[llvm] [llvm-objdump] Add --substitute-path and --source-dir for --source (PR #201096)

[James Henderson via llvm-commits]

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@@ -4,13 +4,13 @@
 ;; lives in this test's Inputs directory. Without path remapping, --source
 ;; cannot load the file from disk.
 ;;
-;; --source-dir: each flag is prepended to the search list, so later flags on
-;; the command line are tried first.
+;; --source-dir: one directory per flag; later flags on the command line are
+;; searched before earlier ones.
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jh7370 wrote:

If I'm following things, the difference here is that with llvm-objdump you have to specify all the options upfront when invoking the tool, whereas in GDB, you specify them one at a time, potentially at vastly different points in the debugging process (with the ability to reset in between).

Given this, I think we need to go with the precedent of other similar options in non-interactive tools, i.e. first to last processing. See for example the --debug-file-directory, which is conceptually similar to this option. That uses first to last sequencing.

https://github.com/llvm/llvm-project/pull/201096