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2025-08-26[clang] NFC: introduce Type::getAsEnumDecl, and cast variants for all ↵Matheus Izvekov
TagDecls (#155463) And make use of those. These changes are split from prior PR #155028, in order to decrease the size of that PR and facilitate review.
2025-08-09[clang] Improve nested name specifier AST representation (#147835)Matheus Izvekov
This is a major change on how we represent nested name qualifications in the AST. * The nested name specifier itself and how it's stored is changed. The prefixes for types are handled within the type hierarchy, which makes canonicalization for them super cheap, no memory allocation required. Also translating a type into nested name specifier form becomes a no-op. An identifier is stored as a DependentNameType. The nested name specifier gains a lightweight handle class, to be used instead of passing around pointers, which is similar to what is implemented for TemplateName. There is still one free bit available, and this handle can be used within a PointerUnion and PointerIntPair, which should keep bit-packing aficionados happy. * The ElaboratedType node is removed, all type nodes in which it could previously apply to can now store the elaborated keyword and name qualifier, tail allocating when present. * TagTypes can now point to the exact declaration found when producing these, as opposed to the previous situation of there only existing one TagType per entity. This increases the amount of type sugar retained, and can have several applications, for example in tracking module ownership, and other tools which care about source file origins, such as IWYU. These TagTypes are lazily allocated, in order to limit the increase in AST size. This patch offers a great performance benefit. It greatly improves compilation time for [stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for `test_on2.cpp` in that project, which is the slowest compiling test, this patch improves `-c` compilation time by about 7.2%, with the `-fsyntax-only` improvement being at ~12%. This has great results on compile-time-tracker as well: ![image](https://github.com/user-attachments/assets/700dce98-2cab-4aa8-97d1-b038c0bee831) This patch also further enables other optimziations in the future, and will reduce the performance impact of template specialization resugaring when that lands. It has some other miscelaneous drive-by fixes. About the review: Yes the patch is huge, sorry about that. Part of the reason is that I started by the nested name specifier part, before the ElaboratedType part, but that had a huge performance downside, as ElaboratedType is a big performance hog. I didn't have the steam to go back and change the patch after the fact. There is also a lot of internal API changes, and it made sense to remove ElaboratedType in one go, versus removing it from one type at a time, as that would present much more churn to the users. Also, the nested name specifier having a different API avoids missing changes related to how prefixes work now, which could make existing code compile but not work. How to review: The important changes are all in `clang/include/clang/AST` and `clang/lib/AST`, with also important changes in `clang/lib/Sema/TreeTransform.h`. The rest and bulk of the changes are mostly consequences of the changes in API. PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just for easier to rebasing. I plan to rename it back after this lands. Fixes #136624 Fixes https://github.com/llvm/llvm-project/issues/43179 Fixes https://github.com/llvm/llvm-project/issues/68670 Fixes https://github.com/llvm/llvm-project/issues/92757
2025-07-19Reland [Clang] Make the SizeType, SignedSizeType and PtrdiffType be named ↵YexuanXiao
sugar types (#149613) The checks for the 'z' and 't' format specifiers added in the original PR #143653 had some issues and were overly strict, causing some build failures and were consequently reverted at https://github.com/llvm/llvm-project/commit/4c85bf2fe8042c855c9dd5be4b02191e9d071ffd. In the latest commit https://github.com/llvm/llvm-project/pull/149613/commits/27c58629ec76a703fde9c0b99b170573170b4a7a, I relaxed the checks for the 'z' and 't' format specifiers, so warnings are now only issued when they are used with mismatched types. The original intent of these checks was to diagnose code that assumes the underlying type of `size_t` is `unsigned` or `unsigned long`, for example: ```c printf("%zu", 1ul); // Not portable, but not an error when size_t is unsigned long ``` However, it produced a significant number of false positives. This was partly because Clang does not treat the `typedef` `size_t` and `__size_t` as having a common "sugar" type, and partly because a large amount of existing code either assumes `unsigned` (or `unsigned long`) is `size_t`, or they define the equivalent of size_t in their own way (such as sanitizer_internal_defs.h).https://github.com/llvm/llvm-project/blob/2e67dcfdcd023df2f06e0823eeea23990ce41534/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h#L203
2025-07-17Revert "[Clang] Make the SizeType, SignedSizeType and PtrdiffType be named ↵Kazu Hirata
sugar types instead of built-in types (#143653)" This reverts commit c27e283cfbca2bd22f34592430e98ee76ed60ad8. A builbot failure has been reported: https://lab.llvm.org/buildbot/#/builders/186/builds/10819/steps/10/logs/stdio I'm also getting a large number of warnings related to %zu and %zx.
2025-07-17[Clang] Make the SizeType, SignedSizeType and PtrdiffType be named sugar ↵YexuanXiao
types instead of built-in types (#143653) Including the results of `sizeof`, `sizeof...`, `__datasizeof`, `__alignof`, `_Alignof`, `alignof`, `_Countof`, `size_t` literals, and signed `size_t` literals, the results of pointer-pointer subtraction and checks for standard library functions (and their calls). The goal is to enable clang and downstream tools such as clangd and clang-tidy to provide more portable hints and diagnostics. The previous discussion can be found at #136542. This PR implements this feature by introducing a new subtype of `Type` called `PredefinedSugarType`, which was considered appropriate in discussions. I tried to keep `PredefinedSugarType` simple enough yet not limited to `size_t` and `ptrdiff_t` so that it can be used for other purposes. `PredefinedSugarType` wraps a canonical `Type` and provides a name, conceptually similar to a compiler internal `TypedefType` but without depending on a `TypedefDecl` or a source file. Additionally, checks for the `z` and `t` format specifiers in format strings for `scanf` and `printf` were added. It will precisely match expressions using `typedef`s or built-in expressions. The affected tests indicates that it works very well. Several code require that `SizeType` is canonical, so I kept `SizeType` to its canonical form. The failed tests in CI are allowed to fail. See the [comment](https://github.com/llvm/llvm-project/pull/135386#issuecomment-3049426611) in another PR #135386.
2024-03-26[NFC] Refactor ConstantArrayType size storage (#85716)Chris B
In PR #79382, I need to add a new type that derives from ConstantArrayType. This means that ConstantArrayType can no longer use `llvm::TrailingObjects` to store the trailing optional Expr*. This change refactors ConstantArrayType to store a 60-bit integer and 4-bits for the integer size in bytes. This replaces the APInt field previously in the type but preserves enough information to recreate it where needed. To reduce the number of places where the APInt is re-constructed I've also added some helper methods to the ConstantArrayType to allow some common use cases that operate on either the stored small integer or the APInt as appropriate. Resolves #85124.
2023-10-31[clang][NFC] Refactor `ArrayType::ArraySizeModifier`Vlad Serebrennikov
This patch moves `ArraySizeModifier` before `Type` declaration so that it's complete at `ArrayTypeBitfields` declaration. It's also converted to scoped enum along the way.
2022-08-08[clang] LLVM_FALLTHROUGH => [[fallthrough]]. NFCFangrui Song
With C++17 there is no Clang pedantic warning or MSVC C5051. Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D131346
2022-08-04[Sema] -Wformat: support C23 format specifier %b %BFangrui Song
Close #56885: WG14 N2630 added %b to fprintf/fscanf and recommended %B for fprintf. This patch teaches -Wformat %b for the printf/scanf family of functions and %B for the printf family of functions. glibc 2.35 and latest Android bionic added %b/%B printf support. From https://www.openwall.com/lists/libc-coord/2022/07/ no scanf support is available yet. Like GCC, we don't test library support. GCC 12 -Wformat -pedantic emits a warning: > warning: ISO C17 does not support the ‘%b’ gnu_printf format [-Wformat=] The behavior is not ported. Note: `freebsd_kernel_printf` uses %b differently. Reviewed By: aaron.ballman, dim, enh Differential Revision: https://reviews.llvm.org/D131057
2022-07-27[clang] Implement ElaboratedType sugaring for types written bareMatheus Izvekov
Without this patch, clang will not wrap in an ElaboratedType node types written without a keyword and nested name qualifier, which goes against the intent that we should produce an AST which retains enough details to recover how things are written. The lack of this sugar is incompatible with the intent of the type printer default policy, which is to print types as written, but to fall back and print them fully qualified when they are desugared. An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still requires pointer alignment due to pre-existing bug in the TypeLoc buffer handling. --- Troubleshooting list to deal with any breakage seen with this patch: 1) The most likely effect one would see by this patch is a change in how a type is printed. The type printer will, by design and default, print types as written. There are customization options there, but not that many, and they mainly apply to how to print a type that we somehow failed to track how it was written. This patch fixes a problem where we failed to distinguish between a type that was written without any elaborated-type qualifiers, such as a 'struct'/'class' tags and name spacifiers such as 'std::', and one that has been stripped of any 'metadata' that identifies such, the so called canonical types. Example: ``` namespace foo { struct A {}; A a; }; ``` If one were to print the type of `foo::a`, prior to this patch, this would result in `foo::A`. This is how the type printer would have, by default, printed the canonical type of A as well. As soon as you add any name qualifiers to A, the type printer would suddenly start accurately printing the type as written. This patch will make it print it accurately even when written without qualifiers, so we will just print `A` for the initial example, as the user did not really write that `foo::` namespace qualifier. 2) This patch could expose a bug in some AST matcher. Matching types is harder to get right when there is sugar involved. For example, if you want to match a type against being a pointer to some type A, then you have to account for getting a type that is sugar for a pointer to A, or being a pointer to sugar to A, or both! Usually you would get the second part wrong, and this would work for a very simple test where you don't use any name qualifiers, but you would discover is broken when you do. The usual fix is to either use the matcher which strips sugar, which is annoying to use as for example if you match an N level pointer, you have to put N+1 such matchers in there, beginning to end and between all those levels. But in a lot of cases, if the property you want to match is present in the canonical type, it's easier and faster to just match on that... This goes with what is said in 1), if you want to match against the name of a type, and you want the name string to be something stable, perhaps matching on the name of the canonical type is the better choice. 3) This patch could expose a bug in how you get the source range of some TypeLoc. For some reason, a lot of code is using getLocalSourceRange(), which only looks at the given TypeLoc node. This patch introduces a new, and more common TypeLoc node which contains no source locations on itself. This is not an inovation here, and some other, more rare TypeLoc nodes could also have this property, but if you use getLocalSourceRange on them, it's not going to return any valid locations, because it doesn't have any. The right fix here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive into the inner TypeLoc to get the source range if it doesn't find it on the top level one. You can use getLocalSourceRange if you are really into micro-optimizations and you have some outside knowledge that the TypeLocs you are dealing with will always include some source location. 4) Exposed a bug somewhere in the use of the normal clang type class API, where you have some type, you want to see if that type is some particular kind, you try a `dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match. Again, like 2), this would usually have been tested poorly with some simple tests with no qualifications, and would have been broken had there been any other kind of type sugar, be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType. The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper into the type. Or use `getAsAdjusted` when dealing with TypeLocs. For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast. 5) It could be a bug in this patch perhaps. Let me know if you need any help! Signed-off-by: Matheus Izvekov <mizvekov@gmail.com> Differential Revision: https://reviews.llvm.org/D112374
2022-07-14Revert "[clang] Implement ElaboratedType sugaring for types written bare"Jonas Devlieghere
This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it stills breaks the LLDB tests. This was re-landed without addressing the issue or even agreement on how to address the issue. More details and discussion in https://reviews.llvm.org/D112374.
2022-07-15[clang] Implement ElaboratedType sugaring for types written bareMatheus Izvekov
Without this patch, clang will not wrap in an ElaboratedType node types written without a keyword and nested name qualifier, which goes against the intent that we should produce an AST which retains enough details to recover how things are written. The lack of this sugar is incompatible with the intent of the type printer default policy, which is to print types as written, but to fall back and print them fully qualified when they are desugared. An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still requires pointer alignment due to pre-existing bug in the TypeLoc buffer handling. --- Troubleshooting list to deal with any breakage seen with this patch: 1) The most likely effect one would see by this patch is a change in how a type is printed. The type printer will, by design and default, print types as written. There are customization options there, but not that many, and they mainly apply to how to print a type that we somehow failed to track how it was written. This patch fixes a problem where we failed to distinguish between a type that was written without any elaborated-type qualifiers, such as a 'struct'/'class' tags and name spacifiers such as 'std::', and one that has been stripped of any 'metadata' that identifies such, the so called canonical types. Example: ``` namespace foo { struct A {}; A a; }; ``` If one were to print the type of `foo::a`, prior to this patch, this would result in `foo::A`. This is how the type printer would have, by default, printed the canonical type of A as well. As soon as you add any name qualifiers to A, the type printer would suddenly start accurately printing the type as written. This patch will make it print it accurately even when written without qualifiers, so we will just print `A` for the initial example, as the user did not really write that `foo::` namespace qualifier. 2) This patch could expose a bug in some AST matcher. Matching types is harder to get right when there is sugar involved. For example, if you want to match a type against being a pointer to some type A, then you have to account for getting a type that is sugar for a pointer to A, or being a pointer to sugar to A, or both! Usually you would get the second part wrong, and this would work for a very simple test where you don't use any name qualifiers, but you would discover is broken when you do. The usual fix is to either use the matcher which strips sugar, which is annoying to use as for example if you match an N level pointer, you have to put N+1 such matchers in there, beginning to end and between all those levels. But in a lot of cases, if the property you want to match is present in the canonical type, it's easier and faster to just match on that... This goes with what is said in 1), if you want to match against the name of a type, and you want the name string to be something stable, perhaps matching on the name of the canonical type is the better choice. 3) This patch could exposed a bug in how you get the source range of some TypeLoc. For some reason, a lot of code is using getLocalSourceRange(), which only looks at the given TypeLoc node. This patch introduces a new, and more common TypeLoc node which contains no source locations on itself. This is not an inovation here, and some other, more rare TypeLoc nodes could also have this property, but if you use getLocalSourceRange on them, it's not going to return any valid locations, because it doesn't have any. The right fix here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive into the inner TypeLoc to get the source range if it doesn't find it on the top level one. You can use getLocalSourceRange if you are really into micro-optimizations and you have some outside knowledge that the TypeLocs you are dealing with will always include some source location. 4) Exposed a bug somewhere in the use of the normal clang type class API, where you have some type, you want to see if that type is some particular kind, you try a `dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match. Again, like 2), this would usually have been tested poorly with some simple tests with no qualifications, and would have been broken had there been any other kind of type sugar, be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType. The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper into the type. Or use `getAsAdjusted` when dealing with TypeLocs. For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast. 5) It could be a bug in this patch perhaps. Let me know if you need any help! Signed-off-by: Matheus Izvekov <mizvekov@gmail.com> Differential Revision: https://reviews.llvm.org/D112374
2022-07-13Revert "[clang] Implement ElaboratedType sugaring for types written bare"Jonas Devlieghere
This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it breaks all the LLDB tests that import the std module. import-std-module/array.TestArrayFromStdModule.py import-std-module/deque-basic.TestDequeFromStdModule.py import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py import-std-module/forward_list.TestForwardListFromStdModule.py import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py import-std-module/list.TestListFromStdModule.py import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py import-std-module/queue.TestQueueFromStdModule.py import-std-module/stack.TestStackFromStdModule.py import-std-module/vector.TestVectorFromStdModule.py import-std-module/vector-bool.TestVectorBoolFromStdModule.py import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/
2022-07-13[clang] Implement ElaboratedType sugaring for types written bareMatheus Izvekov
Without this patch, clang will not wrap in an ElaboratedType node types written without a keyword and nested name qualifier, which goes against the intent that we should produce an AST which retains enough details to recover how things are written. The lack of this sugar is incompatible with the intent of the type printer default policy, which is to print types as written, but to fall back and print them fully qualified when they are desugared. An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still requires pointer alignment due to pre-existing bug in the TypeLoc buffer handling. Signed-off-by: Matheus Izvekov <mizvekov@gmail.com> Differential Revision: https://reviews.llvm.org/D112374
2019-07-16Fix parameter name comments using clang-tidy. NFC.Rui Ueyama
This patch applies clang-tidy's bugprone-argument-comment tool to LLVM, clang and lld source trees. Here is how I created this patch: $ git clone https://github.com/llvm/llvm-project.git $ cd llvm-project $ mkdir build $ cd build $ cmake -GNinja -DCMAKE_BUILD_TYPE=Debug \ -DLLVM_ENABLE_PROJECTS='clang;lld;clang-tools-extra' \ -DCMAKE_EXPORT_COMPILE_COMMANDS=On -DLLVM_ENABLE_LLD=On \ -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ../llvm $ ninja $ parallel clang-tidy -checks='-*,bugprone-argument-comment' \ -config='{CheckOptions: [{key: StrictMode, value: 1}]}' -fix \ ::: ../llvm/lib/**/*.{cpp,h} ../clang/lib/**/*.{cpp,h} ../lld/**/*.{cpp,h} llvm-svn: 366177
2019-01-29OpenCL: Use length modifier for warning on vector printf argumentsMatt Arsenault
Re-enable format string warnings on printf. The warnings are still incomplete. Apparently it is undefined to use a vector specifier without a length modifier, which is not currently warned on. Additionally, type warnings appear to not be working with the hh modifier, and aren't warning on all of the special restrictions from c99 printf. llvm-svn: 352540
2019-01-19Update the file headers across all of the LLVM projects in the monorepoChandler Carruth
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
2019-01-11Fix a pair of Wfallthrough warnings in ScanfFormatString.Erich Keane
Change-Id: Ia73a34fdd93fc974224583505f9e6432493cb0da llvm-svn: 350941
2018-11-02Reapply Logging: make os_log buffer size an integer constant expression.Tim Northover
The size of an os_log buffer is known at any stage of compilation, so making it a constant expression means that the common idiom of declaring a buffer for it won't result in a VLA. That allows the compiler to skip saving and restoring the stack pointer around such buffers. This also moves the OSLog and other FormatString helpers from libclangAnalysis to libclangAST to avoid a circular dependency. llvm-svn: 345971