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| author | Luke Wagner <mail@lukewagner.name> | 2015-09-11 17:27:33 -0500 |
|---|---|---|
| committer | Luke Wagner <mail@lukewagner.name> | 2015-09-15 11:27:22 -0500 |
| commit | a812e9fe429e31dfd71bbabf7d7a37771fe71e8e (patch) | |
| tree | 63a5540c64c8d60a37db4a79daf30e535f393188 /DynamicLinking.md | |
| parent | 1f05c4cdbc0dc51952579dfbaba3a7a7ce710562 (diff) | |
| download | nanowasm-design-a812e9fe429e31dfd71bbabf7d7a37771fe71e8e.tar.gz | |
Move globals out of the MVP
Diffstat (limited to 'DynamicLinking.md')
| -rw-r--r-- | DynamicLinking.md | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/DynamicLinking.md b/DynamicLinking.md index 675471f..f110d8f 100644 --- a/DynamicLinking.md +++ b/DynamicLinking.md @@ -10,6 +10,17 @@ dynamic libraries. WebAssembly will support both load-time and run-time (`dlopen`) dynamic linking of libraries. +One important requirement of dynamic linking is to allow the linked module +to have its own position-independent global data segment. This could be achieved +by specifying a new kind of link-time-initialized immutable global variable +which would be initialized with the address (in linear memory) of the modules' +global data segment. These immutable globals could also be used to provide +a linked module with the offsets of its function pointers in the instance's +function pointer tables. An important aspect of immutable globals is that they +could either be patched directly as constant values or implemented through a +[Global Offset Table](https://en.wikipedia.org/wiki/Position-independent_code) +in position-independent code. + Dynamic linking is especially useful when combined with a Content Distribution Network (CDN) such as [hosted libraries][] because the library is only ever downloaded and compiled once per user device. It can also allow for smaller |