summaryrefslogtreecommitdiffstats
path: root/clang/lib/Sema/SemaExpr.cpp
Commit message (Collapse)AuthorAgeFilesLines
...
* Forbid address spaces on compound literals in local scope.John McCall2018-09-051-6/+14
| | | | | | Patch by Bevin Hansson! llvm-svn: 341491
* [Sema][NFC] Trivial cleanup in ActOnCallExprJan Korous2018-08-301-7/+1
| | | | | | | | Use logical or operator instead of a bool variable and if/else. Differential Revision: https://reviews.llvm.org/D51485 llvm-svn: 341074
* Model type attributes as regular Attrs.Richard Smith2018-08-201-4/+4
| | | | | | | | | | | | | | Specifically, AttributedType now tracks a regular attr::Kind rather than having its own parallel Kind enumeration, and AttributedTypeLoc now holds an Attr* instead of holding an ad-hoc collection of Attr fields. Differential Revision: https://reviews.llvm.org/D50526 This reinstates r339623, reverted in r339638, with a fix to not fail template instantiation if we instantiate a QualType with no associated type source information and we encounter an AttributedType. llvm-svn: 340215
* [ObjC] Error out when using forward-declared protocol in a @protocolAlex Lorenz2018-08-171-10/+0
| | | | | | | | | | | | | | | | | | | | | | expression Clang emits invalid protocol metadata when a @protocol expression is used with a forward-declared protocol. The protocol metadata is missing protocol conformance list of the protocol since we don't have access to the definition of it in the compiled translation unit. The linker then might end up picking the invalid metadata when linking which will lead to incorrect runtime protocol conformance checks. This commit makes sure that Clang fails to compile code that uses a @protocol expression with a forward-declared protocol. This ensures that Clang does not emit invalid protocol metadata. I added an extra assert in CodeGen to ensure that this kind of issue won't happen in other places. rdar://32787811 Differential Revision: https://reviews.llvm.org/D49462 llvm-svn: 340102
* Revert r339623 "Model type attributes as regular Attrs."Reid Kleckner2018-08-141-4/+4
| | | | | | | | This breaks compiling atlwin.h in Chromium. I'm sure the code is invalid in some way, but we put a lot of work into accepting it, and I'm sure rejecting it was not an intended consequence of this refactoring. :) llvm-svn: 339638
* Model type attributes as regular Attrs.Richard Smith2018-08-131-4/+4
| | | | | | | | | | Specifically, AttributedType now tracks a regular attr::Kind rather than having its own parallel Kind enumeration, and AttributedTypeLoc now holds an Attr* instead of holding an ad-hoc collection of Attr fields. Differential Revision: https://reviews.llvm.org/D50526 llvm-svn: 339623
* Port getLocEnd -> getEndLocStephen Kelly2018-08-091-27/+26
| | | | | | | | | | Reviewers: teemperor! Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D50351 llvm-svn: 339386
* Port getLocStart -> getBeginLocStephen Kelly2018-08-091-156/+152
| | | | | | | | | | Reviewers: teemperor! Subscribers: jholewinski, whisperity, jfb, cfe-commits Differential Revision: https://reviews.llvm.org/D50350 llvm-svn: 339385
* [Sema] Fix for crash on conditional operation with address_space pointerLeonard Chan2018-08-071-24/+20
| | | | | | | | | | | | | | | | | | | | | | Compiling the following causes clang to crash ``` char *cmp(__attribute__((address_space(1))) char *x, __attribute__((address_space(2))) char *y) { return x < y ? x : y; } ``` with the message: "wrong cast for pointers in different address spaces(must be an address space cast)!" This is because during IR emission, the source and dest type for a bitcast should not have differing address spaces. This fix prints an error since the code shouldn't compile in the first place. Differential Revision: https://reviews.llvm.org/D50278 llvm-svn: 339167
* [Fixed Point Arithmetic] Fixed Point ConstantLeonard Chan2018-08-061-5/+4
| | | | | | | | | | This patch proposes an abstract type that represents fixed point numbers, similar to APInt or APSInt that was discussed in https://reviews.llvm.org/D48456#inline-425585. This type holds a value, scale, and saturation and is meant to perform intermediate calculations on constant fixed point values. Currently this class is used as a way for handling the conversions between fixed point numbers with different sizes and radixes. For example, if I'm casting from a signed _Accum to a saturated unsigned short _Accum, I will need to check the value of the signed _Accum to see if it fits into the short _Accum which involves getting and comparing against the max/min values of the short _Accum. The FixedPointNumber class currently handles the radix shifting and extension when converting to a signed _Accum. Differential Revision: https://reviews.llvm.org/D48661 llvm-svn: 339028
* Try to make builtin address space declarations not uselessMatt Arsenault2018-08-021-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way address space declarations for builtins currently work is nearly useless. The code assumes the address spaces used for builtins is a confusingly named "target address space" from user code using __attribute__((address_space(N))) that matches the builtin declaration. There's no way to use this to declare a builtin that returns a language specific address space. The terminology used is highly cofusing since it has nothing to do with the the address space selected by the target to use for a language address space. This feature is essentially unused as-is. AMDGPU and NVPTX are the only in-tree targets attempting to use this. The AMDGPU builtins certainly do not behave as intended (i.e. all of the builtins returning pointers can never compile because the numbered address space never matches the expected named address space). The NVPTX builtins are missing tests for some, and the others seem to rely on an implicit addrspacecast. Change the used address space for builtins based on a target hook to allow using a language address space for a builtin. This allows the same builtin declaration to be used for multiple languages with similarly purposed address spaces (e.g. the same AMDGPU builtin can be used in OpenCL and CUDA even though the constant address spaces are arbitarily different). This breaks the possibility of using arbitrary numbered address spaces alongside the named address spaces for builtins. If this is an issue we probably need to introduce another builtin declaration character to distinguish language address spaces from so-called "target address spaces". llvm-svn: 338707
* Remove trailing spaceFangrui Song2018-07-301-223/+223
| | | | | | sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h} llvm-svn: 338291
* Add missing temporary materialization conversion on left-hand side of .Richard Smith2018-07-271-0/+6
| | | | | | | | | in some member function calls. Specifically, when calling a conversion function, we would fail to create the AST node representing materialization of the class object. llvm-svn: 338135
* [MS] Add L__FUNCSIG__ for compatibilityReid Kleckner2018-07-261-2/+3
| | | | | | | | | | Clang already has L__FUNCTION__ as a workaround for dealing with pre-processor code that expects to be able to do L##__FUNCTION__ in a macro. This patch implements the same logic for __FUNCSIG__. Fixes PR38295. llvm-svn: 338083
* Separate out the initialization kind for a statement expression resultRichard Smith2018-07-231-5/+2
| | | | | | | | | | from that for a return value. No functionality change intended: I don't believe any of the diagnostics affected by this patch are reachable when initializing the result of statement expression. llvm-svn: 337728
* PR38257: don't perform ADL when instantiating a unary & operator that turns outRichard Smith2018-07-221-1/+1
| | | | | | to be forming a pointer-to-member. llvm-svn: 337653
* Implement cpu_dispatch/cpu_specific MultiversioningErich Keane2018-07-201-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As documented here: https://software.intel.com/en-us/node/682969 and https://software.intel.com/en-us/node/523346. cpu_dispatch multiversioning is an ICC feature that provides for function multiversioning. This feature is implemented with two attributes: First, cpu_specific, which specifies the individual function versions. Second, cpu_dispatch, which specifies the location of the resolver function and the list of resolvable functions. This is valuable since it provides a mechanism where the resolver's TU can be specified in one location, and the individual implementions each in their own translation units. The goal of this patch is to be source-compatible with ICC, so this implementation diverges from the ICC implementation in a few ways: 1- Linux x86/64 only: This implementation uses ifuncs in order to properly dispatch functions. This is is a valuable performance benefit over the ICC implementation. A future patch will be provided to enable this feature on Windows, but it will obviously more closely fit ICC's implementation. 2- CPU Identification functions: ICC uses a set of custom functions to identify the feature list of the host processor. This patch uses the cpu_supports functionality in order to better align with 'target' multiversioning. 1- cpu_dispatch function def/decl: ICC's cpu_dispatch requires that the function marked cpu_dispatch be an empty definition. This patch supports that as well, however declarations are also permitted, since the linker will solve the issue of multiple emissions. Differential Revision: https://reviews.llvm.org/D47474 llvm-svn: 337552
* [C++17] Disallow lambdas in template parameters (PR33696).Nicolas Lesser2018-07-121-21/+22
| | | | | | | | | | | | | | Summary: This revision disallows lambdas in template parameters, as reported in PR33696. Reviewers: rsmith Reviewed By: rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D37442 llvm-svn: 336930
* [Sema] Discarded statment should be an evaluatable context.Erik Pilkington2018-07-031-1/+1
| | | | | | | | | | The constexpr evaluator was erroring out because these templates weren't defined. Despite being used in a discarded statement, we still need to constexpr evaluate them, which means that we need to instantiate them. Fixes PR37585. Differential revision: https://reviews.llvm.org/D48322 llvm-svn: 336233
* [Fixed Point Arithmetic] Rename `-fsame-fbits` flagLeonard Chan2018-06-291-1/+1
| | | | | | | | | | | - Rename the `-fsame-fbits` flag to `-fpadding-on-unsigned-fixed-point` - Move the flag from a driver option to a cc1 option - Rename the `SameFBits` member in TargetInfo to `PaddingOnUnsignedFixedPoint` - Updated descriptions Differential Revision: https://reviews.llvm.org/D48727 llvm-svn: 335993
* DR1687: When overload resolution selects a built-in operator, implicitRichard Smith2018-06-271-3/+42
| | | | | | | | | | | conversions are only applied to operands of class type, and the second standard conversion sequence is not applied. When diagnosing an invalid builtin binary operator, talk about the original types rather than the converted types. If these differ by a user-defined conversion, tell the user what happened. llvm-svn: 335781
* DR1213: Ignore implicit conversions when determining if an operand of anRichard Smith2018-06-271-4/+14
| | | | | | | | array subscript expression is an array prvalue. Also apply DR1213 to vector prvalues for consistency. llvm-svn: 335779
* [Fixed Point Arithmetic] Fixed Point Precision Bits and Fixed Point LiteralsLeonard Chan2018-06-201-2/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This diff includes the logic for setting the precision bits for each primary fixed point type in the target info and logic for initializing a fixed point literal. Fixed point literals are declared using the suffixes ``` hr: short _Fract uhr: unsigned short _Fract r: _Fract ur: unsigned _Fract lr: long _Fract ulr: unsigned long _Fract hk: short _Accum uhk: unsigned short _Accum k: _Accum uk: unsigned _Accum ``` Errors are also thrown for illegal literal values ``` unsigned short _Accum u_short_accum = 256.0uhk; // expected-error{{the integral part of this literal is too large for this unsigned _Accum type}} ``` Differential Revision: https://reviews.llvm.org/D46915 llvm-svn: 335148
* Revert r335019 "Update NRVO logic to support early return (Attempt 2)"Taiju Tsuiki2018-06-191-3/+7
| | | | llvm-svn: 335022
* Update NRVO logic to support early return (Attempt 2)Taiju Tsuiki2018-06-191-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This is the second attempt of r333500 (Update NRVO logic to support early return). The previous one was reverted for a miscompilation for an incorrect NRVO set up on templates such as: ``` struct Foo {}; template <typename T> T bar() { T t; if (false) return T(); return t; } ``` Where, `t` is marked as non-NRVO variable before its instantiation. However, while its instantiation, it's left an NRVO candidate, turned into an NRVO variable later. Reviewers: rsmith Reviewed By: rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D47586 llvm-svn: 335019
* Revert "Update NRVO logic to support early return"Sam McCall2018-05-301-3/+7
| | | | | | This reverts commit r333500, which causes stage2 compiler crashes. llvm-svn: 333547
* Update NRVO logic to support early returnTaiju Tsuiki2018-05-301-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The previous implementation misses an opportunity to apply NRVO (Named Return Value Optimization) below. That discourages user to write early return code. ``` struct Foo {}; Foo f(bool b) { if (b) return Foo(); Foo oo; return oo; } ``` That is, we can/should apply RVO for a local variable if: * It's directly returned by at least one return statement. * And, all reachable return statements in its scope returns the variable directly. While, the previous implementation disables the RVO in a scope if there are multiple return statements that refers different variables. On the new algorithm, local variables are in NRVO_Candidate state at first, and a return statement changes it to NRVO_Disabled for all visible variables but the return statement refers. Then, at the end of the function AST traversal, NRVO is enabled for variables in NRVO_Candidate state and refers from at least one return statement. Reviewers: rsmith Reviewed By: rsmith Subscribers: xbolva00, Quuxplusone, arthur.j.odwyer, cfe-commits Differential Revision: https://reviews.llvm.org/D47067 llvm-svn: 333500
* Remove the fixit for the diagnostics regarding capturing autoreleasing ↵George Karpenkov2018-05-141-24/+0
| | | | | | | | | | | | | | | variables in a block The fixit is actively harmful, as it encourages developers to ignore the warning and to write unsafe code. It is almost impossible to write safe code while capturing autoreleasing variables in the block, as in order to check that the block is never called in the autoreleasing pool the developer has to check the transitive closure of all potential callers of the block. Differential Revision: https://reviews.llvm.org/D46778 llvm-svn: 332288
* Improve diagnostics and error recovery for template name lookup.Richard Smith2018-05-111-2/+3
| | | | | | | | | | | | | For 'x::template y', consistently give a "no member named 'y' in 'x'" diagnostic if there is no such member, and give a 'template keyword not followed by a template' name error if there is such a member but it's not a template. In the latter case, add a note pointing at the non-template. Don't suggest inserting a 'template' keyword in 'X::Y<' if X is dependent if the lookup of X::Y was actually not a dependent lookup and found only non-templates. llvm-svn: 332076
* [OpenCL] Add constant address space to __func__ in AST.Anastasia Stulova2018-05-091-13/+10
| | | | | | | | | | | | Added string literal helper function to obtain the type attributed by a constant address space. Also fixed predefind __func__ expr to use the helper to constract the string literal correctly. Differential Revision: https://reviews.llvm.org/D46049 llvm-svn: 331877
* Remove \brief commands from doxygen comments.Adrian Prantl2018-05-091-69/+69
| | | | | | | | | | | | | | | | | | | This is similar to the LLVM change https://reviews.llvm.org/D46290. We've been running doxygen with the autobrief option for a couple of years now. This makes the \brief markers into our comments redundant. Since they are a visual distraction and we don't want to encourage more \brief markers in new code either, this patch removes them all. Patch produced by for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done Differential Revision: https://reviews.llvm.org/D46320 llvm-svn: 331834
* [C++2a] Implement operator<=>: Address bugs and post-commit review comments ↵Eric Fiselier2018-05-081-4/+4
| | | | | | | | | | | | after r331677. This patch addresses some mostly trivial post-commit review comments received on r331677. Additionally, this patch fixes an assertion in `getNarrowingKind` caused by the use of an uninitialized value from `checkThreeWayNarrowingConversion`. llvm-svn: 331707
* [C++2a] Implement operator<=> CodeGen and ExprConstantEric Fiselier2018-05-071-54/+279
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This patch tackles long hanging fruit for the builtin operator<=> expressions. It is currently needs some cleanup before landing, but I want to get some initial feedback. The main changes are: * Lookup, build, and store the required standard library types and expressions in `ASTContext`. By storing them in ASTContext we don't need to store (and duplicate) the required expressions in the BinaryOperator AST nodes. * Implement [expr.spaceship] checking, including diagnosing narrowing conversions. * Implement `ExprConstant` for builtin spaceship operators. * Implement builitin operator<=> support in `CodeGenAgg`. Initially I emitted the required comparisons using `ScalarExprEmitter::VisitBinaryOperator`, but this caused the operand expressions to be emitted once for every required cmp. * Implement [builtin.over] with modifications to support the intent of P0946R0. See the note on `BuiltinOperatorOverloadBuilder::addThreeWayArithmeticOverloads` for more information about the workaround. Reviewers: rsmith, aaron.ballman, majnemer, rnk, compnerd, rjmccall Reviewed By: rjmccall Subscribers: rjmccall, rsmith, aaron.ballman, junbuml, mgorny, cfe-commits Differential Revision: https://reviews.llvm.org/D45476 llvm-svn: 331677
* Implement P0482R2, support for char8_t type.Richard Smith2018-05-011-0/+4
| | | | | | | | | | | | This is not yet part of any C++ working draft, and so is controlled by the flag -fchar8_t rather than a -std= flag. (The GCC implementation is controlled by a flag with the same name.) This implementation is experimental, and will be removed or revised substantially to match the proposal as it makes its way through the C++ committee. llvm-svn: 331244
* Parse A::template B as an identifier rather than as a template-id with noRichard Smith2018-04-271-2/+5
| | | | | | | | | | template arguments. This fixes some cases where we'd incorrectly accept "A::template B" when B is a kind of template that requires template arguments (in particular, a variable template or a concept). llvm-svn: 331013
* Factor out common code for diagnosing missing template arguments.Richard Smith2018-04-261-3/+1
| | | | | | In passing, add 'concept' to the list of template kinds in diagnostics. llvm-svn: 330890
* [Sema] Add -Wno-self-assign-overloadedRoman Lebedev2018-04-231-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: It seems there isn't much enthusiasm for `-wtest` D45685. This is more conservative version, which i had in the very first revision of D44883, but that 'erroneously' got removed because of the review. **Based on some [irc] discussions, it must really be documented that we want all the new diagnostics to have their own flags, to ease rollouts, transitions, etc.** Please do note that i'm only adding `-Wno-self-assign-overloaded`, but not `-Wno-self-assign-field-overloaded`, because i'm honestly not aware of any false-positives from the `-field` variant, but i can just as easily add it if wanted. https://reviews.llvm.org/D44883#1068561 Reviewers: dblaikie, aaron.ballman, thakis, rjmccall, rsmith Reviewed By: dblaikie Subscribers: Quuxplusone, chandlerc, cfe-commits Differential Revision: https://reviews.llvm.org/D45766 llvm-svn: 330651
* [OPENMP] Code cleanup and code improvements.Alexey Bataev2018-04-181-5/+5
| | | | llvm-svn: 330270
* Revert r329684 (and follow-ups 329693, 329714). See discussion on ↵Nico Weber2018-04-101-15/+0
| | | | | | https://reviews.llvm.org/D43578. llvm-svn: 329739
* -ftime-report switch support in Clang.Andrew V. Tischenko2018-04-101-0/+15
| | | | | | | | | | The current support of the feature produces only 2 lines in report: -Some general Code Generation Time; -Total time of Backend Consumer actions. This patch extends Clang time report with new lines related to Preprocessor, Include Filea Search, Parsing, etc. Differential Revision: https://reviews.llvm.org/D43578 llvm-svn: 329684
* Allow equality comparisons between block pointers andJohn McCall2018-04-071-0/+13
| | | | | | | | block-pointer-compatible ObjC object pointer types. Patch by Dustin Howett! llvm-svn: 329508
* [Sema] Extend -Wself-assign and -Wself-assign-field to warn on overloaded ↵Roman Lebedev2018-04-071-5/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | self-assignment (classes) Summary: This has just bit me, so i though it would be nice to avoid that next time :) Motivational case: https://godbolt.org/g/cq9UNk Basically, it's likely to happen if you don't like shadowing issues, and use `-Wshadow` and friends. And it won't be diagnosed by clang. The reason is, these self-assign diagnostics only work for builtin assignment operators. Which makes sense, one could have a very special operator=, that does something unusual in case of self-assignment, so it may make sense to not warn on that. But while it may be intentional in some cases, it may be a bug in other cases, so it would be really great to have some diagnostic about it... Reviewers: aaron.ballman, rsmith, rtrieu, nikola, rjmccall, dblaikie Reviewed By: rjmccall Subscribers: EricWF, lebedev.ri, thakis, Quuxplusone, cfe-commits Differential Revision: https://reviews.llvm.org/D44883 llvm-svn: 329493
* Fix typos in clangAlexander Kornienko2018-04-061-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Found via codespell -q 3 -I ../clang-whitelist.txt Where whitelist consists of: archtype cas classs checkk compres definit frome iff inteval ith lod methode nd optin ot pres statics te thru Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few files that have dubious fixes reverted.) Differential revision: https://reviews.llvm.org/D44188 llvm-svn: 329399
* Revert "Set calling convention for CUDA kernel"Artem Belevich2018-04-031-11/+0
| | | | | | | This reverts r328795 which introduced an issue with referencing __global__ function templates. More details in the original review D44747. llvm-svn: 329099
* [Sema] Make deprecation fix-it replace all multi-parameter ObjC method slots.Volodymyr Sapsai2018-03-291-2/+3
| | | | | | | | | | | | | | | | | | Deprecation replacement can be any text but if it looks like a name of ObjC method and has the same number of arguments as original method, replace all slot names so after applying a fix-it you have valid code. rdar://problem/36660853 Reviewers: aaron.ballman, erik.pilkington, rsmith Reviewed By: erik.pilkington Subscribers: cfe-commits, jkorous-apple Differential Revision: https://reviews.llvm.org/D44589 llvm-svn: 328807
* Set calling convention for CUDA kernelYaxun Liu2018-03-291-0/+11
| | | | | | | | | | | This patch sets target specific calling convention for CUDA kernels in IR. Patch by Greg Rodgers. Revised and lit test added by Yaxun Liu. Differential Revision: https://reviews.llvm.org/D44747 llvm-svn: 328795
* Fix some handling of AST nodes with diagnostics.Richard Trieu2018-03-281-4/+4
| | | | | | | | | The diagnostic system for Clang can already handle many AST nodes. Instead of converting them to strings first, just hand the AST node directly to the diagnostic system and let it handle the output. Minor changes in some diagnostic output. llvm-svn: 328688
* Re-land "[Sema] Make getCurFunction() return null outside function parsing"Reid Kleckner2018-03-121-1/+1
| | | | | | | | | | | | | | This relands r326965. There was a null dereference in typo correction that was triggered in Sema/diagnose_if.c. We are not always in a function scope when doing typo correction. The fix is to add a null check. LLVM's optimizer made it hard to find this bug. I wrote it up in a not-very-well-editted blog post here: http://qinsb.blogspot.com/2018/03/ub-will-delete-your-null-checks.html llvm-svn: 327334
* Revert "[Sema] Make getCurFunction() return null outside function parsing"Reid Kleckner2018-03-081-1/+1
| | | | | | | | | | This reverts r326965. It seems to have caused repeating test failures in clang/test/Sema/diagnose_if.c on some buildbots. I cannot reproduce the problem, and it's not immediately obvious what the problem is, so let's revert to green. llvm-svn: 326974
* [Sema] Make getCurFunction() return null outside function parsingReid Kleckner2018-03-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Summary: Before this patch, Sema pre-allocated a FunctionScopeInfo and kept it in the first, always present element of the FunctionScopes stack. This meant that Sema::getCurFunction would return a pointer to this pre-allocated object when parsing code outside a function body. This is pretty much always a bug, so this patch moves the pre-allocated object into a separate unique_ptr. This should make bugs like PR36536 a lot more obvious. As you can see from this patch, there were a number of places that unconditionally assumed they were always called inside a function. However, there are also many places that null checked the result of getCurFunction(), so I think this is a reasonable direction. Reviewers: rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D44039 llvm-svn: 326965
OpenPOWER on IntegriCloud