jubnzv created this revision.
jubnzv added reviewers: steakhal, NoQ, vsavchenko, Szelethus, xazax.hun,
balazske.
jubnzv added a project: clang.
Herald added subscribers: manas, ASDenysPetrov, martong, dkrupp, donat.nagy,
mikhail.ramalho, a.sidorin, rnkovacs, szepet, baloghadamsoftware.
jubnzv requested review of this revision.
Fix offset calculation routines in padding checker to avoid assertion errors
described in the following issue: https://bugs.llvm.org/show_bug.cgi?id=50426.
The fields that are subojbects of zero size, marked with [[no_unique_address]]
or empty bitfields will be excluded from the padding calculation routines.
https://reviews.llvm.org/D104097
Files:
clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
clang/test/Analysis/padding_cpp.cpp
Index: clang/test/Analysis/padding_cpp.cpp
===================================================================
--- clang/test/Analysis/padding_cpp.cpp
+++ clang/test/Analysis/padding_cpp.cpp
@@ -200,3 +200,17 @@
// expected-warning@+1{{Excessive padding in 'class (lambda}}
auto lambda1 = [ c1 = G.c1, i = G.i, c2 = G.c2 ]{};
auto lambda2 = [ i = G.i, c1 = G.c1, c2 = G.c2 ]{}; // no-warning
+
+// expected-warning@+1{{Excessive padding in 'struct NoUniqueAddressWarn' (6
padding}}
+struct NoUniqueAddressWarn {
+ char c1;
+ [[no_unique_address]] Empty empty;
+ int i;
+ char c2;
+};
+
+struct NoUniqueAddressNoWarn { // no-warning
+ char c1;
+ [[no_unique_address]] Empty empty;
+ char c2;
+};
Index: clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
@@ -193,6 +193,11 @@
CharUnits PaddingSum;
CharUnits Offset = ASTContext.toCharUnitsFromBits(RL.getFieldOffset(0));
for (const FieldDecl *FD : RD->fields()) {
+ // Skip field that is a subobject of zero size, marked with
+ // [[no_unique_address]] or an empty bitfield, because its address can be
+ // set the same as the other fields addresses.
+ if (FD->isZeroSize(ASTContext))
+ continue;
// This checker only cares about the padded size of the
// field, and not the data size. If the field is a record
// with tail padding, then we won't put that number in our
@@ -249,7 +254,7 @@
RetVal.Field = FD;
auto &Ctx = FD->getASTContext();
auto Info = Ctx.getTypeInfoInChars(FD->getType());
- RetVal.Size = Info.Width;
+ RetVal.Size = FD->isZeroSize(Ctx) ? CharUnits::Zero() : Info.Width;
RetVal.Align = Info.Align;
assert(llvm::isPowerOf2_64(RetVal.Align.getQuantity()));
if (auto Max = FD->getMaxAlignment())
Index: clang/test/Analysis/padding_cpp.cpp
===================================================================
--- clang/test/Analysis/padding_cpp.cpp
+++ clang/test/Analysis/padding_cpp.cpp
@@ -200,3 +200,17 @@
// expected-warning@+1{{Excessive padding in 'class (lambda}}
auto lambda1 = [ c1 = G.c1, i = G.i, c2 = G.c2 ]{};
auto lambda2 = [ i = G.i, c1 = G.c1, c2 = G.c2 ]{}; // no-warning
+
+// expected-warning@+1{{Excessive padding in 'struct NoUniqueAddressWarn' (6 padding}}
+struct NoUniqueAddressWarn {
+ char c1;
+ [[no_unique_address]] Empty empty;
+ int i;
+ char c2;
+};
+
+struct NoUniqueAddressNoWarn { // no-warning
+ char c1;
+ [[no_unique_address]] Empty empty;
+ char c2;
+};
Index: clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/PaddingChecker.cpp
@@ -193,6 +193,11 @@
CharUnits PaddingSum;
CharUnits Offset = ASTContext.toCharUnitsFromBits(RL.getFieldOffset(0));
for (const FieldDecl *FD : RD->fields()) {
+ // Skip field that is a subobject of zero size, marked with
+ // [[no_unique_address]] or an empty bitfield, because its address can be
+ // set the same as the other fields addresses.
+ if (FD->isZeroSize(ASTContext))
+ continue;
// This checker only cares about the padded size of the
// field, and not the data size. If the field is a record
// with tail padding, then we won't put that number in our
@@ -249,7 +254,7 @@
RetVal.Field = FD;
auto &Ctx = FD->getASTContext();
auto Info = Ctx.getTypeInfoInChars(FD->getType());
- RetVal.Size = Info.Width;
+ RetVal.Size = FD->isZeroSize(Ctx) ? CharUnits::Zero() : Info.Width;
RetVal.Align = Info.Align;
assert(llvm::isPowerOf2_64(RetVal.Align.getQuantity()));
if (auto Max = FD->getMaxAlignment())
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