Commit Graph

2627 Commits

Author SHA1 Message Date
Vassil Vassilev ed67a74e02 [modules] Do not report missing definitions of demoted constexpr variable templates.
This is a followup to regression introduced in r284284.

This should fix our libstdc++ modules builds.

https://reviews.llvm.org/D25678

Reviewed by Richard Smith!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284577 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-19 11:19:30 +00:00
Erik Pilkington e276fa8786 Revert r284265 "[Sema] Refactor context checking for availability diagnostics"
This has a bug in it, pointed out by Bob Wilson!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284486 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-18 15:26:43 +00:00
Richard Smith ce58cd720b P0012R1: Make exception specifications be part of the type system. This
implements the bulk of the change (modifying the type system to include
exception specifications), but not all the details just yet.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284337 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-16 17:54:23 +00:00
Richard Smith 5b36200c3d Reinstate r284008 reverted in r284081, with two fixes:
1) Merge and demote variable definitions when we find a redefinition in
MergeVarDecls, not only when we find one in AddInitializerToDecl (we only reach
the second case if it's the addition of the initializer itself that converts an
existing declaration into a definition). 

2) When rebuilding a redeclaration chain for a variable, if we merge two
definitions together, mark the definitions as merged so the retained definition
is made visible whenever the demoted definition would have been.

Original commit message (from r283882):

[modules] PR28752: Do not instantiate variable declarations which are not visible.

Original patch by Vassil Vassilev! Changes listed above are mine.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284284 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-14 21:41:24 +00:00
Erik Pilkington bab2991fda [Sema] Refactor context checking for availability diagnostics
This commit combines a couple of redundant functions that do availability
attribute context checking into a more correct/simpler one.

Differential revision: https://reviews.llvm.org/D25283

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284265 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-14 19:08:01 +00:00
Justin Lebar 75a3d319e9 [CUDA] Allow static variables in __host__ __device__ functions, so long as they're never codegen'ed for device.
Reviewers: tra, rnk

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D25150

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284145 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-13 18:45:17 +00:00
Manman Ren d1494637bb Module: emit initializers for C/ObjC after r276159.
In r276159, we started to defer emitting initializers for VarDecls, but
forgot to add the initializers for non-C++ language.

rdar://28740482


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284142 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-13 18:42:14 +00:00
Richard Smith c2d4c5ae67 Revert r284008. This is us to fail to instantiate static data members in some
cases. I'm working on reducing a testcase.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284081 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 23:29:02 +00:00
Vassil Vassilev 4a6c659a27 Reinstate r283887 and r283882.
Original message:
"[modules] PR28752: Do not instantiate variable declarations which are not visible.

https://reviews.llvm.org/D24508

Patch developed in collaboration with Richard Smith!"


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@284008 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 11:57:08 +00:00
Vassil Vassilev 0fff40d646 Revert r283887 and r283882, until the issue is understood and fixed.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283890 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-11 15:51:06 +00:00
Vassil Vassilev f4e0d7fffa r283882 followup. Don't demote ParmVarDecls. This should fix our module builds.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283887 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-11 15:09:26 +00:00
Vassil Vassilev 079f316340 [modules] PR28752: Do not instantiate variable declarations which are not visible.
https://reviews.llvm.org/D24508

Patch developed in collaboration with Richard Smith!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283882 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-11 13:57:36 +00:00
Richard Smith 48fe699daa Re-commit r283722, reverted in r283750, with a fix for a CUDA-specific use of
past-the-end iterator.

Original commit message:

P0035R4: Semantic analysis and code generation for C++17 overaligned
allocation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283789 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-10 18:54:32 +00:00
Daniel Jasper 2b9a6f788b Revert "P0035R4: Semantic analysis and code generation for C++17 overaligned allocation."
This reverts commit r283722. Breaks:
  Clang.SemaCUDA.device-var-init.cu
  Clang.CodeGenCUDA.device-var-init.cu

http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA-expensive/884/

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283750 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-10 14:13:55 +00:00
Richard Smith 15bd535355 P0035R4: Semantic analysis and code generation for C++17 overaligned
allocation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283722 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-10 06:42:31 +00:00
Serge Pavlov 4fc3da4494 Do not find friend function definitions inside non-instantiated class.
Previously if a file-level function was defined inside befriending
template class, it always was treated as defined. For instance, the code like:
```
  int func(int x);
  template<typename T> class C1 {
    friend int func(int x) { return x; }
  };
  template<typename T> class C2 {
    friend int func(int x) { return x; }
  };
```
could not be compiled due to function redefinition, although not of the templates
is instantiated. Moreover, the body of friend function can contain use of template
parameters, attempt to get definition of such function outside any instantiation
causes compiler abnormal termination.

Other compilers (gcc, icc) follow viewpoint that the body of the function defined
in friend declaration becomes available when corresponding class is instantiated.
This patch implements this viewpoint in clang.

Definitions introduced by friend declarations in template classes are not added
to the redeclaration chain of corresponding function. Only when the template is
instantiated, instantiation of the function definition is placed to the chain.

The fix was made in collaboration with Richard Smith.

This change fixes PR8035, PR17923, PR22307 and PR25848.

Differential Revision: http://reviews.llvm.org/D16989


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283207 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-04 10:11:43 +00:00
Reid Kleckner e58d233abb Factor out a diagnostic kind enum for use in two %select expressions
NFC

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283131 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-03 18:34:23 +00:00
Gor Nishanov 05da52cced [coroutines] Rename driver flag -fcoroutines to -fcoroutines-ts
Summary:
Also makes -fcoroutines_ts to be both a Driver and CC1 flag.

Patch mostly by EricWF.

Reviewers: rnk, cfe-commits, rsmith, EricWF

Subscribers: mehdi_amini

Differential Revision: https://reviews.llvm.org/D25130

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283064 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-02 03:31:58 +00:00
Richard Smith bec0fbe74a P0035R4: add std::align_val_t overloads of operator new/delete in C++17 mode.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@282800 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-29 22:49:46 +00:00
Richard Smith 92f23b6427 [Modules TS] Diagnose 'export' declaration within 'export' declaration.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@282443 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-26 21:27:23 +00:00
Yaxun Liu 13934c8542 [OpenCL] Allow half type kernel argument when cl_khr_fp16 is enabled
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281915 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-19 17:11:22 +00:00
Albert Gutowski 5eb95c4c28 Add some MS aliases for existing intrinsics
Reviewers: thakis, compnerd, majnemer, rsmith, rnk

Subscribers: alexshap, cfe-commits

Differential Revision: https://reviews.llvm.org/D24330


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281540 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-14 21:19:43 +00:00
Artem Belevich 19ed54635a [CUDA] Do not merge CUDA target attributes.
CUDA target attributes are used for function overloading and must not be merged.

This fixes a bug where attributes were inherited during function template
specialization in CUDA and made it impossible for specialized function
to provide its own target attributes.

Differential Revision: https://reviews.llvm.org/D24522

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281406 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 22:16:30 +00:00
Albert Gutowski 1b076bcb9c Reverse commit 281375 (breaks building Chromium)
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281399 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 21:24:51 +00:00
Albert Gutowski c79ec5a5d7 Add some MS aliases for existing intrinsics
Reviewers: thakis, compnerd, majnemer, rsmith, rnk

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24330


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281375 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 19:26:42 +00:00
Nico Weber eb208defa1 [clang-cl] Diagnose duplicate uuids.
This mostly behaves cl.exe's behavior, even though clang-cl is stricter in some
corner cases and more lenient in others (see the included test).

To make the uuid declared previously here diagnostic work correctly, tweak
stripTypeAttributesOffDeclSpec() to keep attributes in the right order.

https://reviews.llvm.org/D24469


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281367 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 18:55:26 +00:00
Nikola Smiljanic 6b9f3606b5 Allow register variables in naked functions.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@281298 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 07:02:02 +00:00
Richard Smith e32e1d11d7 C++ Modules TS: Add parsing and some semantic analysis support for
export-declarations. These don't yet have an effect on name visibility;
we still export everything by default.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280999 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-08 23:14:54 +00:00
Eric Fiselier 89aa3ede8e Implement __attribute__((require_constant_initialization)) for safe static initialization.
Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.

Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.

This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.

```c++
  // -std=c++14
  #define SAFE_STATIC __attribute__((require_constant_initialization)) static
  struct T {
    constexpr T(int) {}
    ~T();
  };
  SAFE_STATIC T x = {42}; // OK.
  SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
  // copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.

Reviewers: majnemer, rsmith, aaron.ballman

Subscribers: jroelofs, cfe-commits

Differential Revision: https://reviews.llvm.org/D23385

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280525 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-02 18:53:31 +00:00
Eric Fiselier f92a8d01c4 Revert r280516 since it contained accidental changes.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280521 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-02 18:43:25 +00:00
Eric Fiselier 85fb4f5d75 Implement __attribute__((require_constant_initialization)) for safe static initialization.
Summary:
This attribute specifies expectations about the initialization of static and
thread local variables. Specifically that the variable has a
[constant initializer](http://en.cppreference.com/w/cpp/language/constant_initialization)
according to the rules of [basic.start.static]. Failure to meet this expectation
will result in an error.

Static objects with constant initializers avoid hard-to-find bugs caused by
the indeterminate order of dynamic initialization. They can also be safely
used by other static constructors across translation units.

This attribute acts as a compile time assertion that the requirements
for constant initialization have been met. Since these requirements change
between dialects and have subtle pitfalls it's important to fail fast instead
of silently falling back on dynamic initialization.

```c++
  // -std=c++14
  #define SAFE_STATIC __attribute__((require_constant_initialization)) static
  struct T {
    constexpr T(int) {}
    ~T();
  };
  SAFE_STATIC T x = {42}; // OK.
  SAFE_STATIC T y = 42; // error: variable does not have a constant initializer
  // copy initialization is not a constant expression on a non-literal type.
```
This attribute can only be applied to objects with static or thread-local storage
duration.

Reviewers: majnemer, rsmith, aaron.ballman

Subscribers: jroelofs, cfe-commits

Differential Revision: https://reviews.llvm.org/D23385

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280516 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-02 18:25:29 +00:00
Richard Smith 7e8dc8a5df When we reach the end of a #include of a header of a local submodule that we
textually included, create an ImportDecl just as we would if we reached a
#include of any other modular header. This is necessary in order to correctly
determine the set of variables to initialize for an imported module.

This should hopefully make the modules selfhost buildbot green again.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280409 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-01 20:15:25 +00:00
Akira Hatanaka 0c1c175147 [Sema] Don't diagnose an array type mismatch when the new or previous
declaration has a dependent type.

This fixes a bug where clang errors out on a valid code.

rdar://problem/28051467

Differential Revision: https://reviews.llvm.org/D24110


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280330 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-01 01:03:21 +00:00
Richard Smith 434bc3478f PR12298 et al: don't recursively instantiate a template specialization from
within the instantiation of that same specialization. This could previously
happen for eagerly-instantiated function templates, variable templates,
exception specifications, default arguments, and a handful of other cases.

We still have an issue here for default template arguments that recursively
make use of themselves and likewise for substitution into the type of a
non-type template parameter, but in those cases we're producing a different
entity each time, so they should instead be caught by the instantiation depth
limit. However, currently we will typically run out of stack before we reach
it. :(


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280190 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-31 02:15:21 +00:00
Richard Smith d605534140 C++ Modules TS: add frontend support for building pcm files from module
interface files. At the moment, all declarations (and no macros) are exported,
and 'export' declarations are not supported yet.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279794 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-26 00:14:38 +00:00
Richard Smith 584334cb10 Fix regression introduced by r279164: only pass definitions as the PatternDef
to DiagnoseUninstantiableTemplate, teach hasVisibleDefinition to correctly
determine whether a function definition is visible, and mark both the function
and the template as visible when merging function template definitions to
provide hasVisibleDefinition with the relevant information.

The change to always pass the right declaration as the PatternDef to
DiagnoseUninstantiableTemplate also caused those checks to happen before other
diagnostics in InstantiateFunctionDefinition, giving worse diagnostics for the
same situations, so I sunk the relevant diagnostics into
DiagnoseUninstantiableTemplate. Those parts of this patch are based on changes
in reviews.llvm.org/D23492 by Vassil Vassilev.


This reinstates r279486, reverted in r279500, with a fix to
DiagnoseUninstantiableTemplate to only mark uninstantiable explicit
instantiation declarations as invalid if we actually diagnosed them. (When we
trigger an explicit instantiation of a class member from an explicit
instantiation declaration for the class, it's OK if there is no corresponding
definition and we certainly don't want to mark the member invalid in that
case.) This previously caused a build failure during bootstrap.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279557 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-23 19:41:39 +00:00
Chandler Carruth 36fa4bbf3f Revert r279486 "Fix regression introduced by r279164"
Build bots seem unhappy and as Richard was leaving he asked me to revert
this for him. Doing so.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279500 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-23 02:00:51 +00:00
Richard Smith e7c9a6c34c Fix regression introduced by r279164: only pass definitions as the PatternDef
to DiagnoseUninstantiableTemplate, teach hasVisibleDefinition to correctly
determine whether a function definition is visible, and mark both the function
and the template as visible when merging function template definitions to
provide hasVisibleDefinition with the relevant information.

The change to always pass the right declaration as the PatternDef to
DiagnoseUninstantiableTemplate also caused those checks to happen before other
diagnostics in InstantiateFunctionDefinition, giving worse diagnostics for the
same situations, so I sunk the relevant diagnostics into
DiagnoseUninstantiableTemplate. Those parts of this patch are based on changes
in reviews.llvm.org/D23492 by Vassil Vassilev.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279486 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-22 22:25:03 +00:00
Richard Smith f76493a344 C++ Modules TS: support parsing the 'module' declaration (including extensions
from p0273r0 approved by EWG). We'll eventually need to handle this from the
lexer as well, in order to disallow preprocessor directives preceding the
module declaration and to support macro import.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279196 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-19 01:43:06 +00:00
Richard Smith ec9187d1cd C++ Modules TS: Add parsing support for module import declaration.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279163 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-18 21:59:42 +00:00
Reid Kleckner b2df6a41f4 [MS] Silence -Wextern-init on const selectany variables
In C, 'extern' is typically used to avoid tentative definitions when
declaring variables in headers, but adding an intializer makes it a
defintion. This is somewhat confusing, so GCC and Clang both warn on it.
In C++, 'extern' is often used to give implictly static 'const'
variables external linkage, so don't warn in that case. If selectany is
present, this might be header code intended for C and C++ inclusion, so
apply the C++ rules.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@279116 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-18 18:45:07 +00:00
Erik Pilkington 1d09f0125a [ObjC] Warn on unguarded use of partial declaration
This commit adds a traversal of the AST after Sema of a function that diagnoses
unguarded references to declarations that are partially available (based on
availability attributes). This traversal is only done when we would otherwise
emit -Wpartial-availability.

This commit is part of a feature I proposed here:
http://lists.llvm.org/pipermail/cfe-dev/2016-July/049851.html

Differential revision: https://reviews.llvm.org/D23003

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278826 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-16 17:44:11 +00:00
Richard Smith d28be6c82c P0217R3: template instantiation support for decomposition declarations.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278458 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-12 01:55:21 +00:00
Richard Smith 1068a78bd3 Remove unused and undesirable reference from BindingDecl to DecompositionDecl.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278448 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-12 00:53:41 +00:00
Richard Smith c52f27b275 P0217R3: Constant expression evaluation for decomposition declarations.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278447 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-12 00:39:32 +00:00
Richard Smith 5f0128122c P0217R3: Perform semantic checks and initialization for the bindings in a
decomposition declaration for arrays, aggregate-like structs, tuple-like
types, and (as an extension) for complex and vector types.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278435 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-11 22:25:46 +00:00
Justin Lebar bd12a41e3d [CUDA] Reject calls to __device__ functions from host variable global initializers.
Reviewers: tra

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D23335

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278196 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-10 01:09:21 +00:00
Serge Pavlov c231913835 Pass information in a record instead of stack. NFC
Functions of Sema that work with building of nested name specifiers have too
many parameters (BuildCXXNestedNameSpecifier already expects 10 arguments).
With this change the information about identifier and its context is packed
into a structure, which is then passes to the semantic functions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@277976 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-08 04:02:15 +00:00
Richard Smith 1a9b9adf6f P0217R3: Parsing support and framework for AST representation of C++1z
decomposition declarations.

There are a couple of things in the wording that seem strange here:
decomposition declarations are permitted at namespace scope (which we partially
support here) and they are permitted as the declaration in a template (which we
reject).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@276492 91177308-0d34-0410-b5e6-96231b3b80d8
2016-07-22 23:36:59 +00:00
Richard Smith 3b75c09ec6 [modules] Don't emit initializers for VarDecls within a module eagerly whenever
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.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@276159 91177308-0d34-0410-b5e6-96231b3b80d8
2016-07-20 19:10:16 +00:00