:
----
Clang's internal build system for implicit modules uses lock files to
ensure that after a process writes a PCM it will read the same one back
in (without contention from other -cc1 commands). Since PCMs are read
from disk repeatedly while invalidating, building, and importing, the
lock is not released quickly. Furthermore, the LockFileManager is not
robust in every environment. Other -cc1 commands can stall until
timeout (after about eight minutes).
This commit changes the lock file from being necessary for correctness
to a (possibly dubious) performance hack. The remaining benefit is to
reduce duplicate work in competing -cc1 commands which depend on the
same module. Follow-up commits will change the internal build system to
continue after a timeout, and reduce the timeout. Perhaps we should
reconsider blocking at all.
This also fixes a use-after-free, when one part of a compilation
validates a PCM and starts using it, and another tries to swap out the
PCM for something new.
The PCMCache is a new type called MemoryBufferCache, which saves memory
buffers based on their filename. Its ownership is shared by the
CompilerInstance and ModuleManager.
- The ModuleManager stores PCMs there that it loads from disk, never
touching the disk if the cache is hot.
- When modules fail to validate, they're removed from the cache.
- When a CompilerInstance is spawned to build a new module, each
already-loaded PCM is assumed to be valid, and is frozen to avoid
the use-after-free.
- Any newly-built module is written directly to the cache to avoid the
round-trip to the filesystem, making lock files unnecessary for
correctness.
Original patch by Manman Ren; most testcases by Adrian Prantl!
llvm-svn: 298278
Clang's internal build system for implicit modules uses lock files to
ensure that after a process writes a PCM it will read the same one back
in (without contention from other -cc1 commands). Since PCMs are read
from disk repeatedly while invalidating, building, and importing, the
lock is not released quickly. Furthermore, the LockFileManager is not
robust in every environment. Other -cc1 commands can stall until
timeout (after about eight minutes).
This commit changes the lock file from being necessary for correctness
to a (possibly dubious) performance hack. The remaining benefit is to
reduce duplicate work in competing -cc1 commands which depend on the
same module. Follow-up commits will change the internal build system to
continue after a timeout, and reduce the timeout. Perhaps we should
reconsider blocking at all.
This also fixes a use-after-free, when one part of a compilation
validates a PCM and starts using it, and another tries to swap out the
PCM for something new.
The PCMCache is a new type called MemoryBufferCache, which saves memory
buffers based on their filename. Its ownership is shared by the
CompilerInstance and ModuleManager.
- The ModuleManager stores PCMs there that it loads from disk, never
touching the disk if the cache is hot.
- When modules fail to validate, they're removed from the cache.
- When a CompilerInstance is spawned to build a new module, each
already-loaded PCM is assumed to be valid, and is frozen to avoid
the use-after-free.
- Any newly-built module is written directly to the cache to avoid the
round-trip to the filesystem, making lock files unnecessary for
correctness.
Original patch by Manman Ren; most testcases by Adrian Prantl!
llvm-svn: 298165
Since bitcode uses VBR encoding, large numbers are more expensive than
small ones. Instead of emitting a UINT_MAX sentinel after each sequence
of state-change pairs, emit the size of the sequence as a prefix.
This should have no functionality change besides saving bits from the
encoding.
llvm-svn: 297770
Change ASTFileSignature from a random 32-bit number to the hash of the
PCM content.
- Move definition ASTFileSignature to Basic/Module.h so Module and
ASTSourceDescriptor can use it.
- Change the signature from uint64_t to std::array<uint32_t,5>.
- Stop using (saving/reading) the size and modification time of PCM
files when there is a valid SIGNATURE.
- Add UNHASHED_CONTROL_BLOCK, and use it to store the SIGNATURE record
and other records that shouldn't affect the hash. Because implicit
modules reuses the same file for multiple levels of -Werror, this
includes DIAGNOSTIC_OPTIONS and DIAG_PRAGMA_MAPPINGS.
This helps to solve a PCH + implicit Modules dependency issue: PCH files
are handled by the external build system, whereas implicit modules are
handled by internal compiler build system. This prevents invalidating a
PCH when the compiler overwrites a PCM file with the same content
(modulo the diagnostic differences).
Design and original patch by Manman Ren!
llvm-svn: 297655
Now print diagnostics for static, virtual, inline, volatile, and const
differences in methods. Also use DeclarationName instead of IdentifierInfo
for additional robustness in diagnostic printing.
llvm-svn: 296932
When we are deciding whether we are creating a PCH or a module, we would
check if the ModuleMgr had any elements to switch into PCH mode.
However, when creating a module, the size may be 1. This would result
in us going down the wrong path.
This was found by cross-compiling the swift standard library. Use the
PCH chain length instead to identify the PCH mode.
Unfortunately, I have not yet been able to create a simple test case for
this, but have verified that this fixes the swift standard library
construction.
Thanks to Adrian Prantl for help and discussions with this change!
llvm-svn: 296769
IdentifierInfo is hashed based on the stored string. FieldDecl versus other
Decl is now detected, as well as differently named fields.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 295911
Add support for static_cast in classes. Add pointer-independent profiling for
Stmt's, sharing most of the logic with Stmt::Profile. This is the first of the
deep sub-Decl diffing for error messages.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 295890
Add the basics for the ODRHash class, which will only process Decl's from
a whitelist, which currently only has AccessSpecDecl. Different access
specifiers in merged classes can now be detected.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 295800
If we never need to map any ID within the module to its global ID, we don't
need the module offset map. If a compilation transitively depends on lots of
unused module files, this can result in a modest performance improvement.
llvm-svn: 295517
A slightly weaker form of ODR checking than previous attempts, but hopefully
won't break the modules build bot. Future work will be needed to catch all
cases.
When objects are imported for modules, there is a chance that a name collision
will cause an ODR violation. Previously, only a small number of such
violations were detected. This patch provides a stronger check based on
AST nodes.
The information needed to uniquely identify an object is taken from the AST and
put into a one-dimensional byte stream. This stream is then hashed to give
a value to represent the object, which is stored with the other object data
in the module.
When modules are loaded, and Decl's are merged, the hash values of the two
Decl's are compared. Only Decl's with matched hash values will be merged.
Mismatch hashes will generate a module error, and if possible, point to the
first difference between the two objects.
The transform from AST to byte stream is a modified depth first algorithm.
Due to references between some AST nodes, a pure depth first algorithm could
generate loops. For Stmt nodes, a straight depth first processing occurs.
For Type and Decl nodes, they are replaced with an index number and only on
first visit will these nodes be processed. As an optimization, boolean
values are saved and stored together in reverse order at the end of the
byte stream to lower the ammount of data that needs to be hashed.
Compile time impact was measured at 1.5-2.0% during module building, and
negligible during builds without module building.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 295421
Removed ndrange_t as Clang builtin type and added
as a struct type in the OpenCL header.
Use type name to do the Sema checking in enqueue_kernel
and modify IR generation accordingly.
Review: D28058
Patch by Dmitry Borisenkov!
llvm-svn: 295311
Recommit r293585 that was reverted in r293611 with new fixes. The previous
issue was determined to be an overly aggressive AST visitor from forward
declared objects. The visitor will now only deeply visit certain Decl's and
only do a shallow information extraction from all other Decl's.
When objects are imported for modules, there is a chance that a name collision
will cause an ODR violation. Previously, only a small number of such
violations were detected. This patch provides a stronger check based on
AST nodes.
The information needed to uniquely identify an object is taken from the AST and
put into a one-dimensional byte stream. This stream is then hashed to give
a value to represent the object, which is stored with the other object data
in the module.
When modules are loaded, and Decl's are merged, the hash values of the two
Decl's are compared. Only Decl's with matched hash values will be merged.
Mismatch hashes will generate a module error, and if possible, point to the
first difference between the two objects.
The transform from AST to byte stream is a modified depth first algorithm.
Due to references between some AST nodes, a pure depth first algorithm could
generate loops. For Stmt nodes, a straight depth first processing occurs.
For Type and Decl nodes, they are replaced with an index number and only on
first visit will these nodes be processed. As an optimization, boolean
values are saved and stored together in reverse order at the end of the
byte stream to lower the ammount of data that needs to be hashed.
Compile time impact was measured at 1.5-2.0% during module building, and
negligible during builds without module building.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 295284
We model deduction-guides as functions with a new kind of name that identifies
the template whose deduction they guide; the bulk of this patch is adding the
new name kind. This gives us a clean way to attach an extensible list of guides
to a class template in a way that doesn't require any special handling in AST
files etc (and we're going to need these functions we come to performing
deduction).
llvm-svn: 294266
We're seeing what we believe are false positives. (It's hard to tell with the
available diagnostics, and I'm not sure how to reduce them yet).
I'll send Richard reproduction details offline.
djasper/chandlerc suggested this should be a warning for now, to make rolling it
out feasible.
llvm-svn: 293611
When objects are imported for modules, there is a chance that a name collision
will cause an ODR violation. Previously, only a small number of such
violations were detected. This patch provides a stronger check based on
AST nodes.
The information needed to uniquely identify an object is taked from the AST and
put into a one-dimensional byte stream. This stream is then hashed to give
a value to represent the object, which is stored with the other object data
in the module.
When modules are loaded, and Decl's are merged, the hash values of the two
Decl's are compared. Only Decl's with matched hash values will be merged.
Mismatch hashes will generate a module error, and if possible, point to the
first difference between the two objects.
The transform from AST to byte stream is a modified depth first algorithm.
Due to references between some AST nodes, a pure depth first algorithm could
generate loops. For Stmt nodes, a straight depth first processing occurs.
For Type and Decl nodes, they are replaced with an index number and only on
first visit will these nodes be processed. As an optimization, boolean
values are saved and stored together in reverse order at the end of the
byte stream to lower the ammount of data that needs to be hashed.
Compile time impact was measured at 1.5-2.0% during module building, and
negligible during builds without module building.
Differential Revision: https://reviews.llvm.org/D21675
llvm-svn: 293585
First pass at generating weak definitions of inline functions from module files
(& skipping (-O0) or emitting available_externally (optimizations)
definitions where those modules are used).
External functions defined in modules are emitted into the modular
object file as well (this may turn an existing ODR violation (if that
module were imported into multiple translations) into valid/linkable
code).
Internal symbols (static functions, for example) are not correctly
supported yet. The symbol will be produced, internal, in the modular
object - unreferenceable from the users.
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D28845
llvm-svn: 293456
ModuleManager::removeModules always deletes a tail of the
ModuleManager::Chain. Change the API to enforce that so that we can
simplify the code inside.
There's no real functionality change, although there's a slight
performance hack to loop to the First deleted module instead of the
final module in the chain (skipping the about-to-be-deleted tail).
Also document something suspicious: we fail to clean deleted modules out
of ModuleFile::Imports.
llvm-svn: 293398
Hide the pointer indirection in ModuleManager::begin, ModuleManager::end,
ModuleManager::rbegin, and ModuleManager::rend. Besides tidying up the call
sites, this is preparation for making ownership of ModuleFile explicit.
llvm-svn: 293394
This change adds a new type node, DeducedTemplateSpecializationType, to
represent a type template name that has been used as a type. This is modeled
around AutoType, and shares a common base class for representing a deduced
placeholder type.
We allow deduced class template types in a few more places than the standard
does: in conditions and for-range-declarators, and in new-type-ids. This is
consistent with GCC and with discussion on the core reflector. This patch
does not yet support deduced class template types being named in typename
specifiers.
llvm-svn: 293207
Rather than storing a single flat list of SourceLocations where the diagnostic
state changes (in source order), we now store a separate list for each FileID
in which there is a diagnostic state transition. (State for other files is
built and cached lazily, on demand.) This has two consequences:
1) We can now sensibly support modules, and properly track the diagnostic state
for modular headers (this matters when, for instance, triggering instantiation
of a template defined within a module triggers diagnostics).
2) It's much faster than the old approach, since we can now just do a binary
search on the offsets within the FileID rather than needing to call
isBeforeInTranslationUnit to determine source order (which is surprisingly
slow). For some pathological (but real world) files, this reduces total
compilation time by more than 10%.
For now, the diagnostic state points for modules are loaded eagerly. It seems
feasible to defer this until diagnostic state information for one of the
module's files is needed, but that's not part of this patch.
llvm-svn: 293123
Summary:
Add a callback from ASTReader to DeserializationListener when the former
reads an IMPORTED_MODULES block. This supports Swift in using PCH for
bridging headers.
Reviewers: doug.gregor, manmanren, bruno
Reviewed By: manmanren
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28779
llvm-svn: 292436
D28684 changed llvm::zlib to return Error instead of Status.
It was accepted and committed in r292214, but then reverted in r292217
because I missed that clang code also needs to be updated.
Patch do that.
D28684 recommitted again as r292226
Differential revision: https://reviews.llvm.org/D28807
llvm-svn: 292227
Summary:
We do not currently track the source locations for exception specifications such
that their source range can be queried through the AST. This leads to trying to
write more complex code to determine the source range for uses like FixItHints
(see D18575 for an example). In addition to use within tools like clang-tidy, I
think this information may become more important to track as exception
specifications become more integrated into the type system.
Patch by Don Hinton.
Reviewers: rsmith
Subscribers: malcolm.parsons, sbarzowski, alexfh, hintonda, cfe-commits
Differential Revision: https://reviews.llvm.org/D20428
llvm-svn: 291771
Summary:
For ASTDeclReader and ASTStmtReader, every parameter "unsigned &Idx" ultimately
comes from a variable that is defined on the stack, next to the RecordData. This
change moves that index into the ASTRecordReader.
TypeLocReader cannot be transitioned, due to TableGen-generated code which calls
ASTReader::GetTypeSourceInfo.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27836
llvm-svn: 290217
`RawComments` are sorted by comparing underlying `SourceLocation`'s. This is
done by comparing `FileID` and `Offset`; when the `FileID` is the same it means
the locations are within the same TU and the `Offset` is used.
FileID, from the source code: "A mostly-opaque identifier, where 0 is
"invalid", >0 is this module, and <-1 is something loaded from another
module.". That said, when de-serializing SourceLocations, FileID's from
RawComments loaded from other modules get negative IDs where previously they
were positive. This makes imported RawComments unsorted, leading to a wrong
merge with other comments from the current TU. Fix that by sorting RawComments
properly after de-serialization and before merge.
This fixes an assertion in `ASTContext::getRawCommentForDeclNoCache`,
which fires only in a debug build of clang.
Differential Revision: https://reviews.llvm.org/D27546
rdar://problem/29287314
llvm-svn: 290134
Added a map to associate types and declarations with extensions.
Refactored existing diagnostic for disabled types associated with extensions and extended it to declarations for generic situation.
Fixed some bugs for types associated with extensions.
Allow users to use pragma to declare types and functions for supported extensions, e.g.
#pragma OPENCL EXTENSION the_new_extension_name : begin
// declare types and functions associated with the extension here
#pragma OPENCL EXTENSION the_new_extension_name : end
Differential Revision: https://reviews.llvm.org/D21698
llvm-svn: 289979
Summary:
When reading an ASTRecord, each RecordData is logically contained within a
single ModuleFile, and global(er) state is contained by a single ASTReader. This
means that any operations that read from a RecordData and reference an ASTReader
or a ModuleFile, will always reference the same ASTReader or ModuleFile.
ASTRecordReader groups these together so that parameters don't need to be
duplicated ad infinitum. Most uses of the Idx variable seem to be redunant
aliases as well, but I'll leave that for now.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27784
llvm-svn: 289870
copy constructors of classes with array members, instead using
ArrayInitLoopExpr to represent the initialization loop.
This exposed a bug in the static analyzer where it was unable to differentiate
between zero-initialized and unknown array values, which has also been fixed
here.
llvm-svn: 289618
Summary:
The Swift frontend is acquiring the ability to load non-module PCH files containing
bridging definitions from C/ObjC. As part of this work, it needs to know which submodules
were imported by a PCH in order to wrap them in local Swift modules. This information
is collected by ASTReader::ReadAST in a local vector, but is currently kept private.
The change here is just to make the type of the vector elements public, and provide
an optional out-parameter to the ReadAST method to provide the vector's contents to
a caller after a successful read.
Reviewers: manmanren, rsmith, doug.gregor
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27580
llvm-svn: 289276
PCH files store the macro history for a given macro, and the whole history list
for one identifier is given to the Preprocessor at once via
Preprocessor::setLoadedMacroDirective(). This contained an assert that no macro
history exists yet for that identifier. That's usually true, but it's not true
for builtin macros, which are created in Preprocessor() before flags and pchs
are processed. Luckily, ASTWriter stops writing macro history lists at builtins
(see shouldIgnoreMacro() in ASTWriter.cpp), so the head of the history list was
missing for builtin macros. So make the assert weaker, and splice the history
list to the existing single define for builtins.
https://reviews.llvm.org/D27545
llvm-svn: 289228
This adds the access qualifier to the Pipe Type, rather than using a class
hierarchy.
It also fixes mergeTypes for Pipes, by disallowing merges. Only identical
pipe types can be merged. The test case in invalid-pipes-cl2.0.cl is added
to check that.
llvm-svn: 288332
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106630.html
Move block info block state to a new class, BitstreamBlockInfo.
Clients may set the block info for a particular cursor with the
BitstreamCursor::setBlockInfo() method.
At this point BitstreamReader is not much more than a container for an
ArrayRef<uint8_t>, so remove it and replace all uses with direct uses
of memory buffers.
Differential Revision: https://reviews.llvm.org/D26259
llvm-svn: 286207
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106595.html
This change also fixes an API oddity where BitstreamCursor::Read() would
return zero for the first read past the end of the bitstream, but would
report_fatal_error for subsequent reads. Now we always report_fatal_error
for all reads past the end. Updated clients to check for the end of the
bitstream before reading from it.
I also needed to add padding to the invalid bitcode tests in
test/Bitcode/. This is because the streaming interface was not checking that
the file size is a multiple of 4.
Differential Revision: https://reviews.llvm.org/D26219
llvm-svn: 285773
This reverts commit r284176. It still marks some modules as invisible
that should be visible. Will follow up with the author with a test case.
llvm-svn: 284382
compiles without -fmodules-local-submodule-visibility. Original commit message:
[modules] When merging one definition into another, propagate the list of
re-exporting modules from the discarded definition to the retained definition.
llvm-svn: 284176
Summary:
This is possible now that MapVector supports move-only values.
Depends on D25404.
Reviewers: timshen
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25405
llvm-svn: 283766
Summary:
These cause us to consider all functions in-between to be __host__
__device__.
You can nest these pragmas; you just can't have more 'end's than
'begin's.
Reviewers: rsmith
Subscribers: tra, jhen, cfe-commits
Differential Revision: https://reviews.llvm.org/D24975
llvm-svn: 283677
We also need to add ObjCTypeParamTypeLoc. ObjCTypeParamType supports the
representation of "T <protocol>" where T is a type parameter. Before this,
we use TypedefType to represent the type parameter for ObjC.
ObjCTypeParamType has "ObjCTypeParamDecl *OTPDecl" and it extends from
ObjCProtocolQualifiers. It is a non-canonical type and is canonicalized
to the underlying type with the protocol qualifiers.
rdar://24619481
rdar://25060179
Differential Revision: http://reviews.llvm.org/D23079
llvm-svn: 281355
There is a bug causing pch to be validated even though -fno-validate-pch is set. This patch fixes it.
ASTReader relies on ASTReaderListener to initialize SuggestedPredefines, which is required for compilations using PCH. Before this change, PCHValidator is the default ASTReaderListener. After this change, when -fno-validate-pch is set, PCHValidator is disabled, but we need a replacement ASTReaderListener to initialize SuggestedPredefines. Class SimpleASTReaderListener is implemented for this purpose.
This change only affects -fno-validate-pch. There is no functional change if -fno-validate-pch is not set.
If -fno-validate-pch is not set, conflicts in predefined macros between pch and current compiler instance causes error.
If -fno-validate-pch is set, predefine macros in current compiler override those in pch so that compilation can continue.
Differential Revision: https://reviews.llvm.org/D24054
llvm-svn: 280842
In this mode, there is no need to load any module map and the programmer can
simply use "@import" syntax to load the module directly from a prebuilt
module path. When loading from prebuilt module path, we don't support
rebuilding of the module files and we ignore compatible configuration
mismatches.
rdar://27290316
Differential Revision: http://reviews.llvm.org/D23125
llvm-svn: 279096
With PCH+Module, sometimes compiler gives a hard error:
Module file ‘<some-file path>.pcm' is out of date and needs to be rebuilt
This happens when we have a pch importing a module and the module gets
overwritten by another compiler instance after we build the pch (one example is
that both compiler instances hash to the same pcm file but use different
diagnostic options). When we try to load the pch later on, the compiler notices
that the imported module is out of date (modification date, size do not match)
but it can't handle this out of date pcm (i.e it does not know how to rebuild
the pch).
This commit introduces a new command line option so for PCH + module, we can
turn on this option and if two compiler instances only differ in diagnostic
options, the latter instance will not invalidate the original pcm.
rdar://26675801
Differential Revision: http://reviews.llvm.org/D22773
llvm-svn: 276769
Processing update records (and loading a module, in general) might trigger
unexpected calls to the ASTWriter (being a mutation listener). Now we have a
mechanism to suppress those calls to the ASTWriter but notify other possible
mutation listeners.
Fixes https://llvm.org/bugs/show_bug.cgi?id=28332
Patch by Cristina Cristescu and me.
Reviewed by Richard Smith (D21800).
llvm-svn: 276473
we first touch any part of that module. Instead, defer them until the first
time that module is (transitively) imported. The initializer step for a module
then recursively initializes modules that its own headers imported.
For example, this avoids running the <iostream> global initializer in programs
that don't actually use iostreams, but do use other parts of the standard
library.
llvm-svn: 276159
Summary:
Space for storing the //constraint-expression// of the
//requires-clause// associated with a `TemplateParameterList` is
arranged by taking a bit out of the `NumParams` field for the purpose
of determining whether there is a //requires-clause// or not, and by
adding to the trailing objects tied to the `TemplateParameterList`. An
accessor is provided.
An appropriate argument is supplied to `TemplateParameterList::Create`
at the various call sites.
Serialization changes will addressed as the Concepts implementation
becomes more solid.
Drive-by fix:
This change also replaces the custom
`FixedSizeTemplateParameterListStorage` implementation with one that
follows the interface provided by `llvm::TrailingObjects`.
Reviewers: aaron.ballman, faisalv, rsmith
Subscribers: cfe-commits, nwilson
Differential Revision: https://reviews.llvm.org/D19322
llvm-svn: 276069
passed on the command line but never actually used. We consider a (top-level)
module to be used if any part of it is imported, either by the current
translation unit, or by any part of a top-level module that is itself used.
(Put another way, a module is used if an implicit modules build would have
loaded its .pcm file.)
llvm-svn: 275481
On Linux, if the timestamp of a header file, included in the pch, is modified, then including the pch without regenerating it causes a fatal error, which is reasonable.
On Windows the check is ifdefed out, allowing the compilation to continue in a broken state.
The root of the broken state is that, if timestamps dont match, the preprocessor will reparse a header without discarding the pch data.
This leads to "#pragma once" header to be included twice.
The reason behind the ifdefing of the check lacks documentation, and was done 6 years ago.
This change tentatively removes the ifdefing.
First part of patch proposed at:
Differential Revision: http://reviews.llvm.org/D20867
llvm-svn: 275261
This patch adds a __nth_element builtin that allows fetching the n-th type of a
parameter pack with very little compile-time overhead. The patch was inspired by
r252036 and r252115 by David Majnemer, which add a similar __make_integer_seq
builtin for efficiently creating a std::integer_sequence.
Reviewed as D15421. http://reviews.llvm.org/D15421
llvm-svn: 274316
This is essential for iterating across macros properly, which LLDB does when
loading macros from modules. A naiver version of this patch (without the
conditional) caused assertion failures in the testsuite, but this version should
be safe.
Thanks to Ben Langmuir for the refinement that made this work.
llvm-svn: 269554
This patch corresponds to reviews:
http://reviews.llvm.org/D15120http://reviews.llvm.org/D19125
It adds support for the __float128 keyword, literals and target feature to
enable it. Based on the latter of the two aforementioned reviews, this feature
is enabled on Linux on i386/X86 as well as SystemZ.
This is also the second attempt in commiting this feature. The first attempt
did not enable it on required platforms which caused failures when compiling
type_traits with -std=gnu++11.
If you see failures with compiling this header on your platform after this
commit, it is likely that your platform needs to have this feature enabled.
llvm-svn: 268898
object in C. Rather than using the DeclContext (which is very slow because it
triggers us to build a lookup table for the DeclContext), use a separate map
from identifiers to decls for this case, containing only the ones we've
actually deserialized. For convenience, this map is implemented as an
IdentifierResolver.
llvm-svn: 268817
This commit fixes the IdentifierIterator to actually include identifiers
from a PCH or precompiled preamble when there is also a global module
index. This was causing code-completion (outside of C++) and
typo-correction to be missing global identifiers defined in the
PCH/preamble. Typo-correction has been broken since we first started
using the module index, whereas code-completion only started relying on
identifier iterator in r232793.
rdar://problem/25642879
llvm-svn: 268471
a selector, the entry should be complete, containing everything introduced by
that module and all modules it imports.
Before writing out the method pool of a module, we sync up the out of date
selectors by pulling in methods for the selectors, from all modules it imports.
In ReadMethodPool, after pulling in the method pool entry for module A, this
lets us skip the modules that module A imports.
rdar://problem/25900131
llvm-svn: 268091
PCH in a relative location had a redundant relative path on the DWO
filename and the DW_AT_compilation_dir.
This patch fixes this and adds testcases for PCH in the same directory,
in a relative, and an absolute location.
rdar://problem/25537947
llvm-svn: 267740
Since this patch provided support for the __float128 type but disabled it
on all platforms by default, some platforms can't compile type_traits with
-std=gnu++11 since there is a specialization with __float128.
This reverts the patch until D19125 is approved (i.e. we know which platforms
need this support enabled).
llvm-svn: 266460
a table entry in the corresponding decl, store an offset from the current
record to the relevant CXX_BASE_SPECIFIERS record. This results in fewer
indirections and a minor .pcm file size reduction.
llvm-svn: 266266
of a table entry in the corresponding decl, store an offset from the current
record to the relevant CXX_CTOR_INITIALIZERS record. This results in fewer
indirections and a minor .pcm file size reduction.
llvm-svn: 266254
This patch corresponds to review:
http://reviews.llvm.org/D15120
It adds support for the __float128 keyword, literals and a target feature to
enable it. This support is disabled by default on all targets and any target
that has support for this type is free to add it.
Based on feedback that I've received from target maintainers, this appears to
be the right thing for most targets. I have not heard from the maintainers of
X86 which I believe supports this type. I will subsequently investigate the
impact of enabling this on X86.
llvm-svn: 266186
Putting OpenCLImageTypes.def to clangAST library violates layering requirement: "It's not OK for a Basic/ header to include an AST/ header".
This fixes the modules build.
Differential revision: http://reviews.llvm.org/D18954
Reviewers: Richard Smith, Vassil Vassilev.
llvm-svn: 266180
I. Current implementation of images is not conformant to spec in the following points:
1. It makes no distinction with respect to access qualifiers and therefore allows to use images with different access type interchangeably. The following code would compile just fine:
void write_image(write_only image2d_t img);
kernel void foo(read_only image2d_t img) { write_image(img); } // Accepted code
which is disallowed according to s6.13.14.
2. It discards access qualifier on generated code, which leads to generated code for the above example:
call void @write_image(%opencl.image2d_t* %img);
In OpenCL2.0 however we can have different calls into write_image with read_only and wite_only images.
Also generally following compiler steps have no easy way to take different path depending on the image access: linking to the right implementation of image types, performing IR opts and backend codegen differently.
3. Image types are language keywords and can't be redeclared s6.1.9, which can happen currently as they are just typedef names.
4. Default access qualifier read_only is to be added if not provided explicitly.
II. This patch corrects the above points as follows:
1. All images are encapsulated into a separate .def file that is inserted in different points where image handling is required. This avoid a lot of code repetition as all images are handled the same way in the code with no distinction of their exact type.
2. The Cartesian product of image types and image access qualifiers is added to the builtin types. This simplifies a lot handling of access type mismatch as no operations are allowed by default on distinct Builtin types. Also spec intended access qualifier as special type qualifier that are combined with an image type to form a distinct type (see statement above - images can't be created w/o access qualifiers).
3. Improves testing of images in Clang.
Author: Anastasia Stulova
Reviewers: bader, mgrang.
Subscribers: pxli168, pekka.jaaskelainen, yaxunl.
Differential Revision: http://reviews.llvm.org/D17821
llvm-svn: 265783
explicitly provided, and the module map lists a header that does not exist,
unmark the module as 'unavailable' when loading its .pcm file. (Use of the
module might still fail if the relevant headers aren't embedded, but this
behavior is now consistent with how we behave if the module map is not
provided, and with the desired behavior for embedding headers in modules.)
llvm-svn: 264664
bit from the top bit to the bottom bit, so that we don't need 6 VBR6 hunks for
each macro location. Reduces libstdc++ module size by about 1%.
llvm-svn: 264540
non-deterministic diagnostics (and non-deterministic PCH files). Check these
when building a module rather than serializing it; it's not reasonable for a
module's use to be satisfied by a definition in the user of the module.
llvm-svn: 264466
pragma ms_struct has an effect on struct decls, and the effect is serialized
correctly already. But the "is ms_struct currently on" state wasn't before
this change.
This uses the same approach as `pragma clang optimize`: When writing a module,
the state isn't serialized, only when writing a pch file.
llvm-svn: 262539
to allow arbitrary data to be associated with a parameter.
Also, fix a bug where we apparently haven't been serializing
this information for the last N years.
llvm-svn: 262278
If we didn't tell ReadOptionsBlock to allow failures then we can't
assume that the stream is not in the middle of a block if it returns
out-of-date. This was causing a crash when we tried to continue reading.
Also, it's just generally a good idea to early-exit if we're doing
implicit module builds, since we will want to immediately rebuild this
module anyway and there's no reason to waste time continuing after
failure.
rdar://problem/24114938
llvm-svn: 260563
Update the Preprocessor's VisibleModuleSet when typo-correction creates
an implicit module import so that we won't accidentally write an invalid
SourceLocation into the preamble AST. This would later lead to infinite
recursion when loading the preamble AST because we use the value in
ImportLocs to prevent visiting a module twice.
rdar://problem/24440990
llvm-svn: 260543
Per review feedback the name was wrong and it can be used outside
Objective-C.
Unfortunately, making the internal struct visible broke some ASTMatchers
tests that assumed that the first record decl would be from user code,
rather than a builtin type. I'm worried that this will also affect
users' code. So this patch adds a typedef to wrap the internal struct
and only makes the typedef visible to namelookup. This is sufficient to
allow the ASTReader to merge the decls we need without making the struct
itself visible.
rdar://problem/24425801
llvm-svn: 259734
Original message:
Make CF constant string decl visible to name lookup to fix module errors
The return type of the __builtin___*StringMakeConstantString functions
is a pointer to a struct, so we need that struct to be visible to name
lookup so that we will correctly merge multiple declarations of that
type if they come from different modules.
Incidentally, to make this visible to name lookup we need to rename the
type to __NSConstantString, since the real NSConstantString is an
Objective-C interface type. This shouldn't affect anyone outside the
compiler since users of the constant string builtins cast the result
immediately to CFStringRef.
Since this struct type is otherwise implicitly created by the AST
context and cannot access namelookup, we make this a predefined type
and initialize it in Sema.
Note: this issue of builtins that refer to types not visible to name
lookup technically also affects other builtins (e.g. objc_msgSendSuper),
but in all other cases the builtin is a library builtin and the issue
goes away if you include the library that defines the types it uses,
unlike for these constant string builtins.
rdar://problem/24425801
llvm-svn: 259721
The return type of the __builtin___*StringMakeConstantString functions
is a pointer to a struct, so we need that struct to be visible to name
lookup so that we will correctly merge multiple declarations of that
type if they come from different modules.
Incidentally, to make this visible to name lookup we need to rename the
type to __NSConstantString, since the real NSConstantString is an
Objective-C interface type. This shouldn't affect anyone outside the
compiler since users of the constant string builtins cast the result
immediately to CFStringRef.
Since this struct type is otherwise implicitly created by the AST
context and cannot access namelookup, we make this a predefined type
and initialize it in Sema.
Note: this issue of builtins that refer to types not visible to name
lookup technically also affects other builtins (e.g. objc_msgSendSuper),
but in all other cases the builtin is a library builtin and the issue
goes away if you include the library that defines the types it uses,
unlike for these constant string builtins.
rdar://problem/24425801
llvm-svn: 259624
by stripping the path. Follow-up to r258555.
This is safe because only one PCH per CU is currently supported for
module debugging.
rdar://problem/24301262
llvm-svn: 258582
Summary:
Support for OpenCL 2.0 pipe type.
This is a bug-fix version for bader's patch reviews.llvm.org/D14441
Reviewers: pekka.jaaskelainen, Anastasia
Subscribers: bader, Anastasia, cfe-commits
Differential Revision: http://reviews.llvm.org/D15603
llvm-svn: 257254
This patch attempts to fix the regressions identified when the patch was committed initially.
Thanks to Michael Liao for identifying the fix in the offloading metadata generation
related with side effects in evaluation of function arguments.
llvm-svn: 256933
Summary:
In order to offloading work properly two things need to be in place:
- a descriptor with all the offloading information (device entry functions, and global variable) has to be created by the host and registered in the OpenMP offloading runtime library.
- all the device functions need to be emitted for the device and a convention has to be in place so that the runtime library can easily map the host ID of an entry point with the actual function in the device.
This patch adds support for these two things. However, only entry functions are being registered given that 'declare target' directive is not yet implemented.
About offloading descriptor:
The details of the descriptor are explained with more detail in http://goo.gl/L1rnKJ. Basically the descriptor will have fields that specify the number of devices, the pointers to where the device images begin and end (that will be defined by the linker), and also pointers to a the begin and end of table whose entries contain information about a specific entry point. Each entry has the type:
```
struct __tgt_offload_entry{
void *addr;
char *name;
int64_t size;
};
```
and will be implemented in a pre determined (ELF) section `.omp_offloading.entries` with 1-byte alignment, so that when all the objects are linked, the table is in that section with no padding in between entries (will be like a C array). The code generation ensures that all `__tgt_offload_entry` entries are emitted in the same order for both host and device so that the runtime can have the corresponding entries in both host and device in same index of the table, and efficiently implement the mapping.
The resulting descriptor is registered/unregistered with the runtime library using the calls `__tgt_register_lib` and `__tgt_unregister_lib`. The registration is implemented in a high priority global initializer so that the registration happens always before any initializer (that can potentially include target regions) is run.
The driver flag -omptargets= was created to specify a comma separated list of devices the user wants to support so that the new functionality can be exercised. Each device is specified with its triple.
About target codegen:
The target codegen is pretty much straightforward as it reuses completely the logic of the host version for the same target region. The tricky part is to identify the meaningful target regions in the device side. Unlike other programming models, like CUDA, there are no already outlined functions with attributes that mark what should be emitted or not. So, the information on what to emit is passed in the form of metadata in host bc file. This requires a new option to pass the host bc to the device frontend. Then everything is similar to what happens in CUDA: the global declarations emission is intercepted to check to see if it is an "interesting" declaration. The difference is that instead of checking an attribute, the metadata information in checked. Right now, there is only a form of metadata to pass information about the device entry points (target regions). A class `OffloadEntriesInfoManagerTy` was created to manage all the information and queries related with the metadata. The metadata looks like this:
```
!omp_offload.info = !{!0, !1, !2, !3, !4, !5, !6}
!0 = !{i32 0, i32 52, i32 77426347, !"_ZN2S12r1Ei", i32 479, i32 13, i32 4}
!1 = !{i32 0, i32 52, i32 77426347, !"_ZL7fstatici", i32 461, i32 11, i32 5}
!2 = !{i32 0, i32 52, i32 77426347, !"_Z9ftemplateIiET_i", i32 444, i32 11, i32 6}
!3 = !{i32 0, i32 52, i32 77426347, !"_Z3fooi", i32 99, i32 11, i32 0}
!4 = !{i32 0, i32 52, i32 77426347, !"_Z3fooi", i32 272, i32 11, i32 3}
!5 = !{i32 0, i32 52, i32 77426347, !"_Z3fooi", i32 127, i32 11, i32 1}
!6 = !{i32 0, i32 52, i32 77426347, !"_Z3fooi", i32 159, i32 11, i32 2}
```
The fields in each metadata entry are (in sequence):
Entry 1) an ID of the type of metadata - right now only zero is used meaning "OpenMP target region".
Entry 2) a unique ID of the device where the input source file that contain the target region lives.
Entry 3) a unique ID of the file where the input source file that contain the target region lives.
Entry 4) a mangled name of the function that encloses the target region.
Entries 5) and 6) line and column number where the target region was found.
Entry 7) is the order the entry was emitted.
Entry 2) and 3) are required to distinguish files that have the same function name.
Entry 4) is required to distinguish different instances of the same declaration (usually templated ones)
Entries 5) and 6) are required to distinguish the particular target region in body of the function (it is possible that a given target region is not an entry point - if clause can evaluate always to zero - and therefore we need to identify the "interesting" target regions. )
This patch replaces http://reviews.llvm.org/D12306.
Reviewers: ABataev, hfinkel, tra, rjmccall, sfantao
Subscribers: FBrygidyn, piotr.rak, Hahnfeld, cfe-commits
Differential Revision: http://reviews.llvm.org/D12614
llvm-svn: 256842
than reusing the "overridden buffer" mechanism. This will allow us to make
embedded files and overridden files behave differently in future.
llvm-svn: 254121
https://gcc.gnu.org/onlinedocs/gcc/Typeof.html
Differences from the GCC extension:
* __auto_type is also permitted in C++ (but only in places where
it could appear in C), allowing its use in headers that might
be shared across C and C++, or used from C++98
* __auto_type can be combined with a declarator, as with C++ auto
(for instance, "__auto_type *p")
* multiple variables can be declared in a single __auto_type
declaration, with the C++ semantics (the deduced type must be
the same in each case)
This patch also adds a missing restriction on applying typeof to
a bit-field, which GCC has historically rejected in C (due to
lack of clarity as to whether the operand should be promoted).
The same restriction also applies to __auto_type in C (in both
GCC and Clang).
This also fixes PR25449.
Patch by Nicholas Allegra!
llvm-svn: 252690
we can't load that file due to a configuration mismatch, and implicit module
building is disabled, and the user turns off the error-by-default warning for
that situation, then fall back to textual inclusion for the module rather than
giving an error if any of its headers are included.
llvm-svn: 252114
This new builtin template allows for incredibly fast instantiations of
templates like std::integer_sequence.
Performance numbers follow:
My work station has 64 GB of ram + 20 Xeon Cores at 2.8 GHz.
__make_integer_seq<std::integer_sequence, int, 90000> takes 0.25
seconds.
std::make_integer_sequence<int, 90000> takes unbound time, it is still
running. Clang is consuming gigabytes of memory.
Differential Revision: http://reviews.llvm.org/D13786
llvm-svn: 252036
Introduce the notion of a module file extension, which introduces
additional information into a module file at the time it is built that
can then be queried when the module file is read. Module file
extensions are identified by a block name (which must be unique to the
extension) and can write any bitstream records into their own
extension block within the module file. When a module file is loaded,
any extension blocks are matched up with module file extension
readers, that are per-module-file and are given access to the input
bitstream.
Note that module file extensions can only be introduced by
programmatic clients that have access to the CompilerInvocation. There
is only one such extension at the moment, which is used for testing
the module file extension harness. As a future direction, one could
imagine allowing the plugin mechanism to introduce new module file
extensions.
llvm-svn: 251955
Use the *current* state of "is-moduleness" rather than the state at
serialization time so that if we read a builtin identifier from a module
that wasn't "interesting" to that module, we will still write it out to
a PCH that imports that module.
Otherwise, we would get mysterious "unknown builtin" errors when using
PCH+modules.
rdar://problem/23287656
llvm-svn: 251565
Summary: It breaks the build for the ASTMatchers
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D13893
llvm-svn: 250827
Summary:
This change adds support for `__builtin_ms_va_list`, a GCC extension for
variadic `ms_abi` functions. The existing `__builtin_va_list` support is
inadequate for this because `va_list` is defined differently in the Win64
ABI vs. the System V/AMD64 ABI.
Depends on D1622.
Reviewers: rsmith, rnk, rjmccall
CC: cfe-commits
Differential Revision: http://reviews.llvm.org/D1623
llvm-svn: 247941
them directly to the control block. These are fairly large, and in a build with
lots of modules / chained PCH, we don't need to read most of them. No
functionality change intended.
llvm-svn: 247055
r246546, with a workaround for an MSVC 2013 miscompile and an MSVC 2015
rejects-valid.
Original commit message:
[modules] Rework serialized DeclContext lookup table management. Instead of
walking the loaded ModuleFiles looking for lookup tables for the context, store
them all in one place, and merge them together if we find we have too many
(currently, more than 4). If we do merge, include the merged form in our
serialized lookup table, so that downstream readers never need to look at our
imports' tables.
This gives a huge performance improvement to builds with very large numbers of
modules (in some cases, more than a 2x speedup was observed).
llvm-svn: 246582
predictable diagnostic experience. The hash-of-DeclID order we were using
before gave different results on Win32 due to a different predefined
declaration of __builtin_va_list.
llvm-svn: 246521
walking the loaded ModuleFiles looking for lookup tables for the context, store
them all in one place, and merge them together if we find we have too many
(currently, more than 4). If we do merge, include the merged form in our
serialized lookup table, so that downstream readers never need to look at our
imports' tables.
This gives a huge performance improvement to builds with very large numbers of
modules (in some cases, more than a 2x speedup was observed).
llvm-svn: 246497
Leonard Chan