Skip to content

Rename stack variables in CFGWalker (NFC) #6232

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
aheejin merged 2 commits into from
Jan 23, 2024
Merged

Rename stack variables in CFGWalker (NFC) #6232

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0a26d26
Rename stack variables in CFGWalker (NFC)
aheejin Jan 18, 2024
a7a841d
Revert non-NFC change
aheejin Jan 23, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
54 changes: 28 additions & 26 deletions src/cfg/cfg-traversal.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -86,12 +86,12 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
std::map<Name, std::vector<BasicBlock*>> branches;
// stack of the last blocks of if conditions + the last blocks of if true
// bodies
std::vector<BasicBlock*> ifStack;
std::vector<BasicBlock*> ifLastBlockStack;
// stack of the first blocks of loops
std::vector<BasicBlock*> loopStack;
std::vector<BasicBlock*> loopLastBlockStack;

// stack of the last blocks of try bodies
std::vector<BasicBlock*> tryStack;
std::vector<BasicBlock*> tryLastBlockStack;
// Stack of the blocks that contain a throwing instruction, and therefore they
// can reach the first blocks of catches that throwing instructions should
// unwind to at any moment. That is, the topmost item in this vector relates
Expand All @@ -100,7 +100,7 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
// of the catches, although that could be improved perhaps).
std::vector<std::vector<BasicBlock*>> throwingInstsStack;
// stack of 'Try' expressions corresponding to throwingInstsStack.
std::vector<Expression*> unwindExprStack;
std::vector<Expression*> tryStack;
// A stack for each try, where each entry is a list of blocks, one for each
// catch, used during processing. We start by assigning the start blocks to
// here, and then read those at the appropriate time; when we finish a catch
Expand Down Expand Up @@ -186,12 +186,13 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
static void doStartIfTrue(SubType* self, Expression** currp) {
auto* last = self->currBasicBlock;
self->link(last, self->startBasicBlock()); // ifTrue
self->ifStack.push_back(last); // the block before the ifTrue
self->ifLastBlockStack.push_back(last); // the block before the ifTrue
}

static void doStartIfFalse(SubType* self, Expression** currp) {
self->ifStack.push_back(self->currBasicBlock); // the ifTrue fallthrough
self->link(self->ifStack[self->ifStack.size() - 2],
self->ifLastBlockStack.push_back(
self->currBasicBlock); // the ifTrue fallthrough
self->link(self->ifLastBlockStack[self->ifLastBlockStack.size() - 2],
self->startBasicBlock()); // before if -> ifFalse
}

Expand All @@ -203,13 +204,13 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
self->link(last, self->currBasicBlock);
if ((*currp)->cast<If>()->ifFalse) {
// we just linked ifFalse, need to link ifTrue to the end
self->link(self->ifStack.back(), self->currBasicBlock);
self->ifStack.pop_back();
self->link(self->ifLastBlockStack.back(), self->currBasicBlock);
self->ifLastBlockStack.pop_back();
} else {
// no ifFalse, so add a fallthrough for if the if is not taken
self->link(self->ifStack.back(), self->currBasicBlock);
self->link(self->ifLastBlockStack.back(), self->currBasicBlock);
}
self->ifStack.pop_back();
self->ifLastBlockStack.pop_back();
}

static void doStartLoop(SubType* self, Expression** currp) {
Expand All @@ -218,7 +219,7 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
// a loop with no backedges would still be counted here, but oh well
self->loopTops.push_back(self->currBasicBlock);
self->link(last, self->currBasicBlock);
self->loopStack.push_back(self->currBasicBlock);
self->loopLastBlockStack.push_back(self->currBasicBlock);
}

static void doEndLoop(SubType* self, Expression** currp) {
Expand All @@ -227,14 +228,14 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
auto* curr = (*currp)->cast<Loop>();
// branches to the top of the loop
if (curr->name.is()) {
auto* loopStart = self->loopStack.back();
auto* loopStart = self->loopLastBlockStack.back();
auto& origins = self->branches[curr->name];
for (auto* origin : origins) {
self->link(origin, loopStart);
}
self->branches.erase(curr->name);
}
self->loopStack.pop_back();
self->loopLastBlockStack.pop_back();
}

static void doEndBranch(SubType* self, Expression** currp) {
Expand Down Expand Up @@ -278,9 +279,9 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
// catch $e3
// ...
// end
assert(self->unwindExprStack.size() == self->throwingInstsStack.size());
assert(self->tryStack.size() == self->throwingInstsStack.size());
for (int i = self->throwingInstsStack.size() - 1; i >= 0;) {
auto* tryy = self->unwindExprStack[i]->template cast<Try>();
auto* tryy = self->tryStack[i]->template cast<Try>();
if (tryy->isDelegate()) {
// If this delegates to the caller, there is no possibility that this
// instruction can throw to outer catches.
Expand All @@ -291,7 +292,7 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
// and the target try.
[[maybe_unused]] bool found = false;
for (int j = i - 1; j >= 0; j--) {
if (self->unwindExprStack[j]->template cast<Try>()->name ==
if (self->tryStack[j]->template cast<Try>()->name ==
tryy->delegateTarget) {
i = j;
found = true;
Expand Down Expand Up @@ -348,11 +349,12 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
static void doStartTry(SubType* self, Expression** currp) {
auto* curr = (*currp)->cast<Try>();
self->throwingInstsStack.emplace_back();
self->unwindExprStack.push_back(curr);
self->tryStack.push_back(curr);
}

static void doStartCatches(SubType* self, Expression** currp) {
self->tryStack.push_back(self->currBasicBlock); // last block of try body
self->tryLastBlockStack.push_back(
self->currBasicBlock); // last block of try body

// Now that we are starting the catches, create the basic blocks that they
// begin with.
Expand All @@ -374,7 +376,7 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
}

self->throwingInstsStack.pop_back();
self->unwindExprStack.pop_back();
self->tryStack.pop_back();
self->catchIndexStack.push_back(0);
}

Expand All @@ -398,8 +400,8 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
self->link(last, self->currBasicBlock);
}
// try body's last block -> continuation block
self->link(self->tryStack.back(), self->currBasicBlock);
self->tryStack.pop_back();
self->link(self->tryLastBlockStack.back(), self->currBasicBlock);
self->tryLastBlockStack.pop_back();
self->processCatchStack.pop_back();
self->catchIndexStack.pop_back();
}
Expand Down Expand Up @@ -522,11 +524,11 @@ struct CFGWalker : public PostWalker<SubType, VisitorType> {
}

assert(branches.size() == 0);
assert(ifStack.size() == 0);
assert(loopStack.size() == 0);
assert(tryStack.size() == 0);
assert(ifLastBlockStack.size() == 0);
assert(loopLastBlockStack.size() == 0);
assert(tryLastBlockStack.size() == 0);
assert(throwingInstsStack.size() == 0);
assert(unwindExprStack.size() == 0);
assert(tryStack.size() == 0);
assert(processCatchStack.size() == 0);
}

Expand Down