As dump() methods should be. To allow that, do not store the DWARFFormValue
objects used for the dump in the header data.
Per Alexey's suggestion!
llvm-svn: 222436
ELF targets (and maybe COFF) use relocations when referring
to strings in the .debug_str section. Handle that in the
accelerator table dumper. This commit restores the
test/DebugInfo/cross-cu-inlining.ll test to its expected
platform independant form, validating that the fix works
(this test failed on linux boxes).
llvm-svn: 222029
This reverts commit r221842 which was a revert of r221836 and of the
test parts of r221837.
This new version fixes an UB bug pointed out by David (along with
addressing some other review comments), makes some dumping more
resilient to broken input data and forces the accelerator tables
to be dumped in the tests where we use them (this decision is
platform specific otherwise).
llvm-svn: 222003
This reverts commit r221836.
The tests are asserting on some buildbots. This also reverts the
test part of r221837 as it relies on dwarfdump dumping the
accelerator tables.
llvm-svn: 221842
Currently FormValues are only used for attributes of DIEs and thus
uers always have a CU lying around when calling into the FormValue
API.
Accelerator tables encode their information using the same Forms
as the attributes, thus it is natural to use DWARFFormValue to
extract/dump them. There is no CU in that case though. Allow the
API to be called with a null CU arguemnt by making the RelocMap
lookup conditional on the CU pointer validity. And document this
new behvior in the header. (Test coverage for this use of the API
comes in the DwarfAccelTable support patch)
llvm-svn: 221835
This change depends on the ApplePropertyString helper that I sent spearately.
Not sure how you want this tested: as a tool test by adding a binary to dump, or as an llvm test starting from an IR file?
Reviewers: dblaikie, samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5689
llvm-svn: 219507
DW_AT_specification and DW_AT_abstract_origin resolving was only performed
on subroutine DIEs because it used the getSubroutineName method. Introduce
a more generic getName() and use it to dump the reference attributes.
Testcases have been updated to check the printed names instead of the offsets
except when the name could be ambiguous.
Reviewers: dblaikie, samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5625
llvm-svn: 219506
There are two methods in SectionRef that can fail:
* getName: The index into the string table can be invalid.
* getContents: The section might point to invalid contents.
Every other method will always succeed and returning and std::error_code just
complicates the code. For example, a section can have an invalid alignment,
but if we are able to get to the section structure at all and create a
SectionRef, we will always be able to read that invalid alignment.
llvm-svn: 219314
It would be more convenient to pass DWARFSection into DWARFUnitSection
constructor, instead of passing its components (Data and RelocAddrMap)
as a separate arguments.
llvm-svn: 219252
There will be multiple TypeUnits in an unlinked object that will be extracted
from different sections. Now that we have DWARFUnitSection that is supposed
to represent an input section, we need a DWARFUnitSection<TypeUnit> per
input .debug_types section.
Once this is done, the interface is homogenous and we can move the Section
parsing code into DWARFUnitSection.
This is a respin of r218513 that got reverted because it broke some builders.
This new version features an explicit move constructor for the DWARFUnitSection
class to workaround compilers unable to generate correct C++11 default
constructors.
Reviewers: samsonov, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5482
llvm-svn: 218606
Users of getSectionContents shouldn't try to pass in BSS or virtual
sections. In all instances, this is a bug in the code calling this
routine.
N.B. Some COFF implementations (like CL) will mark their BSS sections as
taking space on disk. This would confuse COFFObjectFile into thinking
the section is larger than the file.
llvm-svn: 218549
This reverts commit r218513.
Buildbots using libstdc++ issue an error when trying to copy
SmallVector<std::unique_ptr<>>. Revert the commit until we have a fix.
llvm-svn: 218514
Summary:
There will be multiple TypeUnits in an unlinked object that will be extracted
from different sections. Now that we have DWARFUnitSection that is supposed
to represent an input section, we need a DWARFUnitSection<TypeUnit> per
input .debug_types section.
Once this is done, the interface is homogenous and we can move the Section
parsing code into DWARFUnitSection.
Reviewers: samsonov, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5482
llvm-svn: 218513
This change replaces the brittle if/else chain of string comparisons
with a switch statement on the detected target triple, removing the
need for testing arbitrary architecture names returned from
getFileFormatName, whose primary purpose seems to be for display
(user-interface) purposes. The visitor now takes a reference to the
object file, rather than its arbitrary file format name to figure out
whether the file is a 32 or 64-bit object file and what the detected
target triple is.
A set of tests have been added to help show that the refactoring processes
relocations for the same targets as the original code.
Patch by Charlie Turner.
llvm-svn: 218406
This reverts commit faac033f7364bb4226e22c8079c221c96af10d02.
The test depends on all targets to be enabled in llc in order to pass,
and needs to be rewritten/refactored to not have that dependency.
llvm-svn: 218393
This change replaces the brittle if/else chain of string comparisons
with a switch statement on the detected target triple, removing the
need for testing arbitrary architecture names returned from
getFileFormatName, whose primary purpose seems to be for display
(user-interface) purposes. The visitor now takes a reference to the
object file, rather than its arbitrary file format name to figure out
whether the file is a 32 or 64-bit object file and what the detected
target triple is.
A set of tests have been added to help show that the refactoring processes
relocations for the same targets as the original code.
Patch by Charlie Turner.
llvm-svn: 218388
Summary: getSubroutineName is currently only used by llvm-symbolizer, thus add a binary test containing a cross-cu inlining example.
Reviewers: samsonov, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5394
llvm-svn: 218245
Summary:
getFileNameForUnit() is basically a wrapper around LineTable::getFileNameByIndex().
Fold its additional functionality (adding the DWARFUnit compilation dir) into
LineTable::getFileNameByIndex().
getFileLineInfoForCompileUnit() is a wrapper around getFileNameForUnit(). As
a function to search the line information by address, it seems natural to put
it in the LineTable also.
Before this commit only the Context with its private helpers could do Linetable
lookups. This newly exposed feature will be used by the DIE dumping code to
get access to file information referenced in DIE attributes.
This commit has already been partly reviewed in D5192 and contained an
additional and a bit controversial 'realpath' call that is left out of this
patch. We can reinstate that realpath code later if it is desirable.
Test Plan:
The patch contains no tests as it should be functionally equivalent to the
previous code. As requested in the last review, I checked if the relative
path handling copied from the Context to LineTable::getFileNameByIndex()
was covered, and indeed the symbolizer tests fail if it is removed.
Reviewers: dblaikie, echristo, aprantl, samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5354
llvm-svn: 218125
The current code is only able to return the right unit if the passed offset
is the exact offset of a section. Generalize the search function by comparing
againt the offset of the next unit instead and by switching the search
algorithm to upper_bound.
This way, the unit returned is the first unit with a getNextUnitOffset()
strictly greater than the searched offset, which is exactly what we want.
Note that there is no need for testing the range of the resulting unit as
the offsets of a DWARFUnitSection are in a single contiguous range from
0 inclusive to lastUnit->getNextUnitOffset() exclusive.
Reviewers: dblaikie samsonov
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5262
llvm-svn: 218040
Use fully qualified name inside a typedef from llvm::iterator_range<...> to
iterator_range. This is reported (rightly I think) by GCC as an
ambiguous name redefinition. Hope this fixes the buildbots.
llvm-svn: 217751
A DWARFUnitSection is the collection of Units that have been extracted from
the same debug section.
By embeding a reference to their DWARFUnitSection in each unit, the DIEs
will be able to resolve inter-unit references by interrogating their Unit's
DWARFUnitSection.
This is a minimal patch where the DWARFUnitSection is-a SmallVector of Units,
thus exposing exactly the same interface as before. Followup-up patches might
change from inheritance to composition in order to expose only the wanted
DWARFUnitSection abstraction.
Differential Revision: http://reviews.llvm.org/D5310
llvm-svn: 217747
The DWARFContext will be used to pass global 'context' down, like
pointers to related debug info sections or command line options.
The first use will be for the debug_info dumper to be able to access
other debug info section to dump eg. Location Expression inline
in the debug_info dump.
llvm-svn: 217128
Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.
Keeping this ownership would make supporting IR inside native objects
particularly painful.
This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.
This patch introduces a few new types.
* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
for convenience functions that take a filename and return both the
buffer and the Binary using that buffer.
The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.
llvm-svn: 216002
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)
Changes made by clang-tidy with minor tweaks.
llvm-svn: 215558
string_ostream is a safe and efficient string builder that combines opaque
stack storage with a built-in ostream interface.
small_string_ostream<bytes> additionally permits an explicit stack storage size
other than the default 128 bytes to be provided. Beyond that, storage is
transferred to the heap.
This convenient class can be used in most places an
std::string+raw_string_ostream pair or SmallString<>+raw_svector_ostream pair
would previously have been used, in order to guarantee consistent access
without byte truncation.
The patch also converts much of LLVM to use the new facility. These changes
include several probable bug fixes for truncated output, a programming error
that's no longer possible with the new interface.
llvm-svn: 211749
Previous algorithm for constructing [Address ranges]->[Compile Units]
mapping was wrong. It somewhat relied on the assumption that address ranges
for different compile units may not overlap. It is not so.
For example, two compile units may contain the definition of the same
linkonce_odr function. These definitions will be merged at link-time,
resulting in equivalent .debug_ranges entries for both these units
Instead of sorting and merging original address ranges (from .debug_ranges
and .debug_aranges), implement a different approach: save endpoints
of all ranges, and then use a sweep-line approach to construct
the desired mapping. If we find that certain address maps to
several compilation units, we just pick any of them.
llvm-svn: 210860
Turns out that DW_AT_ranges_base attribute sets the offset for
DW_AT_ranges values specified in the .dwo file, but not for DW_AT_ranges specified
in the skeleton compile unit DIE in the main executable. This is extremely confusing,
and would hopefully be fixed in DWARF-5 when it's finalized. For now this
behavior makes sense, as otherwise Fission would break DWARF consumers who
doesn't know anything about DW_AT_ranges_base.
llvm-svn: 210809
Change --functions option in llvm-symbolizer tool to accept
values "none", "short" or "linkage". Update the tests and docs
accordingly.
llvm-svn: 209050
It is more appropriate than the current situation, when one flag
(AbsoluteFilePath) is relevant only if another flag is set.
This refactoring would also simplify fetching the short function name
(stored in DW_AT_name) instead of a linkage name returned currently.
No functionality change.
llvm-svn: 208921
Streamline parsing and dumping line tables:
Prefer composition to multiple inheritance in DWARFDebugLine::ParsingState.
Get rid of the weird concept of "DumpingState" structure.
was:
DWARFDebugLine::DumpingState state(OS);
DWARFDebugLine::parseStatementTable(..., state);
now:
DWARFDebugLine::LineTable LineTable;
LineTable.parse(...);
LineTable.dump(OS);
No functionality change.
llvm-svn: 207599
Move several function definitions into .cpp, unify constructors
and clear() methods (fixing a couple of latent bugs from copy-paste),
turn static function parsePrologue() into Prologue::parse().
More work needed here to untangle weird multiple inheritance
in table parsing and dumping.
No functionality change.
llvm-svn: 207579
DIE doesn't need to store a pointer to its parent: we can traverse the DIE tree
only with functions getFirstChild() and getSibling(). Parents must be known
only when we construct the tree. Rewrite setDIERelations() procedure in a more
straightforward way, and get rid of lots of now unused DIEMinimal methods.
No functionality change.
llvm-svn: 207563
FrameEntry doesn't need to hold a reference to the section it is
located in. Instead, pass DataExtractor as an argument of parsing
function.
No functionality change.
llvm-svn: 207461
There is no need to keep the whole contents of .debug_aranges section
in memory when we build address ranges table. Memory optimization that
used to be in this code (precalculate the size of vector of ranges before
filling it) is not really needed - later we will compact and resize this
vector anyway.
llvm-svn: 207457
behavior based on other files defining DEBUG_TYPE, which means it cannot
define DEBUG_TYPE at all. This is actually better IMO as it forces folks
to define relevant DEBUG_TYPEs for their files. However, it requires all
files that currently use DEBUG(...) to define a DEBUG_TYPE if they don't
already. I've updated all such files in LLVM and will do the same for
other upstream projects.
This still leaves one important change in how LLVM uses the DEBUG_TYPE
macro going forward: we need to only define the macro *after* header
files have been #include-ed. Previously, this wasn't possible because
Debug.h required the macro to be pre-defined. This commit removes that.
By defining DEBUG_TYPE after the includes two things are fixed:
- Header files that need to provide a DEBUG_TYPE for some inline code
can do so by defining the macro before their inline code and undef-ing
it afterward so the macro does not escape.
- We no longer have rampant ODR violations due to including headers with
different DEBUG_TYPE definitions. This may be mostly an academic
violation today, but with modules these types of violations are easy
to check for and potentially very relevant.
Where necessary to suppor headers with DEBUG_TYPE, I have moved the
definitions below the includes in this commit. I plan to move the rest
of the DEBUG_TYPE macros in LLVM in subsequent commits; this one is big
enough.
The comments in Debug.h, which were hilariously out of date already,
have been updated to reflect the recommended practice going forward.
llvm-svn: 206822
This is important for symbolizing executables with debug info in
unavailable .dwo files. Even if all DIE entries are missing, we can
still symbolize an address: function name can be fetched from symbol table,
and file/line info can be fetched from line table.
llvm-svn: 206665
Immutable DILineInfo doesn't bring any benefits and complicates
code. Also, use std::string instead of SmallString<16> for file
and function names - their length can vary significantly.
No functionality change.
llvm-svn: 206654
When address ranges for compile unit are specified in compile unit DIE
itself, there is no need to collect ranges from children subprogram DIEs.
This change speeds up llvm-symbolizer on Clang-produced binaries with
full debug info. For instance, symbolizing a first address in a 1Gb binary
is now 2x faster (1s vs. 2s).
llvm-svn: 206641
Add a helper method to get address ranges specified in a DIE
(either by DW_AT_low_pc/DW_AT_high_pc, or by DW_AT_ranges). Use it
to untangle and simplify the code.
No functionality change.
llvm-svn: 206624
This avoids an extra copy during decompression and avoids the use of
MemoryBuffer which is a weirdly esoteric device that includes unrelated
concepts like "file name" (its rather generic name is a bit misleading).
Similar refactoring of zlib::compress coming up.
llvm-svn: 205676
Implement debug_loc.dwo, as well as llvm-dwarfdump support for dumping
this section.
Outlined in the DWARF5 spec and http://gcc.gnu.org/wiki/DebugFission the
debug_loc.dwo section has more variation than the standard debug_loc,
allowing 3 different forms of entry (plus the end of list entry). GCC
seems to, and Clang certainly, only use one form, so I've just
implemented dumping support for that for now.
It wasn't immediately obvious that there was a good refactoring to share
the implementation of dumping support between debug_loc and
debug_loc.dwo, so they're separate for now - ideas welcome or I may come
back to it at some point.
As per a comment in the code, we could choose different forms that may
reduce the number of debug_addr entries we emit, but that will require
further study.
llvm-svn: 204697
Summary:
This adds ObjectFile::section_iterator_range, that allows to write
range-based for-loops running over all sections of a given file.
Several files from lib/ are converted to the new interface. Similar fixes
should be applied to a variety of llvm-* tools.
Reviewers: rafael
Reviewed By: rafael
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3069
llvm-svn: 203799
This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
llvm-svn: 203083
Summary:
This adds support for emitting DWARF path discriminator values in
the object streamer. It also changes the DWARF dumper to show
discriminator values in the line table output.
Reviewers: echristo
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2794
llvm-svn: 201427
sections. The call to data.getUnsigned(&Offset, AddressSize) only
increments Offset if the read succeeds, which will result in an infinite
loop.
llvm-svn: 201179
None of the object file formats reported error on iterator increment. In
retrospect, that is not too surprising: no object format stores symbols or
sections in a linked list or other structure that requires chasing pointers.
As a consequence, all error checking can be done on begin() and end().
This reduces the text segment of bin/llvm-readobj in my machine from 521233 to
518526 bytes.
llvm-svn: 200442
This makes it easier to write a test that's mostly shared between
fission and non-fission (using FileCheck's multiple prefix support).
llvm-svn: 198806
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.
Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.
llvm-svn: 198685
This commit does not complete the type units feature - there are issues
around fission support (skeletal type units, pubtypes/pubnames) and
hashing of some types including those containing references to types in
other type units.
Originally committed as r197073 and reverted in r197079.
Recommitted as r197197 to reproduce the failure and reverted as r197199
Turns out there was unstable ordering in the type unit dumping code.
Fixed by using MapVector in DWARFContext to store the debug_types
comdat sections.
Recommitted as r197210 with a fix to dumping and reverted as r197211
because I was a bit gun shy and thought I saw a failure that turned out
to be unrelated.
So here we go - once more with feeling! \o/
llvm-svn: 197275
This commit does not complete the type units feature - there are issues
around fission support (skeletal type units, pubtypes/pubnames) and
hashing of some types including those containing references to types in
other type units.
Originally committed as r197073 and reverted in r197079.
Recommitted as r197197 to reproduce the failure and reverted as r197199
Turns out there was unstable ordering in the type unit dumping code.
Fixed by using MapVector in DWARFContext to store the debug_types
comdat sections.
llvm-svn: 197210
In a failed attempt to allow the gnu-public-names.ll test case to not
hardcode the size of the unit that the pubnames section referred to I've
at least managed to have unit headers and pubnames headers print out in
a similar style.
This failed to achieve the desired goal because the header in a unit
specifies the length of the unit without the length element of the
header whereas the length in the pubnames includes this element, so the
numbers are off by 4 bytes. I don't know of any arithmetic powers in
FileCheck so the test case can't simply say "CU_LENGTH + 4".
llvm-svn: 193872
MSVC can't comprehend
template<typename T, size_t N>
ArrayRef<T> makeArrayRef(const T (&Arr)[N]) {
return ArrayRef<T>(Arr);
}
if Arr is
static const uint8_t sizes[];
declared in a templated and defined a few lines later.
I'll send a proper fix (i.e. get rid of unnecessary templates) for review soon.
llvm-svn: 193604
Complicated CU-DIE-specific logic in the latter was never used,
and it makes sense to have safety checks for broken dwarf in the former.
llvm-svn: 193563
Summary:
Use DWARF4 table of form classes to fetch attributes from DIE
in a more consistent way. This shouldn't change the functionality and
serves as a refactoring for upcoming change: DW_AT_high_pc has different
semantics depending on its form class.
Reviewers: dblaikie, echristo
Reviewed By: echristo
CC: echristo, llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1961
llvm-svn: 193553
Parsing .debug_aranges section now takes O(nlogn) operations instead
of O(n^2), where "n" is the number of address ranges. With this change,
the time required to symbolize an address from a random large
Clang-generated binary drops from 165 seconds to 1.5 seconds.
No functionality change.
llvm-svn: 191781
This is a small step that may enable some simplifications in producer
(DWARFContext) and consumer (DWARFCompileUnit and other places) by
making a more complete abstraction around the data and relocations for a
section. Small initial steps could include simple changes such as
passing the pair to DWARFCompileUnit's ctor rather than passing the data
and relocs separately. I don't intend to pursue any such changes
immediately, however.
The motivation for doing this now is that type unit dumping will need to
deal with these data+reloc pairs moreso than the existing dumping
support has needed to associate the data as type unit sections are named
the same (debug_types) and comdat group folded. So to implement dumping
and reloc handling we'll need a mapping of section->data+relocs.
llvm-svn: 191209
Ensures that the pubnames entries actually refer to the intended
entities. This test could be more flexible if there was a way to do
multiline FileCheck matches with captures (in that way the test wouldn't
need to have hardcoded offset values and would thus be resilient to
changes in the layout of the DIEs in this CU).
llvm-svn: 191055
Summary:
1) Make llvm-symbolizer properly symbolize
files with split debug info (by using stanalone .dwo files).
2) Make DWARFCompileUnit parse and store corresponding .dwo file,
if necessary.
3) Make bits of DWARF parsing more CompileUnit-oriented.
Reviewers: echristo
Reviewed By: echristo
CC: bkramer, llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1164
llvm-svn: 189329
Summary:
This is a part of D1164. DWARFCompileUnit is not that lightweight
to copy it around, and we want it to own corresponding .dwo compile unit
eventually.
Reviewers: echristo
Reviewed By: echristo
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1298
llvm-svn: 189089
This reduces the noise in diffs making it more likely that, at least for
LLVM revision-over-revision, diffs will actually yield usable results.
This is consistent with objdump's DWARF dumping behavior.
llvm-svn: 188650
This is a basic implementation - we still don't have any support (that I
know of) for dumping DWARF expressions in a meaningful way, so the
location information itself is just printed as a sequence of bytes as we
do elsewhere.
llvm-svn: 184361
In ELF (as in MachO), not all relocations point to symbols. Represent this
properly by using a symbol_iterator instead of a SymbolRef. Update llvm-readobj
ELF's dumper to handle relocatios without symbols.
llvm-svn: 183284
For COFF and MachO, sections semantically have relocations that apply to them.
That is not the case on ELF.
In relocatable objects (.o), a section with relocations in ELF has offsets to
another section where the relocations should be applied.
In dynamic objects and executables, relocations don't have an offset, they have
a virtual address. The section sh_info may or may not point to another section,
but that is not actually used for resolving the relocations.
This patch exposes that in the ObjectFile API. It has the following advantages:
* Most (all?) clients can handle this more efficiently. They will normally walk
all relocations, so doing an effort to iterate in a particular order doesn't
save time.
* llvm-readobj now prints relocations in the same way the native readelf does.
* probably most important, relocations that don't point to any section are now
visible. This is the case of relocations in the rela.dyn section. See the
updated relocation-executable.test for example.
llvm-svn: 182908
getRelocationAddress is for dynamic libraries and executables,
getRelocationOffset for relocatable objects.
Mark the getRelocationAddress of COFF and MachO as not implemented yet. Add a
test of ELF's. llvm-readobj -r now prints the same values as readelf -r.
llvm-svn: 180259
a relocation across sections. Do this for DW_AT_stmt list in the
skeleton CU and check the relocations in the debug_info section.
Add a FIXME for multiple CUs.
llvm-svn: 178969
to lib/DebugInfo, with dumping in llvm-dwarfdump. This patch adds
initial ability to parse and dump CFA instructions contained in
entries.
To keep it manageable, the patch omits some more advanced capabilities
(accounted in TODOs):
* Parsing of instructions with BLOCK arguments (expression lists)
* Dumping of actual instruction arguments (currently only names are
dumped). This is quite tricky since the dumper has to effectively
"interpret" the instructions.
llvm-svn: 175820
of lines which weren't being explicitly looked at and were printing incorrect results. These
values clearly must lie within 32 bits, so the casts are definitely safe.
llvm-svn: 174717
Frederic Riss