diff options
Diffstat (limited to 'archive/1.vm/041jump_target.cc')
| -rw-r--r-- | archive/1.vm/041jump_target.cc | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/archive/1.vm/041jump_target.cc b/archive/1.vm/041jump_target.cc new file mode 100644 index 00000000..ec7adede --- /dev/null +++ b/archive/1.vm/041jump_target.cc @@ -0,0 +1,220 @@ +//: Support jumps to a specific label (the 'jump target') in the same recipe. +//: Jump targets must be unique and unambiguous within any recipe. +//: +//: The 'break' and 'loop' pseudo instructions can also take jump targets. +//: Which instruction you use is just documentation about intent; use 'break' +//: to indicate you're exiting one or more loop nests, and 'loop' to indicate +//: you're skipping to the next iteration of some containing loop nest. + +//: Since they have to be unique in a recipe, not all labels can be jump +//: targets. +bool is_jump_target(const string& label) { + if (label == "{" || label == "}") return false; + // End is_jump_target Special-cases + return is_label_word(label); +} + +void test_jump_to_label() { + run( + "def main [\n" + " jump +target:label\n" + " 1:num <- copy 0\n" + " +target\n" + "]\n" + ); + CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 1"); +} + +:(before "End Mu Types Initialization") +put(Type_ordinal, "label", 0); + +:(before "End Instruction Modifying Transforms") +Transform.push_back(transform_labels); // idempotent + +:(code) +void transform_labels(const recipe_ordinal r) { + map<string, int> offset; + for (int i = 0; i < SIZE(get(Recipe, r).steps); ++i) { + const instruction& inst = get(Recipe, r).steps.at(i); + if (!inst.is_label) continue; + if (is_jump_target(inst.label)) { + if (!contains_key(offset, inst.label)) { + put(offset, inst.label, i); + } + else { + raise << maybe(get(Recipe, r).name) << "duplicate label '" << inst.label << "'" << end(); + // have all jumps skip some random but noticeable and deterministic amount of code + put(offset, inst.label, 9999); + } + } + } + for (int i = 0; i < SIZE(get(Recipe, r).steps); ++i) { + instruction& inst = get(Recipe, r).steps.at(i); + if (inst.name == "jump") { + if (inst.ingredients.empty()) { + raise << maybe(get(Recipe, r).name) << "'" << to_original_string(inst) << "' expects an ingredient but got 0\n" << end(); + return; + } + replace_offset(inst.ingredients.at(0), offset, i, r); + } + if (inst.name == "jump-if" || inst.name == "jump-unless") { + if (SIZE(inst.ingredients) < 2) { + raise << maybe(get(Recipe, r).name) << "'" << to_original_string(inst) << "' expects 2 ingredients but got " << SIZE(inst.ingredients) << '\n' << end(); + return; + } + replace_offset(inst.ingredients.at(1), offset, i, r); + } + if ((inst.name == "loop" || inst.name == "break") + && SIZE(inst.ingredients) >= 1) { + replace_offset(inst.ingredients.at(0), offset, i, r); + } + if ((inst.name == "loop-if" || inst.name == "loop-unless" + || inst.name == "break-if" || inst.name == "break-unless") + && SIZE(inst.ingredients) >= 2) { + replace_offset(inst.ingredients.at(1), offset, i, r); + } + } +} + +void replace_offset(reagent& x, /*const*/ map<string, int>& offset, const int current_offset, const recipe_ordinal r) { + if (!is_literal(x)) { + raise << maybe(get(Recipe, r).name) << "jump target must be offset or label but is '" << x.original_string << "'\n" << end(); + x.set_value(0); // no jump by default + return; + } + if (x.initialized) return; + if (is_integer(x.name)) return; // non-labels will be handled like other number operands + if (!is_jump_target(x.name)) { + raise << maybe(get(Recipe, r).name) << "can't jump to label '" << x.name << "'\n" << end(); + x.set_value(0); // no jump by default + return; + } + if (!contains_key(offset, x.name)) { + raise << maybe(get(Recipe, r).name) << "can't find label '" << x.name << "'\n" << end(); + x.set_value(0); // no jump by default + return; + } + x.set_value(get(offset, x.name) - current_offset); +} + +void test_break_to_label() { + run( + "def main [\n" + " {\n" + " {\n" + " break +target:label\n" + " 1:num <- copy 0\n" + " }\n" + " }\n" + " +target\n" + "]\n" + ); + CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 1"); +} + +void test_jump_if_to_label() { + run( + "def main [\n" + " {\n" + " {\n" + " jump-if 1, +target:label\n" + " 1:num <- copy 0\n" + " }\n" + " }\n" + " +target\n" + "]\n" + ); + CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 1"); +} + +void test_loop_unless_to_label() { + run( + "def main [\n" + " {\n" + " {\n" + " loop-unless 0, +target:label\n" // loop/break with a label don't care about braces + " 1:num <- copy 0\n" + " }\n" + " }\n" + " +target\n" + "]\n" + ); + CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 1"); +} + +void test_jump_runs_code_after_label() { + run( + "def main [\n" + // first a few lines of padding to exercise the offset computation + " 1:num <- copy 0\n" + " 2:num <- copy 0\n" + " 3:num <- copy 0\n" + " jump +target:label\n" + " 4:num <- copy 0\n" + " +target\n" + " 5:num <- copy 0\n" + "]\n" + ); + CHECK_TRACE_CONTENTS( + "mem: storing 0 in location 5\n" + ); + CHECK_TRACE_DOESNT_CONTAIN("mem: storing 0 in location 4"); +} + +void test_jump_fails_without_target() { + Hide_errors = true; + run( + "def main [\n" + " jump\n" + "]\n" + ); + CHECK_TRACE_CONTENTS( + "error: main: 'jump' expects an ingredient but got 0\n" + ); +} + +void test_jump_fails_without_target_2() { + Hide_errors = true; + run( + "def main [\n" + " jump-if true\n" + "]\n" + ); + CHECK_TRACE_CONTENTS( + "error: main: 'jump-if true' expects 2 ingredients but got 1\n" + ); +} + +void test_recipe_fails_on_duplicate_jump_target() { + Hide_errors = true; + run( + "def main [\n" + " +label\n" + " 1:num <- copy 0\n" + " +label\n" + " 2:num <- copy 0\n" + "]\n" + ); + CHECK_TRACE_CONTENTS( + "error: main: duplicate label '+label'\n" + ); +} + +void test_jump_ignores_nontarget_label() { + Hide_errors = true; + run( + "def main [\n" + // first a few lines of padding to exercise the offset computation + " 1:num <- copy 0\n" + " 2:num <- copy 0\n" + " 3:num <- copy 0\n" + " jump $target:label\n" + " 4:num <- copy 0\n" + " $target\n" + " 5:num <- copy 0\n" + "]\n" + ); + CHECK_TRACE_CONTENTS( + "error: main: can't jump to label '$target'\n" + ); +} |