This patch adds a new "target.auto-deduce-source-map" setting. If enabled, this setting may auto deduce a source map entry based on requested breakpoint path and the original path stored in debug info for resolved breakpoint. As an example, if debug info contains "./a/b/c/main.cpp", user sets a source breakpoint at "/root/repo/x/y/z/a/b/c/main.cpp". The breakpoint will resolve correctly now with Greg's patch https://reviews.llvm.org/D130401. However, the resolved breakpoint will use "./a/b/c/main.cpp" to locate source file during stop event which would fail most of the time. With the new "target.auto-deduce-source-map" setting enabled, a auto deduced source map entry "." => "/root/repo/x/y/z" will be added. This new mapping will help lldb to map resolved breakpoint path "./a/b/c/main.cpp" back to "/root/repo/x/y/z/a/b/c/main.cpp" and locate it on disk. If an existing source map entry is used the patch also concatenates the auto deduced entry with any stripped reverse mapping prefix (see example below). As a second example, debug info contains "./a/b/c/main.cpp" and user sets breakpoint at "/root/repo/x/y/z/a/b/c/main.cpp". Let's say there is an existing source map entry "." => "/root/repo"; this mapping would strip the prefix out of "/root/repo/x/y/z/a/b/c/main.cpp" and use "x/y/z/a/b/c/main.cpp" to resolve breakpoint. "target.auto-deduce-source-map" setting would auto deduce a new potential mapping of "." => "x/y/z", then it detects that there is a stripped prefix from reverse mapping and concatenates it as the new mapping: "." => "/root/repo/x/y/z" which would correct map "./a/b/c/main.cpp" path to new path in disk. This patches depends on https://reviews.llvm.org/D130401 to use new added SBTarget::GetSourceMap() API for testing. Differential Revision: https://reviews.llvm.org/D133042
We also inject a source-map behind the scenes when a dSYM has path mapping keys as described in:
It would be good to make sure that the auto-detect source maps and that feature get along nicely both when the dSYM source map points to the right directory, and when it to is stale and points to some path that's not available.