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e2f06cce94
The regular obfuscation process simply modifies some simple nodes, such as identifiers and strings. In those cases, we modify the nodes in-place, meaning that their positions remain the same. This hasn't caused any problems. Literal obfuscation is trickier. Since we replace one expression with an entirely different one, we use cursor.Replace. The new expression is entirely made up on the spot, so it lacks position information. This was causing problems. For example, in the added test input: > garble -literals build [stderr] # test/main dgcm4t6w.go:3: misplaced compiler directive dgcm4t6w.go:4: misplaced compiler directive dgcm4t6w.go:3: misplaced compiler directive dgcm4t6w.go:6: misplaced compiler directive dgcm4t6w.go:7: misplaced compiler directive dgcm4t6w.go:3: misplaced compiler directive dgcm4t6w.go:9: misplaced compiler directive dgcm4t6w.go:3: misplaced compiler directive dgcm4t6w.go:3: too many errors The build errors are because we'd move the compiler directives, which makes the compiler unhappy as they must be directly followed by a function declaration. The root cause there seems to be that, since the replacement nodes lack position information, go/printer would try to estimate its printing position by adding to the last known position. Since -literals adds code, this would result in the printer position increasing rapidly, and potentially printing directive comments earlier than needed. For now, making the replacement nodes have the same position as the original node seems to stop go/printer from making this mistake. It's possible that this workaround won't be bulletproof forever, but it works well for now, and I don't see a simpler workaround right now. It would be possible to use fancier mechanisms like go/ast.CommentMap or dave/dst, but those are a significant amount of added complexity as well. Fixes #285. |
5 years ago | |
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| bench-cache | 5 years ago | |
| bench-nocache | 5 years ago | |
| mod | 5 years ago | |
| scripts | 5 years ago | |