Summary:
This patch attempts to solve two issues made this code hard to follow
for me.
The first issue was that a lot of what these visitors do is mutate the
AST. The visitor pattern is not particularly good for that because by
the time you have performed the dynamic type dispatch, it's too late to
go back to the parent node, and change its pointer. The previous code
dealt with that relatively elegantly, but it still meant that one had to
perform manual type checks, which is what the visitor pattern is
supposed to avoid.
The second issue was not being able to return values from the Visit
functions, which meant that one had to store function results in member
variables (a common problem with visitor patterns).
Here, I solve both problems by making the visitor use a type switch
instead of going through double dispatch on the visited object. This
allows one to parameterize the visitor based on the return type and pass
function results as function results. The mutation is fascilitated by
having each Visit function take two arguments -- a reference to the
object itself (with the correct dynamic type), and a reference to the
parent's pointer to this object.
Although this wasn't my explicit goal here, the fact that we're not
using virtual dispatch anymore allows us to make the AST nodes
trivially destructible, which is a good thing, since we were not
destroying them anyway.
Reviewers: aleksandr.urakov, amccarth
Subscribers: lldb-commits
Differential Revision: https://reviews.llvm.org/D60410
llvm-svn: 358261
Summary:
The code was passing pointers around, expecting they would be not null.
In c++ it is possible to convey this notion explicitly by using a
reference instead.
Not all uses of pointers could be converted to references (e.g. one
can't store references in a container), but this will at least make it
locally obvious that code is dealing with nonnull pointers.
Reviewers: aleksandr.urakov, amccarth
Subscribers: lldb-commits
Differential Revision: https://reviews.llvm.org/D60271
llvm-svn: 357744
Summary:
This refactors moves the register name->number resolution out of the
FPOProgramNodeRegisterRef class. Instead I create a special
FPOProgramNodeSymbol class, which holds unresolved symbols, and move the
resolution into the ResolveRegisterRefs visitor.
The background here is that I'd like to use this code for Breakpad
unwind info, which uses similar syntax to describe unwind info. For
example, a simple breakpad unwind program might look like:
.cfa: $esp 8 + $ebp: .cfa 8 - ^
To be able to do this, I need to be able to customize register
resolving, as that is presently hardcoded to use codeview register
names, but breakpad supports a lot more architectures with different
register names. Moving the resolution into a separate class will allow
each user to use a different resolution logic.
Reviewers: aleksandr.urakov, zturner, amccarth
Subscribers: jdoerfert, lldb-commits
Differential Revision: https://reviews.llvm.org/D60068
llvm-svn: 357455
stored relative to VFRAME
Summary:
This patch makes LLDB able to retrieve proper values for function arguments and
local variables stored in PDB relative to VFRAME register.
Patch contains retrieval of corresponding FPO table entries from PDB and a
generic translator from FPO programs to DWARF expressions to get correct VFRAME
value.
Patch also improves variables-locations.test and makes this test passable on
x86.
Patch By: leonid.mashinsky
Reviewers: zturner, asmith, stella.stamenova, aleksandr.urakov
Reviewed By: zturner
Subscribers: arphaman, labath, mgorny, aprantl, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D55122
llvm-svn: 352845
