diff options
Diffstat (limited to 'src/ir/local-graph.h')
| -rw-r--r-- | src/ir/local-graph.h | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/src/ir/local-graph.h b/src/ir/local-graph.h index fd6a496c0..ae389c899 100644 --- a/src/ir/local-graph.h +++ b/src/ir/local-graph.h @@ -17,6 +17,8 @@ #ifndef wasm_ir_local_graph_h #define wasm_ir_local_graph_h +#include "wasm.h" + namespace wasm { // @@ -41,8 +43,9 @@ struct LocalGraph { typedef std::map<Expression*, Expression**> Locations; // externally useful information - GetSetses getSetses; // the sets affecting each get. a nullptr set means the initial - // value (0 for a var, the received value for a param) + GetSetses getSetses; // the sets affecting each get. a nullptr set means the + // initial value (0 for a var, the received value for a + // param) Locations locations; // where each get and set is (for easy replacing) // Optional: compute the influence graphs between sets and gets @@ -50,15 +53,18 @@ struct LocalGraph { void computeInfluences(); - std::unordered_map<GetLocal*, std::unordered_set<SetLocal*>> getInfluences; // for each get, the sets whose values are influenced by that get - std::unordered_map<SetLocal*, std::unordered_set<GetLocal*>> setInfluences; // for each set, the gets whose values are influenced by that set + // for each get, the sets whose values are influenced by that get + std::unordered_map<GetLocal*, std::unordered_set<SetLocal*>> getInfluences; + // for each set, the gets whose values are influenced by that set + std::unordered_map<SetLocal*, std::unordered_set<GetLocal*>> setInfluences; // Optional: Compute the local indexes that are SSA, in the sense of // * a single set for all the gets for that local index - // * the set dominates all the gets (logically implied by the former property) + // * the set dominates all the gets (logically implied by the former + // property) // * no other set (aside from the zero-init) - // The third property is not exactly standard SSA, but is useful since we are not in - // SSA form in our IR. To see why it matters, consider these: + // The third property is not exactly standard SSA, but is useful since we are + // not in SSA form in our IR. To see why it matters, consider these: // // x = 0 // zero init // [..] @@ -67,11 +73,11 @@ struct LocalGraph { // x = 30 // !!! // f(y) // - // The !!! line violates that property - it is another set for x, and it may interfere - // say with replacing f(y) with f(x + 20). Instead, if we know the only other possible set for x - // is the zero init, then things like the !!! line cannot exist, and it is valid to replace - // f(y) with f(x + 20). - // (This could be simpler, but in wasm the zero init always exists.) + // The !!! line violates that property - it is another set for x, and it may + // interfere say with replacing f(y) with f(x + 20). Instead, if we know the + // only other possible set for x is the zero init, then things like the !!! + // line cannot exist, and it is valid to replace f(y) with f(x + 20). (This + // could be simpler, but in wasm the zero init always exists.) void computeSSAIndexes(); @@ -84,4 +90,3 @@ private: } // namespace wasm #endif // wasm_ir_local_graph_h - |