[clang-tools-extra] FIX : bugprone-too-small-loop-variable - false-negative when const variable is used as loop bound (PR #81183)
Shourya Goel via cfe-commits
cfe-commits at lists.llvm.org
Fri Feb 9 03:02:18 PST 2024
https://github.com/Sh0g0-1758 updated https://github.com/llvm/llvm-project/pull/81183
>From 88dac6713284ee4f0b7ce73c944f78085412645f Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 01:21:14 +0530
Subject: [PATCH 1/8] Fix : bugprone-too-small-loop-variable
---
.../bugprone/TooSmallLoopVariableCheck.cpp | 12 ++++++------
clang-tools-extra/docs/ReleaseNotes.rst | 3 +++
.../checks/bugprone/too-small-loop-variable.rst | 2 ++
.../checkers/bugprone/too-small-loop-variable.cpp | 12 ++++++++++++
4 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index 8ba8b893e03a6..8f6547f4ea9e6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -81,12 +81,12 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
// We are interested in only those cases when the loop bound is a variable
// value (not const, enum, etc.).
- StatementMatcher LoopBoundMatcher =
- expr(ignoringParenImpCasts(allOf(hasType(isInteger()),
- unless(integerLiteral()),
- unless(hasType(isConstQualified())),
- unless(hasType(enumType())))))
- .bind(LoopUpperBoundName);
+ StatementMatcher LoopBoundMatcher =
+ expr(ignoringParenImpCasts(allOf(hasType(isInteger()),
+ unless(integerLiteral()),
+ unless(allOf(hasType(isConstQualified()), declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(integerLiteral())), isConstexpr(), isConstinit())))))),
+ unless(hasType(enumType())))))
+ .bind(LoopUpperBoundName);
// We use the loop increment expression only to make sure we found the right
// loop variable.
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index e50914aed5f07..17b1349d20db8 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -169,6 +169,9 @@ Miscellaneous
option is specified. Now ``clang-apply-replacements`` applies formatting only with
the option.
+- Fixed incorrect implementation of ``too-small-loop-variable`` check when a const loop
+ variable is initialized with a function declaration.
+
Improvements to include-fixer
-----------------------------
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
index 0f45cc2fe1146..9ee23be45cfea 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
@@ -44,3 +44,5 @@ a larger user input.
for (unsigned i = 0; i < size; ++i) {} // no warning with MagnitudeBitsUpperLimit = 31 on a system where unsigned is 32-bit
for (int i = 0; i < size; ++i) {} // warning with MagnitudeBitsUpperLimit = 31 on a system where int is 32-bit
}
+
+``-Wtautological-constant-out-of-range-compare`` compiler warning should also be used.
\ No newline at end of file
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/too-small-loop-variable.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/too-small-loop-variable.cpp
index 3229deb93bada..113150b168650 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone/too-small-loop-variable.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/too-small-loop-variable.cpp
@@ -93,6 +93,18 @@ void voidBadForLoopWithMacroBound() {
}
}
+unsigned int getVal() {
+ return 300;
+}
+
+// The iteration's upper bound has a function declaration.
+void voidBadForLoop8() {
+ const unsigned int l = getVal();
+ for (unsigned char i = 0; i < l; ++i) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: loop variable has narrower type 'unsigned char' than iteration's upper bound 'const unsigned int' [bugprone-too-small-loop-variable]
+ }
+}
+
////////////////////////////////////////////////////////////////////////////////
/// Correct loops: we should not warn here.
>From 41acf22b481ba6800c1d07e96d1d3ba8052b20a7 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 01:21:39 +0530
Subject: [PATCH 2/8] Ran git clang Formatter
---
.../bugprone/TooSmallLoopVariableCheck.cpp | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index 8f6547f4ea9e6..a73d46f01d9b2 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -81,12 +81,16 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
// We are interested in only those cases when the loop bound is a variable
// value (not const, enum, etc.).
- StatementMatcher LoopBoundMatcher =
- expr(ignoringParenImpCasts(allOf(hasType(isInteger()),
- unless(integerLiteral()),
- unless(allOf(hasType(isConstQualified()), declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(integerLiteral())), isConstexpr(), isConstinit())))))),
- unless(hasType(enumType())))))
- .bind(LoopUpperBoundName);
+ StatementMatcher LoopBoundMatcher =
+ expr(ignoringParenImpCasts(allOf(
+ hasType(isInteger()), unless(integerLiteral()),
+ unless(allOf(
+ hasType(isConstQualified()),
+ declRefExpr(to(varDecl(anyOf(
+ hasInitializer(ignoringParenImpCasts(integerLiteral())),
+ isConstexpr(), isConstinit())))))),
+ unless(hasType(enumType())))))
+ .bind(LoopUpperBoundName);
// We use the loop increment expression only to make sure we found the right
// loop variable.
>From 1a603c40aed5e7352bea68602c418215e2e80351 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 11:49:51 +0530
Subject: [PATCH 3/8] Changed Documentation
---
clang-tools-extra/docs/ReleaseNotes.rst | 7 ++++---
.../clang-tidy/checks/bugprone/too-small-loop-variable.rst | 4 ++--
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 17b1349d20db8..42bcabdcf5692 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -156,6 +156,10 @@ Changes in existing checks
`AllowStringArrays` option, enabling the exclusion of array types with deduced
length initialized from string literals.
+- Improved :doc:`bugprone-too-small-loop-variable
+ <clang-tidy/checks/bugprone/too-small-loop-variable>` check by correctly
+ implementing the check for const loop variables with a function declaration.
+
Removed checks
^^^^^^^^^^^^^^
@@ -169,9 +173,6 @@ Miscellaneous
option is specified. Now ``clang-apply-replacements`` applies formatting only with
the option.
-- Fixed incorrect implementation of ``too-small-loop-variable`` check when a const loop
- variable is initialized with a function declaration.
-
Improvements to include-fixer
-----------------------------
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
index 9ee23be45cfea..9a2e4f6ddd46d 100644
--- a/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/too-small-loop-variable.rst
@@ -28,6 +28,8 @@ In a real use case size means a container's size which depends on the user input
This algorithm works for a small amount of objects, but will lead to freeze for
a larger user input.
+It's recommended to enable the compiler warning -Wtautological-constant-out-of-range-compare as well, since check does not inspect compile-time constant loop boundaries to avoid overlaps with the warning.
+
.. option:: MagnitudeBitsUpperLimit
Upper limit for the magnitude bits of the loop variable. If it's set the check
@@ -44,5 +46,3 @@ a larger user input.
for (unsigned i = 0; i < size; ++i) {} // no warning with MagnitudeBitsUpperLimit = 31 on a system where unsigned is 32-bit
for (int i = 0; i < size; ++i) {} // warning with MagnitudeBitsUpperLimit = 31 on a system where int is 32-bit
}
-
-``-Wtautological-constant-out-of-range-compare`` compiler warning should also be used.
\ No newline at end of file
>From 49f11c1d941769a20f2bb7b33d853939a224289f Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 11:51:47 +0530
Subject: [PATCH 4/8] Changed Doc
---
clang-tools-extra/docs/ReleaseNotes.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 42bcabdcf5692..d8b26d8b195fb 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -158,7 +158,7 @@ Changes in existing checks
- Improved :doc:`bugprone-too-small-loop-variable
<clang-tidy/checks/bugprone/too-small-loop-variable>` check by correctly
- implementing the check for const loop variables with a function declaration.
+ implementing the check for const loop variable initialized with a function declaration.
Removed checks
^^^^^^^^^^^^^^
>From 3c8e3f0e12185645c0509fe338797bde15744c70 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 16:24:11 +0530
Subject: [PATCH 5/8] reduced duplications
---
.../clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index a73d46f01d9b2..c9d99ff7b54a6 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -84,12 +84,9 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
StatementMatcher LoopBoundMatcher =
expr(ignoringParenImpCasts(allOf(
hasType(isInteger()), unless(integerLiteral()),
- unless(allOf(
- hasType(isConstQualified()),
- declRefExpr(to(varDecl(anyOf(
- hasInitializer(ignoringParenImpCasts(integerLiteral())),
- isConstexpr(), isConstinit())))))),
- unless(hasType(enumType())))))
+unless(declRefExpr(to(enumConstantDecl()))),
+unless(allOf(hasType(isConstQualified()),
+ declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(declRefExpr(to(enumConstantDecl())))), isConstexpr(), isConstinit())))))
.bind(LoopUpperBoundName);
// We use the loop increment expression only to make sure we found the right
>From 656f2b482a4994653bf4a935111d1222ac18bec7 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 16:25:30 +0530
Subject: [PATCH 6/8] formatter
---
.../clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index c9d99ff7b54a6..ba92b4500e2f5 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -84,8 +84,8 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
StatementMatcher LoopBoundMatcher =
expr(ignoringParenImpCasts(allOf(
hasType(isInteger()), unless(integerLiteral()),
-unless(declRefExpr(to(enumConstantDecl()))),
-unless(allOf(hasType(isConstQualified()),
+ unless(declRefExpr(to(enumConstantDecl()))),
+ unless(allOf(hasType(isConstQualified()),
declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(declRefExpr(to(enumConstantDecl())))), isConstexpr(), isConstinit())))))
.bind(LoopUpperBoundName);
>From 7c3caa3a906ea1e061c0c2218b5dad0281db43f9 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 16:26:45 +0530
Subject: [PATCH 7/8] Colon addition
---
.../clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index ba92b4500e2f5..720c01edfd54d 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -86,7 +86,7 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
hasType(isInteger()), unless(integerLiteral()),
unless(declRefExpr(to(enumConstantDecl()))),
unless(allOf(hasType(isConstQualified()),
- declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(declRefExpr(to(enumConstantDecl())))), isConstexpr(), isConstinit())))))
+ declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(declRefExpr(to(enumConstantDecl())))), isConstexpr(), isConstinit())))))))))
.bind(LoopUpperBoundName);
// We use the loop increment expression only to make sure we found the right
>From c8f6a406702a1e72664241c9e58dde85a305ed73 Mon Sep 17 00:00:00 2001
From: Sh0g0-1758 <shouryagoel10000 at gmail.com>
Date: Fri, 9 Feb 2024 16:27:07 +0530
Subject: [PATCH 8/8] Ran git clang Formatter
---
.../bugprone/TooSmallLoopVariableCheck.cpp | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
index 720c01edfd54d..031c9ebc53a74 100644
--- a/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/TooSmallLoopVariableCheck.cpp
@@ -82,11 +82,14 @@ void TooSmallLoopVariableCheck::registerMatchers(MatchFinder *Finder) {
// We are interested in only those cases when the loop bound is a variable
// value (not const, enum, etc.).
StatementMatcher LoopBoundMatcher =
- expr(ignoringParenImpCasts(allOf(
- hasType(isInteger()), unless(integerLiteral()),
- unless(declRefExpr(to(enumConstantDecl()))),
- unless(allOf(hasType(isConstQualified()),
- declRefExpr(to(varDecl(anyOf(hasInitializer(ignoringParenImpCasts(declRefExpr(to(enumConstantDecl())))), isConstexpr(), isConstinit())))))))))
+ expr(ignoringParenImpCasts(
+ allOf(hasType(isInteger()), unless(integerLiteral()),
+ unless(declRefExpr(to(enumConstantDecl()))),
+ unless(allOf(hasType(isConstQualified()),
+ declRefExpr(to(varDecl(anyOf(
+ hasInitializer(ignoringParenImpCasts(
+ declRefExpr(to(enumConstantDecl())))),
+ isConstexpr(), isConstinit())))))))))
.bind(LoopUpperBoundName);
// We use the loop increment expression only to make sure we found the right
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