There are situations when clang knows that the C1 and C2 constructors
or the D1 and D2 destructors are identical. We already optimize some
of these cases, but cannot optimize it when the GlobalValue is
weak_odr.
The problem with weak_odr is that an old TU seeing the same code will
have a C1 and a C2 comdat with the corresponding symbols. We cannot
suddenly start putting the C2 symbol in the C1 comdat as we cannot
guarantee that the linker will not pick a .o with only C1 in it.
The solution implemented by GCC is to expand the ABI to have a comdat
whose name uses a C5/D5 suffix and always has both symbols. That is
what this patch implements.
llvm-svn: 217874
For the following code:
__declspec(dllimport) int f(int x);
int user(int x) {
return f(x);
}
int f(int x) { return 1; }
Clang will drop the dllimport attribute in the AST, but CodeGen would have
already put it on the LLVM::Function, and that would never get updated.
(The same thing happens for global variables.)
This makes Clang check dropped DLL attribute case each time the LLVM object
is referenced.
This isn't perfect, because we will still get it wrong if the function is
never referenced by codegen after the attribute is dropped, but this handles
the common cases and makes us not fail in the verifier.
llvm-svn: 216699
This patch adds the '-fcoverage-mapping' option which
allows clang to generate the coverage mapping information
that can be used to provide code coverage analysis using
the execution counts obtained from the instrumentation
based profiling (-fprofile-instr-generate).
llvm-svn: 214752
It is responsible for generating metadata consumed by sanitizer instrumentation
passes in the backend. Move several methods from CodeGenModule to SanitizerMetadata.
For now the class is stateless, but soon it won't be the case.
Instead of creating globals providing source-level information to ASan, we will create
metadata nodes/strings which will be turned into actual global variables in the
backend (if needed).
No functionality change.
llvm-svn: 214564
they're somehow missing a body. Looks like this was left behind when the loop
was generalized, and it's not been problematic before because without modules,
a used, implicit special member function declaration must be a definition.
This was resulting in us trying to emit a constructor declaration rather than
a definition, and producing a constructor missing its member initializers.
llvm-svn: 214473
Summary:
This change adds description of globals created by UBSan
instrumentation (UBSan handlers, type descriptors, filenames) to
llvm.asan.globals metadata, effectively "blacklisting" them. This can
dramatically decrease the data section in binaries built with UBSan+ASan,
as UBSan tends to create a lot of handlers, and ASan instrumentation
increases the global size to at least 64 bytes.
Test Plan: clang regression test suite
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits, byoungyoung, kcc
Differential Revision: http://reviews.llvm.org/D4575
llvm-svn: 213392
This makes us emit dllexported in-class initialized static data members (which
are treated as definitions in MSVC), even when they're not referenced.
It also makes their special linkage reflected in the GVA linkage instead of
getting massaged in CodeGen.
Differential Revision: http://reviews.llvm.org/D4563
llvm-svn: 213304
Currently ASan instrumentation pass creates a string with global name
for each instrumented global (to include global names in the error report). Global
name is already mangled at this point, and we may not be able to demangle it
at runtime (e.g. there is no __cxa_demangle on Android).
Instead, create a string with fully qualified global name in Clang, and pass it
to ASan instrumentation pass in llvm.asan.globals metadata. If there is no metadata
for some global, ASan will use the original algorithm.
This fixes https://code.google.com/p/address-sanitizer/issues/detail?id=264.
llvm-svn: 212872
Turn llvm::SpecialCaseList into a simple class that parses text files in
a specified format and knows nothing about LLVM IR. Move this class into
LLVMSupport library. Implement two users of this class:
* DFSanABIList in DFSan instrumentation pass.
* SanitizerBlacklist in Clang CodeGen library.
The latter will be modified to use actual source-level information from frontend
(source file names) instead of unstable LLVM IR things (LLVM Module identifier).
Remove dependency edge from ClangCodeGen/ClangDriver to LLVMTransformUtils.
No functionality change.
llvm-svn: 212643
Get rid of cached CodeGenModule::SanOpts, which was used to turn off
sanitizer codegen options if current LLVM Module is blacklisted, and use
plain LangOpts.Sanitize instead.
1) Some codegen decisions (turning TBAA or writable strings on/off)
shouldn't depend on the contents of blacklist.
2) llvm.asan.globals should *always* be created, even if the module
is blacklisted - soon Clang's CodeGen where we read sanitizer
blacklist files, so we should properly report which globals are
blacklisted to the backend.
llvm-svn: 212499
Let's not expose ABI specific minutia inside of CodeGenModule and Type.
Instead, let's abstract it through CXXABI.
This gets rid of:
CodeGenModule::getCompleteObjectLocator,
CodeGenModule::EmitFundamentalTypeDescriptor{s,},
CodeGenModule::getMSTypeDescriptor,
CodeGenModule::getMSCompleteObjectLocator,
CGCXXABI::shouldRTTIBeUnique,
CGCXXABI::classifyRTTIUniqueness.
CGRTTI was *almost* entirely centered around providing Itanium-style
RTTI information. Instead of providing interfaces that only it
consumes, move it to the ItaniumCXXABI implementation file. This allows
it to have access to Itanium-specific implementation details without
providing useless expansion points for the Microsoft ABI side.
Differential Revision: http://reviews.llvm.org/D4261
llvm-svn: 212435
Summary:
Because a global created by GetOrCreateLLVMGlobal() is not finalised until later viz:
extern char a[];
char f(){ return a[5];}
char a[10];
Change MangledDeclNames to use a MapVector rather than a DenseMap so that the
Metadata is output in order of original declaration, so to make deterministic
and improve human readablity.
Differential Revision: http://reviews.llvm.org/D4176
llvm-svn: 212263
See https://code.google.com/p/address-sanitizer/issues/detail?id=299 for the
original feature request.
Introduce llvm.asan.globals metadata, which Clang (or any other frontend)
may use to report extra information about global variables to ASan
instrumentation pass in the backend. This metadata replaces
llvm.asan.dynamically_initialized_globals that was used to detect init-order
bugs. llvm.asan.globals contains the following data for each global:
1) source location (file/line/column info);
2) whether it is dynamically initialized;
3) whether it is blacklisted (shouldn't be instrumented).
Source location data is then emitted in the binary and can be picked up
by ASan runtime in case it needs to print error report involving some global.
For example:
0x... is located 4 bytes to the right of global variable 'C::array' defined in '/path/to/file:17:8' (0x...) of size 40
These source locations are printed even if the binary doesn't have any
debug info.
This is an ABI-breaking change. ASan initialization is renamed to
__asan_init_v4(). Pre-built libraries compiled with older Clang will not work
with the fresh runtime.
llvm-svn: 212188
Improve the warning when building with -fprofile-instr-use and a file
appears not to have been profiled at all. This keys on whether a
function is defined in the main file or not to avoid false negatives
when one includes a header with functions that have been profiled.
llvm-svn: 211760
The backing store of thread local variables is internal for OS X and all
accesses must go through the thread wrapper.
However, individual TUs may have inlined through the thread wrapper.
To fix this, give the thread wrapper functions WeakAnyLinkage. This
prevents them from getting inlined into call-sites.
This fixes PR19989.
llvm-svn: 210632
Add driver and frontend support for the GCC -Wframe-larger-than=bytes warning.
This is the first GCC-compatible backend diagnostic built around LLVM's
reporting feature.
This commit adds infrastructure to perform reverse lookup from mangled names
emitted after LLVM IR generation. We use that to resolve precise locations and
originating AST functions, lambdas or block declarations to produce seamless
codegen-guided diagnostics.
An associated change, StringMap now maintains unique mangled name strings
instead of allocating copies. This is a net memory saving in C++ and a small
hit for C where we no longer reuse IdentifierInfo storage, pending further
optimisation.
llvm-svn: 210293
Share mode code between these functions and re-structure them in a way
which shows how similar they actually are. The latter function works well
with literals of multi-byte chars and does a GlobalVariable name mangling
(if global strings are non-writable).
No functionality change.
llvm-svn: 210212
The only remaining user didn't actually use the non-dynamic storage facility
this class provides.
The std::string is transitional and likely to be StringRefized shortly.
llvm-svn: 210058
Clang knows about the sanitizer blacklist and it makes no sense to
add global to the list of llvm.asan.dynamically_initialized_globals if it
will be blacklisted in the instrumentation pass anyway. Instead, we should
do as much blacklisting as possible (if not all) in the frontend.
llvm-svn: 209789
MSVC doesn't export these functions, so trying to import them doesnt' work.
Also, don't let any dll attributes on the CXXDestructorDecl influence the
thunk's linkage -- they should always be linkonce_odr.
This takes care of the FIXME's for this in Nico's tests.
Differential Revision: http://reviews.llvm.org/D3930
llvm-svn: 209706
Initializers of global data that can appear multiple TUs (static data
members of class templates or __declspec(selectany) data) are now in a
comdat group keyed on the global variable being initialized. On
non-Windows platforms, this is a code size and startup time
optimization. On Windows, this is necessary for ABI compatibility with
MSVC.
Fixes PR16959.
Reviewers: rsmith
Differential Revision: http://reviews.llvm.org/D3811
llvm-svn: 209555
This was fairly broken. For example,
@__dso_handle would or would not get an unnamed_addr depending on how many
global destructors were used in a translation unit.
The consensus was that not every runtime variable is unnamed_addr and that
__dso_handle handle should not be, so just don't add unnamed_addr in
CreateRuntimeVariable.
llvm-svn: 209484
behavior on mismatch. The AutoUpgrader will drop incompatible debug info
any way and also emit a warning diagnostic for it.
rdar://problem/16926122
llvm-svn: 209182
Now that llvm cannot represent alias cycles, we have to diagnose erros just
before trying to close the cycle. This degrades the errors a bit. The real
solution is what it was before: if we want to provide good errors for these
cases, we have to be able to find a clang level decl given a mangled name
and produce the error from Sema.
llvm-svn: 209008
Summary:
Previously, we would generate a single name for all reference
temporaries and allow LLVM to rename them for us. Instead, number the
reference temporaries as we build them in Sema.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D3554
llvm-svn: 207776
Summary:
A reference temporary should inherit the linkage of the variable it
initializes. Otherwise, we may hit cases where a reference temporary
wouldn't have the same value in all translation units.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D3515
llvm-svn: 207451
Almost all linkage calculation for VarDecls occured inside of
GetLLVMLinkageVarDefinition except for static data members. Centralize
the logic so that it can be more readily reused.
No functionality change.
llvm-svn: 207241
It turns out that linkage and visibility have rather similar logic for
both functions and non-variable globals. Split the calculation out so
that both sides may share this code.
No functionality change.
llvm-svn: 207239
Update clang to use the InstrProfReader from LLVM to read
instrumentation based profile data. This also switches us from the
naive text format to the binary format, since that's what's
implemented in the reader.
llvm-svn: 206658
This adds a warning that triggers when profile data doesn't match for
the source that's being compiled with -fprofile-instr-use=. This fires
only once per translation unit, as warning on every mismatched
function would be quite noisy.
llvm-svn: 206322
Emitting the PGO initialization in EmitGlobalFunctionDefinition is
inefficient, since this only has an effect once per module. We move
this to Release() with the rest of the once-per-module logic.
llvm-svn: 205977
Summary:
MSVC always emits inline functions marked with the extern storage class
specifier. The result is something similar to the opposite of
__attribute__((gnu_inline)).
This extension is also available in C.
This fixes PR19264.
Reviewers: rnk, rsmith
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3207
llvm-svn: 205485
Clang implements the part of the ARM ABI saying that certain functions
(e.g., constructors and destructors) return "this", but Apple's version of
gcc and llvm-gcc did not. The libstdc++ dylib on iOS 5 was built with
llvm-gcc, which means that clang cannot safely assume that code from the C++
runtime will correctly follow the ABI. It is also possible to run into this
problem when linking with other libraries built with gcc or llvm-gcc. Even
though there is no way to reliably detect that situation, it is most likely
to come up when targeting older versions of iOS. Disabling the optimization
for any code targeting iOS 5 solves the libstdc++ problem and has a reasonably
good chance of fixing the issue for other older libraries as well.
<rdar://problem/16377159>
llvm-svn: 205272
This adds Clang support for the ARM64 backend. There are definitely
still some rough edges, so please bring up any issues you see with
this patch.
As with the LLVM commit though, we think it'll be more useful for
merging with AArch64 from within the tree.
llvm-svn: 205100
The peculiarities of C99 create scenario where an LLVM IR function
declaration may need to be replaced with a definition baring a different
type because the prototype and definition are not required to agree.
However, we were not properly deferring this when it occurred.
This fixes PR19280.
llvm-svn: 205099
This produces valid IR now that llvm rejects aliases to weak aliases and warns
the user that the resolution is not changed if the weak alias is overridden.
llvm-svn: 204935
COFF doesn't have mergeable sections so LLVM/clang's normal tactics for
string deduplication will not have any effect.
To remedy this we place each string inside it's own section and mark
the section as IMAGE_COMDAT_SELECT_ANY. However, we can only do this if the
string has an external name that we can generate from it's contents.
To be compatible with MSVC, we must use their scheme. Otherwise identical
strings in translation units from clang may not be deduplicated with
translation units in MSVC.
This fixes PR18248.
N.B. We will not attempt to do anything with a string literal which is not of
type 'char' or 'wchar_t' because their compiler does not support unicode
string literals as of this date. Further, we avoid doing this if
either -fwritable-strings or -fsanitize=address are present.
This reverts commit r204596.
llvm-svn: 204675
This commit cleans up a few accidents:
- Do not rely on the order in which StringLiteral lays out bytes.
- Use a more efficient mechanism for handling so-called
"special-mappings" when mangling string literals.
- There is no need to allocate a copy of the mangled name.
- Add the test written for r204562.
Thanks to Richard Smith for pointing these out!
llvm-svn: 204586
COFF doesn't have mergeable sections so LLVM/clang's normal tactics for
string deduplication will not have any effect.
To remedy this we place each string inside it's own section and mark
the section as IMAGE_COMDAT_SELECT_ANY. However, we can only do this if the
string has an external name that we can generate from it's contents.
To be compatible with MSVC, we must use their scheme. Otherwise identical
strings in translation units from clang may not be deduplicated with
translation units in MSVC.
This fixes PR18248.
N.B. We will not attempt to do anything with a string literal which is not of
type 'char' or 'wchar_t' because their compiler does not support unicode
string literals as of this date.
llvm-svn: 204562
This updates CodeGenPGO to use the ProfileDataReader introduced to
llvm in r203703 and the new API for writing out the profile introduced
to compiler-rt in r203710.
llvm-svn: 203711
r203364: what was use_iterator is now user_iterator, and there is
a use_iterator for directly iterating over the uses.
This also switches to use the range-based APIs where appropriate.
llvm-svn: 203365
LLVM currently has a hack (shouldEmitUsedDirectiveFor) that causes it to not
print no_dead_strip for symbols starting with 'l' or 'L'. These are exactly the
ones that the clang's objc codegen is producing. The net result, is that it is
equivalent to llvm.compiler.used.
The need for putting the private symbol in llvm.compiler.used should be clear
(the objc runtime uses them). The reason for also putting the weak symbols in
it is for LTO: ld64 will not ask us to preserve the it.
llvm-svn: 203172
We should only have this optimization fire when the explicit
instantiation definition would cause at least one member function to be
emitted, thus ensuring that even a compiler not performing this
optimization would still emit the full type information elsewhere.
But we should also pessimize output still by always emitting the
definition when the explicit instantiation definition appears so that at
some point in the future we can depend on that information even when no
code had to be emitted in that TU. (this shouldn't happen very often,
since people mostly use explicit spec decl/defs to reduce code size -
but perhaps one day they could use it to explicitly reduce debug info
size too)
This was worth about 2% for Clang and LLVM - so not a huge win, but a
win. It looks really great for simple STL programs (include <string> and
just declare a string - 14k -> 1.4k of .dwo)
llvm-svn: 202769
The __forceinline keyword's semantics are now recast as AlwaysInline and
the kw___forceinline token has its language mode set for KEYMS.
This preserves the semantics of the previous implementation but with
less duplication of code.
llvm-svn: 202131
