[PATCH] D74736: [ELF] Ignore the maximum of input section alignments for two cases

[Peter Smith via Phabricator via llvm-commits]

psmith added a comment.

I agree with the specification of the change, I'm not sure why there is a change in Writer.cpp yet, if there is a good reason and it isn't obvious it will be worth a comment.



================
Comment at: lld/ELF/Writer.cpp:2219
+      return;
+    cmd->alignExpr = [align = cmd->alignment]() { return align; };
+    if (!cmd->addrExpr) {
----------------
I'm struggling a bit with this one from the just the context. As far as I can tell there are only two uses of AlignExpr, in switchTo and in 
`void LinkerScript::adjustSectionsBeforeSorting()`
````
    // Handle align (e.g. ".foo : ALIGN(16) { ... }").
    if (sec->alignExpr)
      sec->alignment =
          std::max<uint32_t>(sec->alignment, sec->alignExpr().getValue());
```
In both cases I can't easily see why adding `cmd->alignExpr = [align = cmd->alignment]() { return align; };` would change the calculated alignment. For example `sec->alignment` should be the same as `alignExpr().getValue()` and in `switchTo`

```
uint32_t align =
        sec->alignExpr ? sec->alignExpr().getValue() : ctx->outSec->alignment;
```
When there isn't alignExpr isn't `ctx->outSec->alignment` the same as `alignExpr.getValue()`?

Can you let me know if I'm missing something?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D74736/new/

https://reviews.llvm.org/D74736