Egor Churaev [Fri, 23 Dec 2016 16:11:25 +0000 (16:11 +0000)]
[OpenCL] Align fake address space map with the SPIR target maps.
Summary:
We compile user opencl kernel code with spir triple. But built-ins are written in OpenCL and we compile it with triple x86_64 to be able to use x86 intrinsics. And we need address spaces to match in both cases. So, we change fake address space map in OpenCL for matching with spir.
On CPU address spaces are not really important but we'd like to preserve address space information in order to perform optimizations relying on this info like enhanced alias analysis.
Chandler Carruth [Fri, 23 Dec 2016 05:19:47 +0000 (05:19 +0000)]
Add an assert to catch improperly constructed %diff sequences in
diagnostics and fix one such diagnostic.
Sadly, this assert doesn't catch this bug because we have no tests that
emit this diagnostic! Doh! I'm following up on the commit that
introduces it to get that fixed. Then this assert will help in a more
direct way.
Anton Yartsev [Fri, 23 Dec 2016 03:31:00 +0000 (03:31 +0000)]
Fix for PR15623. The patch eliminates unwanted ProgramState checker data propagation from an operand of the logical operation to operation result.
The patch also simplifies an assume of a constraint of the form: "(exp comparison_op expr) != 0" to true into an assume of "exp comparison_op expr" to true. (And similarly, an assume of the form "(exp comparison_op expr) == 0" to true as an assume of exp comparison_op expr to false.) which improves precision overall.
https://reviews.llvm.org/D22862
Richard Smith [Fri, 23 Dec 2016 02:10:11 +0000 (02:10 +0000)]
Move generation of injected template arguments for a template parameter list
out of an internal function and into ASTContext; this is needed in template
argument deduction for P0522R0.
Richard Smith [Fri, 23 Dec 2016 02:00:24 +0000 (02:00 +0000)]
Only substitute into type of non-type template parameter once, rather than
twice, in finalization of template argument deduction.
This is a re-commit of r290310 (reverted in r290329); the bug found by the
buildbots was fixed in r290399 (we would sometimes build a deduced template
argument with a bogus type).
Richard Smith [Fri, 23 Dec 2016 01:30:39 +0000 (01:30 +0000)]
When merging two deduced non-type template arguments for the same parameter,
fail the merge if the arguments have different types (except if one of them was
deduced from an array bound, in which case take the type from the other).
This is correct because (except in the array bound case) the type of the
template argument in each deduction must match the type of the parameter, so at
least one of the two deduced arguments must have a mismatched type.
This is necessary because we would otherwise lose the type information for the
discarded template argument in the merge, and fail to diagnose the mismatch.
In order to power this, we now properly retain the type of a deduced non-type
template argument deduced from a declaration, rather than giving it the type of
the template parameter; we'll convert it to the template parameter type when
checking the deduced arguments.
Chandler Carruth [Fri, 23 Dec 2016 01:24:49 +0000 (01:24 +0000)]
Cleanup the handling of noinline function attributes, -fno-inline,
-fno-inline-functions, -O0, and optnone.
These were really, really tangled together:
- We used the noinline LLVM attribute for -fno-inline
- But not for -fno-inline-functions (breaking LTO)
- But we did use it for -finline-hint-functions (yay, LTO is happy!)
- But we didn't for -O0 (LTO is sad yet again...)
- We had weird structuring of CodeGenOpts with both an inlining
enumeration and a boolean. They interacted in weird ways and
needlessly.
- A *lot* of set smashing went on with setting these, and then got worse
when we considered optnone and other inlining-effecting attributes.
- A bunch of inline affecting attributes were managed in a completely
different place from -fno-inline.
- Even with -fno-inline we failed to put the LLVM noinline attribute
onto many generated function definitions because they didn't show up
as AST-level functions.
- If you passed -O0 but -finline-functions we would run the normal
inliner pass in LLVM despite it being in the O0 pipeline, which really
doesn't make much sense.
- Lastly, we used things like '-fno-inline' to manipulate the pass
pipeline which forced the pass pipeline to be much more
parameterizable than it really needs to be. Instead we can *just* use
the optimization level to select a pipeline and control the rest via
attributes.
Sadly, this causes a bunch of churn in tests because we don't run the
optimizer in the tests and check the contents of attribute sets. It
would be awesome if attribute sets were a bit more FileCheck friendly,
but oh well.
I think this is a significant improvement and should remove the semantic
need to change what inliner pass we run in order to comply with the
requested inlining semantics by relying completely on attributes. It
also cleans up tho optnone and related handling a bit.
One unfortunate aspect of this is that for generating alwaysinline
routines like those in OpenMP we end up removing noinline and then
adding alwaysinline. I tried a bunch of other approaches, but because we
recompute function attributes from scratch and don't have a declaration
here I couldn't find anything substantially cleaner than this.
Chandler Carruth [Fri, 23 Dec 2016 00:23:01 +0000 (00:23 +0000)]
Make '-disable-llvm-optzns' an alias for '-disable-llvm-passes'.
Much to my surprise, '-disable-llvm-optzns' which I thought was the
magical flag I wanted to get at the raw LLVM IR coming out of Clang
deosn't do that. It still runs some passes over the IR. I don't want
that, I really want the *raw* IR coming out of Clang and I strongly
suspect everyone else using it is in the same camp.
There is actually a flag that does what I want that I didn't know about
called '-disable-llvm-passes'. I suspect many others don't know about it
either. It both does what I want and is much simpler.
This removes the confusing version and makes that spelling of the flag
an alias for '-disable-llvm-passes'. I've also moved everything in Clang
to use the 'passes' spelling as it seems both more accurate (*all* LLVM
passes are disabled, not just optimizations) and much easier to remember
and spell correctly.
This is part of simplifying how Clang drives LLVM to make it cleaner to
wire up to the new pass manager.
Sean Callanan [Thu, 22 Dec 2016 20:03:14 +0000 (20:03 +0000)]
Testbed and skeleton of a new expression parser
Recommitted after formal approval.
LLVM's JIT is now the foundation of dynamic-compilation features for many languages. Clang also has low-level support for dynamic compilation (ASTImporter and ExternalASTSource, notably). How the compiler is set up for dynamic parsing is generally left up to individual clients, for example LLDB's C/C++/Objective-C expression parser and the ROOT project.
Although this arrangement offers external clients the flexibility to implement dynamic features as they see fit, the lack of an in-tree client means that subtle bugs can be introduced that cause regressions in the external clients but aren't caught by tests (or users) until much later. LLDB for example regularly encounters complicated ODR violation scenarios where it is not immediately clear who is at fault.
Other external clients (notably, Cling) rely on similar functionality, and another goal is to break this functionality up into composable parts so that any client can be built easily on top of Clang without requiring extensive additional code.
I propose that the parts required to build a simple expression parser be added to Clang. Initially, I aim to have the following features:
A piece that looks up external declarations from a variety of sources (e.g., from previous dynamic compilations, from modules, or from DWARF) and uses clear conflict resolution rules to reconcile differences, with easily understood errors. This functionality will be supported by in-tree tests.
A piece that works hand in hand with the LLVM JIT to resolve the locations of external declarations so that e.g. variables can be redeclared and (for high-performance applications like DTrace) external variables can be accessed directly from the registers where they reside.
This commit adds a tester that parses a sequence of source files and then uses them as source data for an expression. External references are resolved using an ExternalASTSource that responds to name queries using an ASTImporter. This is the setup that LLDB uses, and the motivating reason for MinimalImport in ASTImporter. When complete, this tester will implement the first of the above goals.
Alexey Bataev [Thu, 22 Dec 2016 19:44:05 +0000 (19:44 +0000)]
[OPENMP] Fix for PR31417: assert failure when compiling trivial openmp
program
Offload related code is not quite ready yet, but some simple examples
must not crash the compiler. Patch fixes the problem in offloading code
with exceptions.
Devin Coughlin [Thu, 22 Dec 2016 17:52:57 +0000 (17:52 +0000)]
[analyzer] Update GTestChecker to tighten API detection
Update the GTestChecker to tighten up the API detection and make it
cleaner in response to post-commit feedback. Also add tests for when
temporary destructors are enabled to make sure we get the expected behavior
when inlining constructors for temporaries.
Artem Dergachev [Thu, 22 Dec 2016 14:48:52 +0000 (14:48 +0000)]
[analyzer] Improve suppress-on-sink behavior in incomplete analyses.
Warnings with suppress-on-sink are discarded during FlushReports when
BugReporter notices that all paths in ExplodedGraph that pass through the
warning eventually run into a sink node.
However, suppress-on-sink fails to filter out false positives when the analysis
terminates too early - by running into analyzer limits, such as block count
limits or graph size limits - and the interruption hits the narrow window
between throwing the leak report and reaching the no-return function call. In
such case the report is there, however suppression-on-sink doesn't work, because
the sink node was never constructed in the incomplete ExplodedGraph.
This patch implements a very partial solution: also suppress reports thrown
against a statement-node that corresponds to a statement that belongs to a
no-return block of the CFG.
[CrashReproducer] Add support for merging -ivfsoverlay
Merge all VFS mapped files inside -ivfsoverlay inputs into the vfs
overlay provided by the crash reproducer. This is the last missing piece
to allow crash reproducers to fully work with user frameworks; when
combined with headermaps, it allows clang to find additional frameworks.
Antonio Maiorano [Thu, 22 Dec 2016 05:10:07 +0000 (05:10 +0000)]
Make FormatStyle.GetStyleOfFile test work on MSVC
Modify getStyle to use vfs::FileSystem::makeAbsolute just like FS.addFile does,
rather than sys::fs::make_absolute. The latter gets the CWD from the platform,
while the former expects it to be set by the client, causing a mismatch when
converting relative paths to absolute.
Sema: print qualified name for overload candidates
Print the fully qualified names for the overload candidates. This makes
it easier to tell what the ambiguity is. Especially if a template
is instantiated after a using namespace, it will not inherit the
namespace where it was declared. The specialization will give a message
about a partial order being ambiguous for the same (unqualified) name,
which does not help identify the failure.
The parameter to ParsePICOpts passed the effective triple and then used
that in a few places and used the actual triple in others. This was
slightly confusing. Rename the parameter to make it more obvious.
This is a recommit of r290149, which was reverted in r290169 due to msan
failures. msan was failing because we were calling
`isMostDerivedAnUnsizedArray` on an invalid designator, which caused us
to read uninitialized memory. To fix this, the logic of the caller of
said function was simplified, and we now have a `!Invalid` assert in
`isMostDerivedAnUnsizedArray`, so we can catch this particular bug more
easily in the future.
Fingers crossed that this patch sticks this time. :)
Original commit message:
This patch does three things:
- Gives us the alloc_size attribute in clang, which lets us infer the
number of bytes handed back to us by malloc/realloc/calloc/any user
functions that act in a similar manner.
- Teaches our constexpr evaluator that evaluating some `const` variables
is OK sometimes. This is why we have a change in
test/SemaCXX/constant-expression-cxx11.cpp and other seemingly
unrelated tests. Richard Smith okay'ed this idea some time ago in
person.
- Uniques some Blocks in CodeGen, which was reviewed separately at
D26410. Lack of uniquing only really shows up as a problem when
combined with our new eagerness in the face of const.
Richard Smith [Wed, 21 Dec 2016 21:42:57 +0000 (21:42 +0000)]
Perform type-checking for a converted constant expression in a template
argument even if the expression is value-dependent (we need to suppress the
final portion of the narrowing check, but the rest of the checking can still be
done eagerly).
This affects template template argument validity and partial ordering under
p0522r0.
Richard Smith [Wed, 21 Dec 2016 01:57:02 +0000 (01:57 +0000)]
Fix defaulted-functions-in-C++98 extension to give the functions the same
effect they would have in C++11. In particular, they do not prevent
value-initialization from performing zero-initialization, nor do they prevent a
struct from being an aggregate.
Richard Smith [Wed, 21 Dec 2016 01:31:56 +0000 (01:31 +0000)]
[c++1z] When initializing a const-qualified class type, don't forget to add on
the requested cv-qualifiers after construction. This usually doesn't matter,
but it does matter within a ?: operator.
Richard Smith [Wed, 21 Dec 2016 01:10:31 +0000 (01:10 +0000)]
Factor out checking of template arguments after deduction into a separate
function. (This change would also allow us to handle default template arguments
in partial specializations if the standard ever permits them.)
Graydon Hoare [Wed, 21 Dec 2016 00:24:39 +0000 (00:24 +0000)]
[modules] Handle modules with nonstandard names in module.private.modulemaps
Summary:
The module system supports accompanying a primary module (say Foo) with
an auxiliary "private" module (defined in an adjacent module.private.modulemap
file) that augments the primary module when associated private headers are
available. The feature is intended to be used to augment the primary
module with a submodule (say Foo.Private), however some users in the wild
are choosing to augment the primary module with an additional top-level module
with a "similar" name (in all cases so far: FooPrivate).
This "works" when a user of the module initially imports a private header,
such as '#import "Foo/something_private.h"' since the Foo import winds up
importing FooPrivate in passing. But if the import is subsequently recorded
in a PCH file, reloading the PCH will fail to validate because of a cross-check
that attempts to find the module.modulemap (or module.private.modulemap) using
HeaderSearch algorithm, applied to the "FooPrivate" name. Since it's stored in
Foo.framework/Modules, not FooPrivate.framework/Modules, the check fails and
the PCH is rejected.
This patch adds a compensatory workaround in the HeaderSearch algorithm
when searching (and failing to find) a module of the form FooPrivate: the
name used to derive filesystem paths is decoupled from the module name
being searched for, and if the initial search fails and the module is
named "FooPrivate", the filesystem search name is altered to remove the
"Private" suffix, and the algorithm is run a second time (still looking for
a module named FooPrivate, but looking in directories derived from Foo).
Accompanying this change is a new warning that triggers when a user loads
a module.private.modulemap that defines a top-level module with a different
name from the top-level module defined in its adjacent module.modulemap.
David L. Jones [Wed, 21 Dec 2016 00:17:49 +0000 (00:17 +0000)]
Store the "current position" index within the ASTRecordReader.
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.
Paul Robinson [Tue, 20 Dec 2016 22:30:44 +0000 (22:30 +0000)]
Make a test use a specific C++ dialect
In stack-reuse-miscompile.cpp, the allocas for the temps come out in
a different order depending on whether the dialect is C++03 or
C++11. Specify C++03 explicitly to avoid depending on the default.
Paul Robinson [Tue, 20 Dec 2016 22:26:11 +0000 (22:26 +0000)]
C++11 test cleanup: nonthrowing destructors
If a dtor has no interesting members, then it ends up being nothrow,
which affects the generated IR. Modify some tests to tolerate this
difference between C++03 and C++11.
Richard Smith [Tue, 20 Dec 2016 21:35:28 +0000 (21:35 +0000)]
[c++1z] P0195R2: Support pack-expansion of using-declarations.
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.
This is a re-commit of r290080 (reverted in r290092) with a fix for a
use-after-lifetime bug.
Alexey Bataev [Tue, 20 Dec 2016 12:10:05 +0000 (12:10 +0000)]
[OPENMP] Fix for PR31428: variable named like directive name modifier
Directive name modifiers in 'if' clause are allowed only for OpenMP 4.5
and higher + in OpenMP 4.5 parsing procedure emits error message if ':'
is not found after directive name modifier.
Chandler Carruth [Tue, 20 Dec 2016 08:28:19 +0000 (08:28 +0000)]
Revert r290149: Add the alloc_size attribute to clang.
This commit fails MSan when running test/CodeGen/object-size.c in
a confusing way. After some discussion with George, it isn't really
clear what is going on here. We can make the MSan failure go away by
testing for the invalid bit, but *why* things are invalid isn't clear.
And yet, other code in the surrounding area is doing precisely this and
testing for invalid.
George is going to take a closer look at this to better understand the
nature of the failure and recommit it, for now backing it out to clean
up MSan builds.
Akira Hatanaka [Tue, 20 Dec 2016 02:11:29 +0000 (02:11 +0000)]
[Parser] Correct typo after lambda capture initializer is parsed.
This patch fixes an assertion that is triggered when RecordLayoutBuilder
tries to compute the size of a field (for capture "name" in the test
case) whose type hasn't been deduced. The patch fixes the bug by
correcting the typo of the capture initializer after the initializer is
parsed and before setting the expression for the annotation token.
- Gives us the alloc_size attribute in clang, which lets us infer the
number of bytes handed back to us by malloc/realloc/calloc/any user
functions that act in a similar manner.
- Teaches our constexpr evaluator that evaluating some `const` variables
is OK sometimes. This is why we have a change in
test/SemaCXX/constant-expression-cxx11.cpp and other seemingly
unrelated tests. Richard Smith okay'ed this idea some time ago in
person.
- Uniques some Blocks in CodeGen, which was reviewed separately at
D26410. Lack of uniquing only really shows up as a problem when
combined with our new eagerness in the face of const.
Richard Smith [Mon, 19 Dec 2016 23:59:34 +0000 (23:59 +0000)]
Fix completely bogus types for some builtins:
* In C++, never create a FunctionNoProtoType for a builtin (fixes C++1z
crasher from r289754).
* Fix type of __sync_synchronize to be a no-parameter function rather than a
varargs function. This matches GCC.
* Fix type of vfprintf to match its actual type. We gave it a wrong type due
to PR4290 (apparently autoconf generates invalid code and expects compilers
to choke it down or it miscompiles the program; the relevant error in clang
was downgraded to a warning in r122744 to fix other occurrences of this
autoconf brokenness, so we don't need this workaround any more).
* Turn off vararg argument checking for __noop, since it's not *really* a
varargs function. Alternatively we could add custom type checking for it
and synthesize parameter types matching the actual arguments in each call,
but that seemed like overkill.
Unfortunately, the analyzer does not model the effect of the constructor
precisely because (1) the copy constructor implementation is missing from the
the header (so it can't be inlined) and (2) the boolean-argument constructor
is constructed into a temporary (so the analyzer decides not to inline it since
it doesn't reliably call temporary destructors right now).
This results in false positives because the analyzer does not realize that the
the assertion must hold along the non-return path.
This commit addresses the false positives by explicitly modeling the effects
of the two un-inlined constructors on the AssertionResult state.
I've added a new package, "apiModeling", for these kinds of checkers that
model APIs but don't emit any diagnostics. I envision all the checkers in
this package always being on by default.
This addresses the false positives reported in PR30936.
Jordan Rose [Mon, 19 Dec 2016 22:35:24 +0000 (22:35 +0000)]
Don't try to emit nullability fix-its within/around macros.
The newly-added notes from r290132 are too noisy even when the fix-it
is valid. For the existing warning from r286521, it's probably the
right decision 95% of the time to put the change outside the macro if
the array is outside the macro and inside otherwise, but I don't want
to overthink it right now.
Devin Coughlin [Mon, 19 Dec 2016 22:23:22 +0000 (22:23 +0000)]
[analyzer] Add sink after construction of temporary with no-return destructor.
The analyzer's CFG currently doesn't have nodes for calls to temporary
destructors. This causes the analyzer to explore infeasible paths in which
a no-return destructor would have stopped exploration and so results in false
positives when no-return destructors are used to implement assertions.
To mitigate these false positives, this patch stops generates a sink after
evaluating a constructor on a temporary object that has a no-return destructor.
This results in a loss of coverage because the time at which the destructor is
called may be after the time of construction (especially for lifetime-extended
temporaries).
`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.
Jordan Rose [Mon, 19 Dec 2016 20:58:20 +0000 (20:58 +0000)]
Add fix-it notes to the nullability consistency warning.
This is especially important for arrays, since no one knows the proper
syntax for putting qualifiers in arrays.
nullability.h:3:26: warning: array parameter is missing a nullability type specifier (_Nonnull, _Nullable, or _Null_unspecified)
void arrayParameter(int x[]);
^
nullability.h:3:26: note: insert '_Nullable' if the array parameter may be null
void arrayParameter(int x[]);
^
_Nullable
nullability.h:3:26: note: insert '_Nonnull' if the array parameter should never be null
void arrayParameter(int x[]);
^
_Nonnull
NAKAMURA Takumi [Mon, 19 Dec 2016 16:50:43 +0000 (16:50 +0000)]
[libclang] Revert part of r290025, "Remove the 'extern "C"' blocks from the implementation files."
mingw32-ld complains missing symbols in exports,
Cannot export clang_findIncludesInFileWithBlock: symbol not defined
Cannot export clang_findReferencesInFileWithBlock: symbol not defined
Cannot export clang_visitChildrenWithBlock: symbol not defined
They are excluded conditionally in header along has_blocks.
We should do either;
1. Exclude also function bodies conditionally, and introduce "optional" exporter.
2. Give dummy function bodies for them.
3. Implement functions w/o blocks.
Daniel Jasper [Mon, 19 Dec 2016 07:26:11 +0000 (07:26 +0000)]
clang-format: Allow "single column" list layout even if that violates the
column limit.
Single-column layout basically means that we format the list with one
element per line. Not doing that when there is a column limit violation
doesn't change the fact that there is an item that doesn't fit within
the column limit.
Richard Smith [Mon, 19 Dec 2016 04:08:53 +0000 (04:08 +0000)]
[c++1z] P0195R2: Support pack-expansion of using-declarations.
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.
Richard Smith [Sun, 18 Dec 2016 21:39:37 +0000 (21:39 +0000)]
Fix some interactions between C++11 and C++14 features and using-declarations:
* a dependent non-type using-declaration within a function template can be
valid, as it can refer to an enumerator, so don't reject it in the template
definition
* we can partially substitute into a dependent using-declaration if it appears
within a (local class in a) generic lambda within a function template, which
means an UnresolvedUsing*Decl doesn't necessarily instantiate to a UsingDecl.
Yaxun Liu [Sun, 18 Dec 2016 07:26:01 +0000 (07:26 +0000)]
Fix a lit test issue exposed by r290056
The test requests a target which supports cl_khr_gl_msaa_sharing since in test/PCH/ocl_types.h
it tries to enable cl_khr_gl_msaa_sharing. Therefore this test fails on targets not supporting
cl_khr_gl_msaa_sharing, e.g. ppc64, etc.
The fix is to add triple spir-unknown-unknown which supports cl_khr_gl_msaa_sharing.
[libclang] Remove the 'extern "C"' blocks from the implementation files.
These are unnecessary, the declarations already carry the 'extern C' property, and if there is mismatch
between declaration and definition then we will get linker errors via libclang.exports.
Devin Coughlin [Sat, 17 Dec 2016 01:08:17 +0000 (01:08 +0000)]
[analyzer] UnixAPIChecker: Don't diagnose for functions in C++ namespaces
Update the UnixAPIChecker to not diagnose for calls to functions that
are declared in C++ namespaces. This avoids false positives when a
namespaced function has the same name as a Unix API.
Sean Callanan [Fri, 16 Dec 2016 23:21:38 +0000 (23:21 +0000)]
Testbed and skeleton of a new expression parser
LLVM's JIT is now the foundation of dynamic-compilation features for many languages. Clang also has low-level support for dynamic compilation (ASTImporter and ExternalASTSource, notably). How the compiler is set up for dynamic parsing is generally left up to individual clients, for example LLDB's C/C++/Objective-C expression parser and the ROOT project.
Although this arrangement offers external clients the flexibility to implement dynamic features as they see fit, the lack of an in-tree client means that subtle bugs can be introduced that cause regressions in the external clients but aren't caught by tests (or users) until much later. LLDB for example regularly encounters complicated ODR violation scenarios where it is not immediately clear who is at fault.
Other external clients (notably, Cling) rely on similar functionality, and another goal is to break this functionality up into composable parts so that any client can be built easily on top of Clang without requiring extensive additional code.
I propose that the parts required to build a simple expression parser be added to Clang. Initially, I aim to have the following features:
- A piece that looks up external declarations from a variety of sources (e.g., from previous dynamic compilations, from modules, or from DWARF) and uses clear conflict resolution rules to reconcile differences, with easily understood errors. This functionality will be supported by in-tree tests.
- A piece that works hand in hand with the LLVM JIT to resolve the locations of external declarations so that e.g. variables can be redeclared and (for high-performance applications like DTrace) external variables can be accessed directly from the registers where they reside.
This commit adds a tester that parses a sequence of source files and then uses them as source data for an expression. External references are resolved using an ExternalASTSource that responds to name queries using an ASTImporter. This is the setup that LLDB uses, and the motivating reason for MinimalImport in ASTImporter. When complete, this tester will implement the first of the above goals.
projects / clang / log