/**
* Link primary body blocks to exception handler blocks as follows:
* 1. For each block in the body, traverse from the innermost to
* outermost exception handler that includes the block. For
* catch handlers, add an edge to each handler entry point. For
* fault handlers, add an edge to the fault handler and stop.
* 2. For each fault handler block ending in Unwind, find the EH
* entry for the funclet, then traverse outwards starting from the
* next outermost. Add any catch edges found, and stop at the first
* enclosing fault funclet, as in step 1.
* The resulting linkage reflects exception control-flow; fault funclets
* unconditionally handle any exception in their protected region, so they
* "dominate" outer-more handlers.
*/
void GraphBuilder::linkExBlocks() {
// For every block, add edges to reachable fault and catch handlers.
for (LinearBlocks i = linearBlocks(m_graph); !i.empty(); ) {
Block* b = i.popFront();
assert(m_func->findEH(offset(b->start)) == m_func->findEH(offset(b->last)));
Offset off = offset(b->start);
const EHEnt* eh = m_func->findEH(off);
if (eh != nullptr) {
assert(eh->m_base <= off && off < eh->m_past);
// the innermost exception handler is reachable from b
b->exn = at(eh->m_handler);
}
}
}
/**
* Link primary body blocks to exception handler blocks as follows:
* 1. For each block in the body, traverse from the innermost to
* outermost exception handler that includes the block. For
* catch handlers, add an edge to each handler entry point. For
* fault handlers, add an edge to the fault handler and stop.
* 2. For each fault handler block ending in Unwind, find the EH
* entry for the funclet, then traverse outwards starting from the
* next outermost. Add any catch edges found, and stop at the first
* enclosing fault funclet, as in step 1.
* The resulting linkage reflects exception control-flow; fault funclets
* unconditionally handle any exception in their protected region, so they
* "dominate" outer-more handlers.
*/
void GraphBuilder::linkExBlocks() {
const Func::EHEntVec& ehtab = m_func->ehtab();
// For every block, add edges to reachable fault and catch handlers.
for (LinearBlocks i = linearBlocks(m_graph); !i.empty(); ) {
Block* b = i.popFront();
assert(m_func->findEH(offset(b->start)) == m_func->findEH(offset(b->last)));
Offset off = offset(b->start);
int exn_index = 0;
for (const EHEnt* eh = m_func->findEH(off); eh != 0; ) {
assert(eh->m_base <= off && off < eh->m_past);
if (eh->m_type == EHEnt::Type::Catch) {
// each catch block is reachable from b
for (Range<EHEnt::CatchVec> j(eh->m_catches); !j.empty(); ) {
exns(b)[exn_index++] = at(j.popFront().second);
}
eh = nextOuter(ehtab, eh);
} else {
// this is the innermost fault funclet reachable from b.
exns(b)[exn_index++] = at(eh->m_fault);
break;
}
}
if (Op(*b->last) == OpUnwind) {
// We're in a fault funclet. Find which one, then add edges
// to reachable catches and the enclosing fault funclet, if any.
const EHEnt* eh = findFunclet(ehtab, offset(b->last));
eh = nextOuter(ehtab, eh);
while (eh) {
if (eh->m_type == EHEnt::Type::Catch) {
// each catch target for eh is reachable from b
for (Range<EHEnt::CatchVec> j(eh->m_catches); !j.empty(); ) {
exns(b)[exn_index++] = at(j.popFront().second);
}
eh = nextOuter(ehtab, eh);
} else {
// eh is the innermost fault funclet reachable from b.
exns(b)[exn_index++] = at(eh->m_fault);
break;
}
}
}
}
}
bool ProfData::anyBlockEndsAt(const Func* func, Offset offset) {
auto const mapIt = m_blockEndOffsets.find(func->getFuncId());
if (mapIt != end(m_blockEndOffsets)) {
return mapIt->second.count(offset);
}
using namespace Verifier;
Arena arena;
GraphBuilder builder{arena, func};
auto cfg = builder.build();
auto& offsets = m_blockEndOffsets[func->getFuncId()];
for (LinearBlocks blocks = linearBlocks(cfg); !blocks.empty(); ) {
auto last = blocks.popFront()->last - func->unit()->entry();
offsets.insert(last);
}
return offsets.count(offset);
}
bool Func::anyBlockEndsAt(Offset off) const {
assert(JIT::Translator::WriteLease().amOwner());
// The empty() check relies on a Func's bytecode always being nonempty
assert(base() != past());
if (m_shared->m_blockEnds.empty()) {
using namespace Verifier;
Arena arena;
GraphBuilder builder{arena, this};
Graph* cfg = builder.build();
for (LinearBlocks blocks = linearBlocks(cfg); !blocks.empty(); ) {
auto last = blocks.popFront()->last - m_unit->entry();
m_shared->m_blockEnds.insert(last);
}
assert(!m_shared->m_blockEnds.empty());
}
return m_shared->m_blockEnds.count(off) != 0;
}
void printGml(const Unit* unit) {
string filename = unit->md5().toString() + ".gml";
FILE* file = fopen(filename.c_str(), "w");
if (!file) {
std::cerr << "Couldn't open GML output file " << filename << std::endl;
return;
}
int nextid = 1;
fprintf(file, "graph [\n"
" hierarchic 1\n"
" directed 1\n");
for (AllFuncs i(unit); !i.empty(); ) {
const Func* func = i.popFront();
Arena scratch;
GraphBuilder builder(scratch, func);
const Graph* g = builder.build();
int gid = nextid++;
fprintf(file, "node [ isGroup 1 id %d ]\n", gid);
// nodes
for (LinearBlocks j = linearBlocks(g); !j.empty();) {
const Block* b = j.popFront();
std::stringstream strbuf;
unit->prettyPrint(strbuf,
Unit::PrintOpts().range(unit->offsetOf(b->start),
unit->offsetOf(b->end)));
std::string code = strbuf.str();
for (int i = 0, n = code.size(); i < n; ++i) {
if (code[i] == '"') code[i] = '\'';
}
fprintf(file, " node [ id %d gid %d\n"
" graphics [ type \"roundrectangle\" ]"
" LabelGraphics ["
" anchor \"e\""
" alignment \"left\""
" fontName \"Consolas\"\n"
" text \"%s\"\n"
" ]\n"
" ]\n",
nextid + b->id, gid, code.c_str());
}
// edges
for (LinearBlocks j = linearBlocks(g); !j.empty();) {
const Block* b = j.popFront();
for (BlockPtrRange k = succBlocks(b); !k.empty();) {
const Block* s = k.popFront();
fprintf(file, " edge [ source %d target %d ]\n",
nextid + b->id, nextid + s->id);
}
for (BlockPtrRange k = exnBlocks(g, b); !k.empty();) {
const Block* s = k.popFront();
fprintf(file, " edge [ source %d target %d"
" graphics [ style \"dotted\" ]"
" ]\n",
nextid + b->id, nextid + s->id);
}
}
nextid += g->block_count + 1;
}
fprintf(file, "]\n");
fclose(file);
}