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-rw-r--r--INPUTS/cfg-nested-var-scopes.cpp59
-rw-r--r--include/clang/Analysis/CFG.h4
-rw-r--r--lib/Analysis/CFG.cpp89
-rw-r--r--test/SemaCXX/return-noreturn.cpp58
4 files changed, 181 insertions, 29 deletions
diff --git a/INPUTS/cfg-nested-var-scopes.cpp b/INPUTS/cfg-nested-var-scopes.cpp
new file mode 100644
index 0000000000..0944ec268f
--- /dev/null
+++ b/INPUTS/cfg-nested-var-scopes.cpp
@@ -0,0 +1,59 @@
+// Hammer the CFG with large numbers of overlapping variable scopes, which
+// implicit destructors triggered at each edge.
+
+#define EXPAND_BASIC_STRUCT(i) struct X##i { X##i(int); ~X##i(); };
+#define EXPAND_NORET_STRUCT(i) struct X##i { X##i(int); ~X##i() __attribute__((noreturn)); };
+EXPAND_BASIC_STRUCT(0000); EXPAND_NORET_STRUCT(0001);
+EXPAND_BASIC_STRUCT(0010); EXPAND_BASIC_STRUCT(0011);
+EXPAND_BASIC_STRUCT(0100); EXPAND_NORET_STRUCT(0101);
+EXPAND_NORET_STRUCT(0110); EXPAND_BASIC_STRUCT(0111);
+EXPAND_BASIC_STRUCT(1000); EXPAND_NORET_STRUCT(1001);
+EXPAND_BASIC_STRUCT(1010); EXPAND_BASIC_STRUCT(1011);
+EXPAND_NORET_STRUCT(1100); EXPAND_NORET_STRUCT(1101);
+EXPAND_BASIC_STRUCT(1110); EXPAND_BASIC_STRUCT(1111);
+
+#define EXPAND_2_VARS(c, i, x) const X##i var_##c##_##i##0(x), &var_##c##_##i##1 = X##i(x)
+#define EXPAND_4_VARS(c, i, x) EXPAND_2_VARS(c, i##0, x); EXPAND_2_VARS(c, i##1, x)
+#define EXPAND_8_VARS(c, i, x) EXPAND_4_VARS(c, i##0, x); EXPAND_4_VARS(c, i##1, x)
+#define EXPAND_16_VARS(c, i, x) EXPAND_8_VARS(c, i##0, x); EXPAND_8_VARS(c, i##1, x)
+#define EXPAND_32_VARS(c, x) EXPAND_16_VARS(c, 0, x); EXPAND_16_VARS(c, 1, x)
+
+#define EXPAND_2_INNER_CASES(i, x, y) INNER_CASE(i, x, y); INNER_CASE(i + 1, x, y);
+#define EXPAND_4_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i, x, y) EXPAND_2_INNER_CASES(i + 2, x, y)
+#define EXPAND_8_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i, x, y) EXPAND_4_INNER_CASES(i + 4, x, y)
+#define EXPAND_16_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i, x, y) EXPAND_8_INNER_CASES(i + 8, x, y)
+#define EXPAND_32_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i, x, y) EXPAND_16_INNER_CASES(i + 16, x, y)
+
+#define EXPAND_2_OUTER_CASES(i, x, y) OUTER_CASE(i, x, y); OUTER_CASE(i + 1, x, y);
+#define EXPAND_4_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i, x, y) EXPAND_2_OUTER_CASES(i + 2, x, y)
+#define EXPAND_8_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i, x, y) EXPAND_4_OUTER_CASES(i + 4, x, y)
+#define EXPAND_16_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i, x, y) EXPAND_8_OUTER_CASES(i + 8, x, y)
+#define EXPAND_32_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i, x, y) EXPAND_16_OUTER_CASES(i + 16, x, y)
+
+unsigned cfg_nested_vars(int x) {
+ int y = 0;
+ while (x > 0) {
+ EXPAND_32_VARS(a, x);
+ switch (x) {
+#define INNER_CASE(i, x, y) \
+ case i: { \
+ int case_var = 3*x + i; \
+ EXPAND_32_VARS(c, case_var); \
+ y += case_var - 1; \
+ break; \
+ }
+#define OUTER_CASE(i, x, y) \
+ case i: { \
+ int case_var = y >> 8; \
+ EXPAND_32_VARS(b, y); \
+ switch (case_var) { \
+ EXPAND_32_INNER_CASES(0, x, y); \
+ } \
+ break; \
+ }
+EXPAND_32_OUTER_CASES(0, x, y);
+ }
+ --x;
+ }
+ return y;
+}
diff --git a/include/clang/Analysis/CFG.h b/include/clang/Analysis/CFG.h
index d395e0078a..f380012080 100644
--- a/include/clang/Analysis/CFG.h
+++ b/include/clang/Analysis/CFG.h
@@ -506,6 +506,10 @@ public:
Elements.push_back(CFGTemporaryDtor(E), C);
}
+ void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C) {
+ Elements.push_back(CFGAutomaticObjDtor(VD, S), C);
+ }
+
// Destructors must be inserted in reversed order. So insertion is in two
// steps. First we prepare space for some number of elements, then we insert
// the elements beginning at the last position in prepared space.
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index d385420a56..69399f3bcd 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -413,11 +413,10 @@ private:
void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
}
+ void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
+ B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
+ }
- void insertAutomaticObjDtors(CFGBlock *Blk, CFGBlock::iterator I,
- LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt *S);
- void appendAutomaticObjDtors(CFGBlock *Blk, LocalScope::const_iterator B,
- LocalScope::const_iterator E, Stmt *S);
void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
LocalScope::const_iterator B, LocalScope::const_iterator E);
@@ -647,8 +646,40 @@ void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
if (B == E)
return;
- autoCreateBlock();
- appendAutomaticObjDtors(Block, B, E, S);
+ CFGBlock::iterator InsertPos;
+
+ // We need to append the destructors in reverse order, but any one of them
+ // may be a no-return destructor which changes the CFG. As a result, buffer
+ // this sequence up and replay them in reverse order when appending onto the
+ // CFGBlock(s).
+ SmallVector<VarDecl*, 10> Decls;
+ Decls.reserve(B.distance(E));
+ for (LocalScope::const_iterator I = B; I != E; ++I)
+ Decls.push_back(*I);
+
+ for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
+ E = Decls.rend();
+ I != E; ++I) {
+ // If this destructor is marked as a no-return destructor, we need to
+ // create a new block for the destructor which does not have as a successor
+ // anything built thus far: control won't flow out of this block.
+ QualType Ty = (*I)->getType().getNonReferenceType();
+ if (const ArrayType *AT = Context->getAsArrayType(Ty))
+ Ty = AT->getElementType();
+ const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor();
+ if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) {
+ Block = createBlock(/*add_successor=*/false);
+ // Wire up this block directly to the exit block if we're in the
+ // no-return case. We pruned any other successors because control flow
+ // won't actually exit this block, but we want to be able to find all of
+ // these entries in the CFG when doing analyses.
+ addSuccessor(Block, &cfg->getExit());
+ } else {
+ autoCreateBlock();
+ }
+
+ appendAutomaticObjDtor(Block, *I, S);
+ }
}
/// addImplicitDtorsForDestructor - Add implicit destructors generated for
@@ -807,34 +838,21 @@ void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
addAutomaticObjDtors(ScopePos, scopeBeginPos, S);
}
-/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with
-/// automatic storage duration to CFGBlock's elements vector. Insertion will be
-/// performed in place specified with iterator.
-void CFGBuilder::insertAutomaticObjDtors(CFGBlock *Blk, CFGBlock::iterator I,
- LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt *S) {
- BumpVectorContext &C = cfg->getBumpVectorContext();
- I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C);
- while (B != E)
- I = Blk->insertAutomaticObjDtor(I, *B++, S);
-}
-
-/// appendAutomaticObjDtors - Append destructor CFGElements for variables with
-/// automatic storage duration to CFGBlock's elements vector. Elements will be
-/// appended to physical end of the vector which happens to be logical
-/// beginning.
-void CFGBuilder::appendAutomaticObjDtors(CFGBlock *Blk,
- LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt *S) {
- insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S);
-}
-
/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
/// variables with automatic storage duration to CFGBlock's elements vector.
/// Elements will be prepended to physical beginning of the vector which
/// happens to be logical end. Use blocks terminator as statement that specifies
/// destructors call site.
+/// FIXME: This mechanism for adding automatic destructors doesn't handle
+/// no-return destructors properly.
void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
LocalScope::const_iterator B, LocalScope::const_iterator E) {
- insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator());
+ BumpVectorContext &C = cfg->getBumpVectorContext();
+ CFGBlock::iterator InsertPos
+ = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
+ for (LocalScope::const_iterator I = B; I != E; ++I)
+ InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
+ Blk->getTerminator());
}
/// Visit - Walk the subtree of a statement and add extra
@@ -2861,7 +2879,22 @@ CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
if (!BindToTemporary) {
// If lifetime of temporary is not prolonged (by assigning to constant
// reference) add destructor for it.
- autoCreateBlock();
+
+ // If the destructor is marked as a no-return destructor, we need to create
+ // a new block for the destructor which does not have as a successor
+ // anything built thus far. Control won't flow out of this block.
+ const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
+ if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) {
+ Block = createBlock(/*add_successor=*/false);
+ // Wire up this block directly to the exit block if we're in the
+ // no-return case. We pruned any other successors because control flow
+ // won't actually exit this block, but we want to be able to find all of
+ // these entries in the CFG when doing analyses.
+ addSuccessor(Block, &cfg->getExit());
+ } else {
+ autoCreateBlock();
+ }
+
appendTemporaryDtor(Block, E);
B = Block;
}
diff --git a/test/SemaCXX/return-noreturn.cpp b/test/SemaCXX/return-noreturn.cpp
index 1a10c2aa16..2109efc19e 100644
--- a/test/SemaCXX/return-noreturn.cpp
+++ b/test/SemaCXX/return-noreturn.cpp
@@ -8,6 +8,8 @@ struct pr6884_abort_struct {
~pr6884_abort_struct() __attribute__((noreturn)) { pr6884_abort(); }
};
+struct other { ~other() {} };
+
// Ensure that destructors from objects are properly modeled in the CFG despite
// the presence of switches, case statements, labels, and blocks. These tests
// try to cover bugs reported in both PR6884 and PR10063.
@@ -37,9 +39,63 @@ namespace abort_struct_complex_cfgs {
switch (x) default: L1: L2: case 4: { pr6884_abort_struct(); }
}
- int h(int x) {
+ // Test that these constructs work even when extraneous blocks are created
+ // before and after the switch due to implicit destructors.
+ int g1(int x) {
+ other o;
+ switch (x) default: pr6884_abort_struct();
+ }
+ int g2(int x) {
+ other o;
+ switch (x) { default: pr6884_abort_struct(); }
+ }
+ int g2_positive(int x) {
+ other o;
+ switch (x) { default: ; }
+ } // expected-warning {{control reaches end of non-void function}}
+ int g3(int x) {
+ other o;
+ switch (x) { default: { pr6884_abort_struct(); } }
+ }
+ int g4(int x) {
+ other o;
+ switch (x) default: L1: L2: case 4: pr6884_abort_struct();
+ }
+ int g5(int x) {
+ other o;
+ switch (x) default: L1: { L2: case 4: pr6884_abort_struct(); }
+ }
+ int g6(int x) {
+ other o;
+ switch (x) default: L1: L2: case 4: { pr6884_abort_struct(); }
+ }
+
+ // Test that these constructs work even with variables carrying the no-return
+ // destructor instead of temporaries.
+ int h1(int x) {
+ other o;
+ switch (x) default: pr6884_abort_struct a;
+ }
+ int h2(int x) {
+ other o;
+ switch (x) { default: pr6884_abort_struct a; }
+ }
+ int h3(int x) {
+ other o;
switch (x) { default: { pr6884_abort_struct a; } }
}
+ int h4(int x) {
+ other o;
+ switch (x) default: L1: L2: case 4: pr6884_abort_struct a;
+ }
+ int h5(int x) {
+ other o;
+ switch (x) default: L1: { L2: case 4: pr6884_abort_struct a; }
+ }
+ int h6(int x) {
+ other o;
+ switch (x) default: L1: L2: case 4: { pr6884_abort_struct a; }
+ }
}
// PR9380
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-09-24 12:55:06 +0000