bd77e9acf0
This commit is a re-do of e4a8969e56572371201863594b3a549de2e23f32, which got reverted, with the same goal: dramatically speed-up clang-tidy by avoiding doing work in system headers (which is wasteful as warnings are later discarded). This proposal was already discussed here with favorable feedback: https://github.com/llvm/llvm-project/pull/132725 The novelty of this patch is: - It's less aggressive: it does not fiddle with AST traversal. This solves the issue with the previous patch, which impacted the ability to inspect parents of a given node. - Instead, what we optimize for is exitting early in each `Traverse*` function of `MatchASTVisitor` if the node is in a system header, thus avoiding calling the `match()` function with its corresponding callback (when there is a match). - It does not cause any failing tests. - It does not move `MatchFinderOptions` - instead we add a user-defined default constructor which solves the same problem. - It introduces a function `shouldSkipNode` which can be extended for adding more conditions. For example there's a PR open about skipping modules in clang-tidy where this could come handy: https://github.com/llvm/llvm-project/pull/145630 As a benchmark, I ran clang-tidy with all checks activated, on a single .cpp file which #includes all the standard C++ headers, then measure the time as well as found warnings. On trunk: ``` Suppressed 75413 warnings (75413 in non-user code). real 0m12.418s user 0m12.270s sys 0m0.129s ``` With this patch: ``` Suppressed 11448 warnings (11448 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. real 0m1.666s user 0m1.538s sys 0m0.129s ``` With the original patch that got reverted: ``` Suppressed 11428 warnings (11428 in non-user code). real 0m1.193s user 0m1.096s sys 0m0.096s ``` We therefore get a dramatic reduction in number of warnings and runtime, with no change in functionality. The remaining warnings are due to `PPCallbacks` - implementing a similar system-header exclusion mechanism there can lead to almost no warnings left in system headers. This does not bring the runtime down as much, though, so it's probably not worth the effort. Fixes #52959 Co-authored-by: Carlos Gálvez <carlos.galvez@zenseact.com>
25 lines
2.3 KiB
C++
25 lines
2.3 KiB
C++
// RUN: clang-tidy -dump-config -system-headers=true | FileCheck -check-prefix=CHECK-CONFIG-SYSTEM-HEADERS %s
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// RUN: clang-tidy -dump-config -system-headers=false | FileCheck -check-prefix=CHECK-CONFIG-NO-SYSTEM-HEADERS %s
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// RUN: clang-tidy -config='SystemHeaders: true' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-SYSTEM-HEADERS %s
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// RUN: clang-tidy -config='SystemHeaders: false' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-NO-SYSTEM-HEADERS %s
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// RUN: clang-tidy -system-headers=true -config='SystemHeaders: true' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-SYSTEM-HEADERS %s
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// RUN: clang-tidy -system-headers=true -config='SystemHeaders: false' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-SYSTEM-HEADERS %s
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// RUN: clang-tidy -system-headers=false -config='SystemHeaders: true' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-NO-SYSTEM-HEADERS %s
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// RUN: clang-tidy -system-headers=false -config='SystemHeaders: false' -dump-config | FileCheck -check-prefix=CHECK-CONFIG-NO-SYSTEM-HEADERS %s
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// RUN: clang-tidy -help | FileCheck -check-prefix=CHECK-OPT-PRESENT %s
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// RUN: clang-tidy -checks='-*,google-explicit-constructor' -header-filter='.*' -system-headers=true %s -- -isystem %S/Inputs/system-headers 2>&1 | FileCheck -check-prefix=CHECK-SYSTEM-HEADERS %s
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// RUN: clang-tidy -checks='-*,google-explicit-constructor' -header-filter='.*' -system-headers=false %s -- -isystem %S/Inputs/system-headers 2>&1 | FileCheck -check-prefix=CHECK-NO-SYSTEM-HEADERS --allow-empty %s
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// RUN: clang-tidy -checks='-*,google-explicit-constructor' -header-filter='.*' -config='SystemHeaders: true' %s -- -isystem %S/Inputs/system-headers 2>&1 | FileCheck -check-prefix=CHECK-SYSTEM-HEADERS %s
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// RUN: clang-tidy -checks='-*,google-explicit-constructor' -header-filter='.*' -config='SystemHeaders: false' %s -- -isystem %S/Inputs/system-headers 2>&1 | FileCheck -check-prefix=CHECK-NO-SYSTEM-HEADERS --allow-empty %s
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#include <system_header.h>
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// CHECK-SYSTEM-HEADERS: system_header.h:1:13: warning: single-argument constructors must be marked explicit
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// CHECK-NO-SYSTEM-HEADERS-NOT: system_header.h:1:13: warning: single-argument constructors must be marked explicit
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// CHECK-CONFIG-NO-SYSTEM-HEADERS: SystemHeaders: false
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// CHECK-CONFIG-SYSTEM-HEADERS: SystemHeaders: true
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// CHECK-OPT-PRESENT: --system-headers
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