Don't error if we don't have line information (#634)

* Don't error if we don't have line information

`whereis` is already allowed to return `nothing`. It's possible for codeloc to be != 0,
but for Core.Compiler to still be unable to produce a location. In that case, also
return `nothing`.

* propagate the `nothing` case

---------

Co-authored-by: Tim Holy <[email protected]>

Author: Keno

src/interpret.jl

@@ -457,23 +457,25 @@ function coverage_visit_line!(frame::Frame)
     code.report_coverage || return
     src = code.src
     @static if VERSION ≥ v"1.12.0-DEV.173"
-    lineinfo = linetable(src, pc)
-    file, line = lineinfo.file, lineinfo.line
-    if line != frame.last_codeloc
-        file isa Symbol || (file = Symbol(file)::Symbol)
-        @ccall jl_coverage_visit_line(file::Cstring, sizeof(file)::Csize_t, line::Cint)::Cvoid
-        frame.last_codeloc = line
-    end
+        lineinfo = linetable(src, pc)
+        if lineinfo !== nothing
+            file, line = lineinfo.file, lineinfo.line
+            if line != frame.last_codeloc
+                file isa Symbol || (file = Symbol(file)::Symbol)
+                @ccall jl_coverage_visit_line(file::Cstring, sizeof(file)::Csize_t, line::Cint)::Cvoid
+                frame.last_codeloc = line
+            end
+        end
     else # VERSION < v"1.12.0-DEV.173"
-    codeloc = src.codelocs[pc]
-    if codeloc != frame.last_codeloc && codeloc != 0
-        linetable = src.linetable::Vector{Any}
-        lineinfo = linetable[codeloc]::Core.LineInfoNode
-        file, line = lineinfo.file, lineinfo.line
-        file isa Symbol || (file = Symbol(file)::Symbol)
-        @ccall jl_coverage_visit_line(file::Cstring, sizeof(file)::Csize_t, line::Cint)::Cvoid
-        frame.last_codeloc = codeloc
-    end
+        codeloc = src.codelocs[pc]
+        if codeloc != frame.last_codeloc && codeloc != 0
+            linetable = src.linetable::Vector{Any}
+            lineinfo = linetable[codeloc]::Core.LineInfoNode
+            file, line = lineinfo.file, lineinfo.line
+            file isa Symbol || (file = Symbol(file)::Symbol)
+            @ccall jl_coverage_visit_line(file::Cstring, sizeof(file)::Csize_t, line::Cint)::Cvoid
+            frame.last_codeloc = codeloc
+        end
     end # @static if
 end
 

src/utils.jl

@@ -277,12 +277,14 @@ function linetable(arg)
     return ci.linetable::Union{Vector{Core.LineInfoNode},Vector{Any}} # issue #264
     end # @static if
 end
-function linetable(arg, i::Integer; macro_caller::Bool=false)::Union{Expr,LineTypes}
+function linetable(arg, i::Integer; macro_caller::Bool=false)::Union{Expr,Nothing,LineTypes}
     lt = linetable(arg)
     @static if VERSION ≥ v"1.12.0-DEV.173"
     # TODO: decode the linetable at this frame efficiently by reimplementing this here
     # TODO: get the contextual name from the parent, rather than returning "n/a" (which breaks Cthulhu)
-    return Base.IRShow.buildLineInfoNode(lt, :var"n/a", i)[1] # ignore all inlining / macro expansion / etc :(
+    nodes = Base.IRShow.buildLineInfoNode(lt, :var"n/a", i)
+    isempty(nodes) && return nothing
+    return nodes[1] # ignore all inlining / macro expansion / etc :(
     else # VERSION < v"1.12.0-DEV.173"
     lin = lt[i]::Union{Expr,LineTypes}
     if macro_caller
@@ -351,9 +353,10 @@ function lineoffset(framecode::FrameCode)
     return offset
 end
 
-function getline(ln::Union{LineTypes,Expr})
+function getline(ln::Union{LineTypes,Expr,Nothing})
     _getline(ln::LineTypes) = Int(ln.line)
     _getline(ln::Expr)      = ln.args[1]::Int # assuming ln.head === :line
+    _getline(::Nothing)     = nothing
     return _getline(ln)
 end
 function getfile(ln::Union{LineTypes,Expr})
@@ -387,6 +390,7 @@ function CodeTracking.whereis(framecode::FrameCode, pc::Int; kwargs...)
     codeloc = codelocation(framecode.src, pc)
     codeloc == 0 && return nothing
     lineinfo = linetable(framecode, codeloc; kwargs...)
+    lineinfo === nothing && return nothing
     m = framecode.scope
     return isa(m, Method) ? whereis(lineinfo, m) : (getfile(lineinfo), getline(lineinfo))
 end