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ICU-22934 Limit the number of resursive call

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To avoid stack overflow while building RBBI
This commit is contained in:
Frank Tang 2024-10-01 13:58:01 -07:00 • committed by Frank Yung-Fong Tang
parent 8437d1d86b
commit 5b45e5c64b
3 changed files with 44 additions and 18 deletions
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56
icu4c/source/common/rbbinode.cpp
View file

@ -193,13 +193,23 @@ void RBBINode::NRDeleteNode(RBBINode *node) {
// references in preparation for generating the DFA tables.
//
//-------------------------------------------------------------------------
RBBINode *RBBINode::cloneTree() {
constexpr int kRecursiveDepthLimit = 3500;
RBBINode *RBBINode::cloneTree(UErrorCode &status, int depth) {
if (U_FAILURE(status)) {
return nullptr;
}
// If the depth of the stack is too deep, we return U_INPUT_TOO_LONG_ERROR
// to avoid stack overflow crash.
if (depth > kRecursiveDepthLimit) {
status = U_INPUT_TOO_LONG_ERROR;
return nullptr;
}
RBBINode *n;
if (fType == RBBINode::varRef) {
// If the current node is a variable reference, skip over it
// and clone the definition of the variable instead.
n = fLeftChild->cloneTree();
n = fLeftChild->cloneTree(status, depth+1);
} else if (fType == RBBINode::uset) {
n = this;
} else {
@ -207,12 +217,16 @@ RBBINode *RBBINode::cloneTree() {
// Check for null pointer.
if (n != nullptr) {
if (fLeftChild != nullptr) {
n->fLeftChild = fLeftChild->cloneTree();
n->fLeftChild->fParent = n;
n->fLeftChild = fLeftChild->cloneTree(status, depth+1);
if (U_SUCCESS(status)) {
n->fLeftChild->fParent = n;
}
}
if (fRightChild != nullptr) {
n->fRightChild = fRightChild->cloneTree();
n->fRightChild->fParent = n;
n->fRightChild = fRightChild->cloneTree(status, depth+1);
if (U_SUCCESS(status)) {
n->fRightChild->fParent = n;
}
}
}
}
@ -239,7 +253,6 @@ RBBINode *RBBINode::cloneTree() {
// nested references are handled by cloneTree(), not here.
//
//-------------------------------------------------------------------------
constexpr int kRecursiveDepthLimit = 3500;
RBBINode *RBBINode::flattenVariables(UErrorCode& status, int depth) {
if (U_FAILURE(status)) {
return this;
@ -251,7 +264,7 @@ RBBINode *RBBINode::flattenVariables(UErrorCode& status, int depth) {
return this;
}
if (fType == varRef) {
RBBINode *retNode = fLeftChild->cloneTree();
RBBINode *retNode = fLeftChild->cloneTree(status, depth+1);
if (retNode != nullptr) {
retNode->fRuleRoot = this->fRuleRoot;
retNode->fChainIn = this->fChainIn;
@ -280,7 +293,16 @@ RBBINode *RBBINode::flattenVariables(UErrorCode& status, int depth) {
// the left child of the uset node.
//
//-------------------------------------------------------------------------
void RBBINode::flattenSets() {
void RBBINode::flattenSets(UErrorCode &status, int depth) {
if (U_FAILURE(status)) {
return;
}
// If the depth of the stack is too deep, we return U_INPUT_TOO_LONG_ERROR
// to avoid stack overflow crash.
if (depth > kRecursiveDepthLimit) {
status = U_INPUT_TOO_LONG_ERROR;
return;
}
U_ASSERT(fType != setRef);
if (fLeftChild != nullptr) {
@ -288,11 +310,13 @@ void RBBINode::flattenSets() {
RBBINode *setRefNode = fLeftChild;
RBBINode *usetNode = setRefNode->fLeftChild;
RBBINode *replTree = usetNode->fLeftChild;
fLeftChild = replTree->cloneTree();
fLeftChild->fParent = this;
fLeftChild = replTree->cloneTree(status, depth+1);
if (U_FAILURE(status)) {
fLeftChild->fParent = this;
}
delete setRefNode;
} else {
fLeftChild->flattenSets();
fLeftChild->flattenSets(status, depth+1);
}
}
@ -301,11 +325,13 @@ void RBBINode::flattenSets() {
RBBINode *setRefNode = fRightChild;
RBBINode *usetNode = setRefNode->fLeftChild;
RBBINode *replTree = usetNode->fLeftChild;
fRightChild = replTree->cloneTree();
fRightChild->fParent = this;
fRightChild = replTree->cloneTree(status, depth+1);
if (U_FAILURE(status)) {
fRightChild->fParent = this;
}
delete setRefNode;
} else {
fRightChild->flattenSets();
fRightChild->flattenSets(status, depth+1);
}
}
}

4
icu4c/source/common/rbbinode.h
View file

@ -96,9 +96,9 @@ class RBBINode : public UMemory {
~RBBINode();
static void NRDeleteNode(RBBINode *node);
RBBINode *cloneTree();
RBBINode *cloneTree(UErrorCode &status, int depth=0);
RBBINode *flattenVariables(UErrorCode &status, int depth=0);
void flattenSets();
void flattenSets(UErrorCode &status, int depth=0);
void findNodes(UVector *dest, RBBINode::NodeType kind, UErrorCode &status);
#ifdef RBBI_DEBUG

2
icu4c/source/common/rbbitblb.cpp
View file

@ -142,7 +142,7 @@ void RBBITableBuilder::buildForwardTable() {
// Replace all references to UnicodeSets with the tree for the equivalent
// expression.
//
fTree->flattenSets();
fTree->flattenSets(*fStatus, 0);
#ifdef RBBI_DEBUG
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "stree")) {
RBBIDebugPuts("\nParse tree after flattening Unicode Set references.");