about summary refs log tree commit diff stats
path: root/010vm.cc
Commit message (Collapse)AuthorAgeFilesLines
* 3809Kartik K. Agaram2017-04-041-1/+2
|
* 3744Kartik K. Agaram2017-02-071-1/+0
| | | | | | Undo 3743. Really any time we create new instructions from whole cloth during rewriting or transform, the whole notion of 'original name' goes out the window. Pointless trying to fight that fact of life.
* 3743Kartik K. Agaram2017-02-071-0/+1
| | | | | | | | One way to ensure we always set old_name is to create a method to initialize names as opposed to just assigning them. Still not ideal because we still assign directly most of the time, so it's easy to forget.
* 3742 - move instruction.old_name to a later layerKartik K. Agaram2017-02-061-2/+0
| | | | | | The drawback of this is that we forget to initialize old_name when we create instructions out of whole cloth in a few places. But this problem already existed..
* 3741Kartik K. Agaram2017-02-061-12/+20
| | | | Eliminate a long-standing under-abstraction.
* 3740Kartik K. Agaram2017-02-061-1/+2
|
* 3739Kartik K. Agaram2017-02-061-1/+11
|
* 3666Kartik K. Agaram2016-11-111-0/+2
| | | | Fix a memory leak.
* 3665Kartik K. Agaram2016-11-111-22/+22
|
* 3663 - fix a refcounting bug: '(type)' != 'type'Kartik K. Agaram2016-11-101-18/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was a large commit, and most of it is a follow-up to commit 3309, undoing what is probably the final ill-considered optimization I added to s-expressions in Mu: I was always representing (a b c) as (a b . c), etc. That is now gone. Why did I need to take it out? The key problem was the error silently ignored in layer 30. That was causing size_of("(type)") to silently return garbage rather than loudly complain (assuming 'type' was a simple type). But to take it out I had to modify types_strictly_match (layer 21) to actually strictly match and not just do a prefix match. In the process of removing the prefix match, I had to make extracting recipe types from recipe headers more robust. So far it only matched the first element of each ingredient's type; these matched: (recipe address:number -> address:number) (recipe address -> address) I didn't notice because the dotted notation optimization was actually representing this as: (recipe address:number -> address number) --- One final little thing in this commit: I added an alias for 'assert' called 'assert_for_now', to indicate that I'm not sure something's really an invariant, that it might be triggered by (invalid) user programs, and so require more thought on error handling down the road. But this may well be an ill-posed distinction. It may be overwhelmingly uneconomic to continually distinguish between model invariants and error states for input. I'm starting to grow sympathetic to Google Analytics's recent approach of just banning assertions altogether. We'll see..
* 3561Kartik K. Agaram2016-10-221-5/+5
|
* 3560Kartik K. Agaram2016-10-221-1/+1
|
* 3549Kartik K. Agaram2016-10-221-1/+1
| | | | | | | | | | | | | | | | | | More consistent definitions for jump targets and waypoints. 1. A label is a word starting with something other than a letter or digit or '$'. 2. A waypoint is a label that starts with '<' and ends with '>'. It has no restrictions. A recipe can define any number of waypoints, and recipes can have duplicate waypoints. 3. The special labels '{' and '}' can also be duplicated any number of times in a recipe. The only constraint on them is that they have to balance in any recipe. Every '{' must be followed by a matching '}'. 4. All other labels are 'jump targets'. You can't have duplicate jump targets in a recipe; that would make jumps ambiguous.
* 3522Kartik K. Agaram2016-10-191-20/+20
|
* 3408Kartik K. Agaram2016-09-221-0/+4
|
* 3313Kartik K. Agaram2016-09-101-0/+83
| | | | | | | Allow type-trees to be ordered in some consistent fashion. This could be quite inefficient since we often end up comparing the four sub-trees of the two arguments in 4 different ways. So far it isn't much of a time sink.
* 3310Kartik K. Agaram2016-09-101-1/+2
| | | | | Turns out the slowdown reported in 3309 was almost entirely due to commit 3305: supporting extremely small floating point numbers.
* 3309Kartik K. Agaram2016-09-091-73/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rip out everything to fix one failing unit test (commit 3290; type abbreviations). This commit does several things at once that I couldn't come up with a clean way to unpack: A. It moves to a new representation for type trees without changing the actual definition of the `type_tree` struct. B. It adds unit tests for our type metadata precomputation, so that errors there show up early and in a simpler setting rather than dying when we try to load Mu code. C. It fixes a bug, guarding against infinite loops when precomputing metadata for recursive shape-shifting containers. To do this it uses a dumb way of comparing type_trees, comparing their string representations instead. That is likely incredibly inefficient. Perhaps due to C, this commit has made Mu incredibly slow. Running all tests for the core and the edit/ app now takes 6.5 minutes rather than 3.5 minutes. == more notes and details I've been struggling for the past week now to back out of a bad design decision, a premature optimization from the early days: storing atoms directly in the 'value' slot of a cons cell rather than creating a special 'atom' cons cell and storing it on the 'left' slot. In other words, if a cons cell looks like this: o / | \ left val right ..then the type_tree (a b c) used to look like this (before this commit): o | \ a o | \ b o | \ c null ..rather than like this 'classic' approach to s-expressions which never mixes val and right (which is what we now have): o / \ o o | / \ a o o | / \ b o null | c The old approach made several operations more complicated, most recently the act of replacing a (possibly atom/leaf) sub-tree with another. That was the final straw that got me to realize the contortions I was going through to save a few type_tree nodes (cons cells). Switching to the new approach was hard partly because I've been using the old approach for so long and type_tree manipulations had pervaded everything. Another issue I ran into was the realization that my layers were not cleanly separated. Key parts of early layers (precomputing type metadata) existed purely for far later ones (shape-shifting types). Layers I got repeatedly stuck at: 1. the transform for precomputing type sizes (layer 30) 2. type-checks on merge instructions (layer 31) 3. the transform for precomputing address offsets in types (layer 36) 4. replace operations in supporting shape-shifting recipes (layer 55) After much thrashing I finally noticed that it wasn't the entirety of these layers that was giving me trouble, but just the type metadata precomputation, which had bugs that weren't manifesting until 30 layers later. Or, worse, when loading .mu files before any tests had had a chance to run. A common failure mode was running into types at run time that I hadn't precomputed metadata for at transform time. Digging into these bugs got me to realize that what I had before wasn't really very good, but a half-assed heuristic approach that did a whole lot of extra work precomputing metadata for utterly meaningless types like `((address number) 3)` which just happened to be part of a larger type like `(array (address number) 3)`. So, I redid it all. I switched the representation of types (because the old representation made unit tests difficult to retrofit) and added unit tests to the metadata precomputation. I also made layer 30 only do the minimal metadata precomputation it needs for the concepts introduced until then. In the process, I also made the precomputation more correct than before, and added hooks in the right place so that I could augment the logic when I introduced shape-shifting containers. == lessons learned There's several levels of hygiene when it comes to layers: 1. Every layer introduces precisely what it needs and in the simplest way possible. If I was building an app until just that layer, nothing would seem over-engineered. 2. Some layers are fore-shadowing features in future layers. Sometimes this is ok. For example, layer 10 foreshadows containers and arrays and so on without actually supporting them. That is a net win because it lets me lay out the core of Mu's data structures out in one place. But if the fore-shadowing gets too complex things get nasty. Not least because it can be hard to write unit tests for features before you provide the plumbing to visualize and manipulate them. 3. A layer is introducing features that are tested only in later layers. 4. A layer is introducing features with tests that are invalidated in later layers. (This I knew from early on to be an obviously horrendous idea.) Summary: avoid Level 2 (foreshadowing layers) as much as possible. Tolerate it indefinitely for small things where the code stays simple over time, but become strict again when things start to get more complex. Level 3 is mostly a net lose, but sometimes it can be expedient (a real case of the usually grossly over-applied term "technical debt"), and it's better than the conventional baseline of no layers and no scenarios. Just clean it up as soon as possible. Definitely avoid layer 4 at any time. == minor lessons Avoid unit tests for trivial things, write scenarios in context as much as possible. But within those margins unit tests are fine. Just introduce them before any scenarios (commit 3297). Reorganizing layers can be easy. Just merge layers for starters! Punt on resplitting them in some new way until you've gotten them to work. This is the wisdom of Refactoring: small steps. What made it hard was not wanting to merge *everything* between layer 30 and 55. The eventual insight was realizing I just need to move those two full-strength transforms and nothing else.
* 3305 - show all available precision in numbersKartik K. Agaram2016-09-081-0/+1
| | | | | | | | | | | | | | | Thanks Ella Couch for pointing out that Mu was lying when debugging small numbers. def main [ local-scope x:number <- copy 1 { x <- divide x, 2 $print x, 10/newline loop # until SIGFPE } ]
* 3293Kartik K. Agaram2016-09-021-1/+4
|
* 3292Kartik K. Agaram2016-09-021-12/+12
|
* 3286Kartik K. Agaram2016-08-311-1/+21
|
* 3285Kartik K. Agaram2016-08-311-0/+1
|
* 3279Kartik K. Agaram2016-08-291-1/+1
| | | | | Stop inlining functions because that will complicate separate compilation. It also simplifies the code without impacting performance.
* 3273Kartik K. Agaram2016-08-281-2/+2
| | | | | | | | | | | Undo 3272. The trouble with creating a new section for constants is that there's no good place to order it since constants can be initialized using globals as well as vice versa. And I don't want to add constraints disallowing either side. Instead, a new plan: always declare constants in the Globals section using 'extern const' rather than just 'const', since otherwise constants implicitly have internal linkage (http://stackoverflow.com/questions/14894698/why-does-extern-const-int-n-not-work-as-expected)
* 3272Kartik K. Agaram2016-08-281-1/+1
| | | | | | Move global constants into their own section since we seem to be having trouble linking in 'extern const' variables when manually cleaving mu.cc into separate compilation units.
* 3267Kartik K. Agaram2016-08-281-2/+0
|
* 3260Kartik K. Agaram2016-08-261-6/+6
| | | | | array length = number of elements array size = in locations
* 3101 - purge .traces/ dir from repo historyKartik K. Agaram2016-07-051-2/+1
| | | | | | | | | | | | | | | | | | | | | I'd been toying with this idea for some time now given how large the repo had been growing. The final straw was noticing that people cloning the repo were having to wait *5 minutes*! That's not good, particularly for a project with 'tiny' in its description. After purging .traces/ clone time drops to 7 seconds in my tests. Major issue: some commits refer to .traces/ but don't really change anything there. That could get confusing :/ Minor issues: a) I've linked inside commits on GitHub like a half-dozen times online or over email. Those links are now liable to eventually break. (I seem to recall GitHub keeps them around as long as they get used at least once every 60 days, or something like that.) b) Numbering of commits is messed up because some commits only had changes to the .traces/ sub-directory.
* 3083Kartik K. Agaram2016-07-011-3/+8
|
* 3027Kartik K. Agaram2016-06-021-2/+2
|
* 3009Kartik K. Agaram2016-05-251-2/+6
|
* 3008Kartik K. Agaram2016-05-251-2/+2
|
* 2968Kartik K. Agaram2016-05-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | More reorganization in preparation for implementing recursive abandon(). Refcounts are getting incredibly hairy. I need to juggle containers containing other containers, and containers *pointing* to other containers. For a while I considered getting rid of address_element_info entirely and just going by types for every single update_refcount. But that's definitely more work, and it's unclear that things will be cleaner/shorter/simpler. I haven't measured the speedup, but it seems worth optimizing every pointer copy to make sure we aren't manipulating types at runtime. The key insight now is a) to continue to compute information about nested containers at load time, because that's the common case when updating refcounts, but b) to compute information about *pointed* values at run-time, because that's the uncommon case. As a result, we're going to cheat in the interpreter and use type information at runtime just for abandon(), just because the corresponding task when we get to a compiler will be radically different. It will still be tractable, though.
* 2967Kartik K. Agaram2016-05-171-17/+17
|
* 2931 - be explicit about making copiesKartik K. Agaram2016-05-061-1/+1
|
* 2891 - precompute container sizes and offsetsKartik K. Agaram2016-05-021-0/+3
| | | | | | | It's a bit of a trade-off because we need to store copies of container metadata in each reagent (to support shape-shifting containers), and metadata is not lightweight and will get heavier. But it'll become more unambiguously useful when we switch to a compiler.
* 2882 - warn if programmer overuses transform_all()Kartik K. Agaram2016-04-281-1/+3
| | | | | | | | | | | | | | | | | | | | This continues a line of thought sparked in commit 2831. I spent a while trying to avoid calling size_of() at transform-time, but there's no getting around the fact that translating names to addresses requires knowing how much space they need. This raised the question of what happens if the size of a container changes after a recipe using it is already transformed. I could go down the road of trying to detect such situations and redoing work, but that massively goes against the grain of my original design, which assumed that recipes don't get repeatedly transformed. Even though we call transform_all() in every test, in a non-testing run we should be loading all code and calling transform_all() just once to 'freeze-dry' everything. But even if we don't want to support multiple transforms it's worth checking that they don't occur. This commit does so in just one situation. There are likely others.
* 2856Kartik K. Agaram2016-04-231-1/+1
|
* 2818Kartik K. Agaram2016-03-281-2/+1
|
* 2816Kartik K. Agaram2016-03-271-1/+1
| | | | Move all bounds checks for types and recipes to one place.
* 2803Kartik K. Agaram2016-03-211-8/+28
| | | | | Show more thorough information about instructions in the trace, but keep the original form in error messages.
* 2799 - new approach to undoing changes in testsKartik K. Agaram2016-03-201-0/+30
| | | | | | | | As outlined at the end of 2797. This worked out surprisingly well. Now the snapshotting code touches fewer layers, and it's much better behaved, with less need for special-case logic, particularly inside run_interactive(). 30% slower, but should hopefully not cause any more bugs.
* 2773 - switch to 'int'Kartik K. Agaram2016-03-131-20/+20
| | | | This should eradicate the issue of 2771.
* 2694Kartik K. Agaram2016-02-231-1/+1
|
* 2692 - all memory leaks fixedKartik K. Agaram2016-02-231-1/+3
| | | | | | | | | | To find this I spent some time trying to diagnose when it happened but there was no seeming pattern. I'd ended up with a small single-file .cc and single-file .mu that reproduced one memory leak. Eventually I tried deleting all type_tree and string_tree from it, and lo the leaks vanished. I retried on all of edit (just loading), and the leaks remained gone. At that point I switched tack and started looking at all the core methods of these classes.
* 2688Kartik K. Agaram2016-02-221-4/+0
|
* 2687Kartik K. Agaram2016-02-221-1/+1
|
* 2681 - drop reagent types from reagent propertiesKartik K. Agaram2016-02-211-43/+81
| | | | | | | | | | | | | | | | | All my attempts at staging this change failed with this humongous commit that took all day and involved debugging three monstrous bugs. Two of the bugs had to do with forgetting to check the type name in the implementation of shape-shifting recipes. Bug #2 in particular would cause core tests in layer 59 to fail -- only when I loaded up edit/! It got me to just hack directly on mu.cc until I figured out the cause (snapshot saved in mu.cc.modified). The problem turned out to be that I accidentally saved a type ingredient in the Type table during specialization. Now I know that that can be very bad. I've checked the traces for any stray type numbers (rather than names). I also found what might be a bug from last November (labeled TODO), but we'll verify after this commit.
* 2679Kartik K. Agaram2016-02-201-22/+0
|