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-rw-r--r--src/wasm/wasm-debug.cpp122
1 files changed, 90 insertions, 32 deletions
diff --git a/src/wasm/wasm-debug.cpp b/src/wasm/wasm-debug.cpp
index a244e550d..23bc83374 100644
--- a/src/wasm/wasm-debug.cpp
+++ b/src/wasm/wasm-debug.cpp
@@ -335,7 +335,7 @@ struct AddrExprMap {
// Construct the map from the binaryLocations loaded from the wasm.
AddrExprMap(const Module& wasm) {
for (auto& func : wasm.functions) {
- for (auto pair : func->binaryLocations) {
+ for (auto pair : func->expressionLocations) {
assert(map.count(pair.second) == 0);
map[pair.second] = pair.first;
}
@@ -343,8 +343,8 @@ struct AddrExprMap {
}
// Construct the map from new binaryLocations just written
- AddrExprMap(const BinaryLocationsMap& newLocations) {
- for (auto pair : newLocations) {
+ AddrExprMap(const BinaryLocations& newLocations) {
+ for (auto pair : newLocations.expressions) {
assert(map.count(pair.second) == 0);
map[pair.second] = pair.first;
}
@@ -366,12 +366,51 @@ struct AddrExprMap {
}
};
+// Represents a mapping of addresses to expressions.
+struct FuncAddrMap {
+ std::unordered_map<uint32_t, Function*> map;
+
+ // Construct the map from the binaryLocations loaded from the wasm.
+ FuncAddrMap(const Module& wasm) {
+ for (auto& func : wasm.functions) {
+ map[func->funcLocation.start] = func.get();
+ map[func->funcLocation.end] = func.get();
+ }
+ }
+
+ Function* get(uint32_t addr) const {
+ auto iter = map.find(addr);
+ if (iter != map.end()) {
+ return iter->second;
+ }
+ return nullptr;
+ }
+
+ void dump() const {
+ std::cout << " (size: " << map.size() << ")\n";
+ for (auto pair : map) {
+ std::cout << " " << pair.first << " => " << pair.second->name << '\n';
+ }
+ }
+};
+
+// Track locations from the original binary and the new one we wrote, so that
+// we can update debug positions.
+// We track expressions and functions separately, instead of having a single
+// big map of (oldAddr) => (newAddr) because of the potentially ambiguous case
+// of the final expression in a function: it's end might be identical in offset
+// to the end of the function. So we have two different things that map to the
+// same offset. However, if the context is "the end of the function" then the
+// updated address is the new end of the function, even if the function ends
+// with a different instruction now, as the old last instruction might have
+// moved or been optimized out.
struct LocationUpdater {
Module& wasm;
- const BinaryLocationsMap& newLocations;
+ const BinaryLocations& newLocations;
- AddrExprMap oldAddrMap;
- AddrExprMap newAddrMap;
+ AddrExprMap oldExprAddrMap;
+ AddrExprMap newExprAddrMap;
+ FuncAddrMap oldFuncAddrMap;
// TODO: for memory efficiency, we may want to do this in a streaming manner,
// binary to binary, without YAML IR.
@@ -380,17 +419,17 @@ struct LocationUpdater {
// we may need to track their spans too
// https://github.com/WebAssembly/debugging/issues/9#issuecomment-567720872
- LocationUpdater(Module& wasm, const BinaryLocationsMap& newLocations)
- : wasm(wasm), newLocations(newLocations), oldAddrMap(wasm),
- newAddrMap(newLocations) {}
-
- // Updates an address. If there was never an instruction at that address,
- // or if there was but if that instruction no longer exists, return 0.
- // Otherwise, return the new updated location.
- uint32_t getNewAddr(uint32_t oldAddr) const {
- if (auto* expr = oldAddrMap.get(oldAddr)) {
- auto iter = newLocations.find(expr);
- if (iter != newLocations.end()) {
+ LocationUpdater(Module& wasm, const BinaryLocations& newLocations)
+ : wasm(wasm), newLocations(newLocations), oldExprAddrMap(wasm),
+ newExprAddrMap(newLocations), oldFuncAddrMap(wasm) {}
+
+ // Updates an expression's address. If there was never an instruction at that
+ // address, or if there was but if that instruction no longer exists, return
+ // 0. Otherwise, return the new updated location.
+ uint32_t getNewExprAddr(uint32_t oldAddr) const {
+ if (auto* expr = oldExprAddrMap.get(oldAddr)) {
+ auto iter = newLocations.expressions.find(expr);
+ if (iter != newLocations.expressions.end()) {
uint32_t newAddr = iter->second;
return newAddr;
}
@@ -398,7 +437,22 @@ struct LocationUpdater {
return 0;
}
- bool hasOldAddr(uint32_t oldAddr) const { return oldAddrMap.get(oldAddr); }
+ uint32_t getNewFuncAddr(uint32_t oldAddr) const {
+ if (auto* func = oldFuncAddrMap.get(oldAddr)) {
+ // The function might have been optimized away, check.
+ auto iter = newLocations.functions.find(func);
+ if (iter != newLocations.functions.end()) {
+ auto oldSpan = func->funcLocation;
+ auto newSpan = iter->second;
+ if (oldAddr == oldSpan.start) {
+ return newSpan.start;
+ } else if (oldAddr == oldSpan.end) {
+ return newSpan.end;
+ }
+ }
+ }
+ return 0;
+ }
};
static void updateDebugLines(llvm::DWARFYAML::Data& data,
@@ -428,7 +482,7 @@ static void updateDebugLines(llvm::DWARFYAML::Data& data,
}
// An expression may not exist for this line table item, if we optimized
// it away.
- if (auto newAddr = locationUpdater.getNewAddr(state.addr)) {
+ if (auto newAddr = locationUpdater.getNewExprAddr(state.addr)) {
newAddrs.push_back(newAddr);
newAddrInfo.emplace(newAddr, state);
auto& updatedState = newAddrInfo.at(newAddr);
@@ -491,6 +545,7 @@ static void updateCompileUnits(const BinaryenDWARFInfo& info,
yamlUnit.Entries,
[&](const llvm::DWARFDebugInfoEntry& DIE,
llvm::DWARFYAML::Entry& yamlEntry) {
+ auto tag = DIE.getTag();
// Process the entries in each relevant DIE, looking for attributes to
// change.
auto abbrevDecl = DIE.getAbbreviationDeclarationPtr();
@@ -502,18 +557,21 @@ static void updateCompileUnits(const BinaryenDWARFInfo& info,
attrSpec,
llvm::DWARFYAML::FormValue& yamlValue) {
if (attrSpec.Attr == llvm::dwarf::DW_AT_low_pc) {
- // If the old address did not refer to an instruction, then
- // this is not something we understand and can update.
- if (locationUpdater.hasOldAddr(yamlValue.Value)) {
- // The addresses of compile units and functions are not
- // instructions.
- assert(DIE.getTag() != llvm::dwarf::DW_TAG_compile_unit &&
- DIE.getTag() != llvm::dwarf::DW_TAG_subprogram);
- // Note that the new value may be 0, which is the correct
- // way to indicate that this is no longer a valid wasm
- // value, the same as wasm-ld would do.
+ if (tag == llvm::dwarf::DW_TAG_GNU_call_site ||
+ tag == llvm::dwarf::DW_TAG_inlined_subroutine ||
+ tag == llvm::dwarf::DW_TAG_lexical_block ||
+ tag == llvm::dwarf::DW_TAG_label) {
+ // low_pc in certain tags represent expressions.
+ yamlValue.Value =
+ locationUpdater.getNewExprAddr(yamlValue.Value);
+ } else if (tag == llvm::dwarf::DW_TAG_compile_unit ||
+ tag == llvm::dwarf::DW_TAG_subprogram) {
+ // low_pc in certain tags represent function.
yamlValue.Value =
- locationUpdater.getNewAddr(yamlValue.Value);
+ locationUpdater.getNewFuncAddr(yamlValue.Value);
+ } else {
+ Fatal() << "unknown tag with low_pc "
+ << llvm::dwarf::TagString(tag).str();
}
}
});
@@ -522,7 +580,7 @@ static void updateCompileUnits(const BinaryenDWARFInfo& info,
});
}
-void writeDWARFSections(Module& wasm, const BinaryLocationsMap& newLocations) {
+void writeDWARFSections(Module& wasm, const BinaryLocations& newLocations) {
BinaryenDWARFInfo info(wasm);
// Convert to Data representation, which YAML can use to write.
@@ -563,7 +621,7 @@ void dumpDWARF(const Module& wasm) {
std::cerr << "warning: no DWARF dumping support present\n";
}
-void writeDWARFSections(Module& wasm, const BinaryLocationsMap& newLocations) {
+void writeDWARFSections(Module& wasm, const BinaryLocations& newLocations) {
std::cerr << "warning: no DWARF updating support present\n";
}
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