CodeView, like most other debug formats, represents the live range of a
variable so that debuggers might print them out.
They use a variety of records to represent how a particular variable
might be available (in a register, in a frame pointer, etc.) along with
a set of ranges where this debug information is relevant.
However, the format only allows us to use ranges which are limited to a
maximum of 0xF000 in size. This means that we need to split our debug
information into chunks of 0xF000.
Because the layout of code is not known until *very* late, we must use a
new fragment to record the information we need until we can know
*exactly* what the range is.
llvm-svn: 259868
CodeView requires us to accurately describe the extent of the inlined
code. We did this by grabbing the next debug location in source order
and using *that* to denote where we stopped inlining. However, this is
not sufficient or correct in instances where there is no next debug
location or the next debug location belongs to the start of another
function.
To get this correct, use the end symbol of the function to denote the
last possible place the inlining could have stopped at.
llvm-svn: 259548
This directive emits the binary annotations that describe line and code
deltas in inlined call sites. Single-stepping through inlined frames in
windbg now works.
llvm-svn: 259535
If a target can only emit 8-bits data, we would loop in EmitValueImpl
since it will try to split a 32-bits data in 1 chunk of 32-bits.
No test since all current targets can emit 32bits at a time.
Patch by Alexandru Guduleasa!
llvm-svn: 259399
Changed emitting offset of macinfo entry into compiler unit DIE to use "addSectionLabel" method rather than explicitly calculating size/offset of macro entry.
Differential Revision: http://reviews.llvm.org/D16292
llvm-svn: 259358
With poorly chosen custom parameters, the line table encoding logic would
sometimes end up generating a special opcode bigger than 255, which is wrong.
The set of default parameters that LLVM uses isn't subject to this bug.
When carefully chosing the line table parameters, it's impossible to fall into the
corner case that this patch fixes. The standard however doesn't require that these
parameters be carefully chosen. And even if it did, we shouldn't generate broken
encoding.
Add a unittest for this specific encoding bug, and while at it, create some unit
tests for the encoding logic using different sets of parameters.
llvm-svn: 259334
This support is _very_ rudimentary, just enough to get some basic data
into the CodeView debug section.
Left to do is:
- Use the combined opcodes to save space.
- Do something about code offsets.
llvm-svn: 259230
Summary:
There are three parts to inlined call frames:
1. The inlinee line subsection
2. The inline site symbol record
3. The function ids referenced by both
This change starts by emitting function ids (3) for all subprograms and
emitting the base inline site symbol record (2). The actual line numbers
in (2) use an encoded format that will come next, along with the inlinee
line subsection.
Reviewers: majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16333
llvm-svn: 259217
I don't seem to see these locally, maybe just need to update my
compiler, or we haven't turned them on for LLVM's build and we should...
llvm-svn: 259146
This reverts commit r259117.
The LineInfo constructor is defined in the codeview library and we have
to link against it now. Doing that isn't trivial, so reverting for now.
llvm-svn: 259126
Adds a new family of .cv_* directives to LLVM's variant of GAS syntax:
- .cv_file: Similar to DWARF .file directives
- .cv_loc: Similar to the DWARF .loc directive, but starts with a
function id. CodeView line tables are emitted by function instead of
by compilation unit, so we needed an extra field to communicate this.
Rather than overloading the .loc direction further, we decided it was
better to have our own directive.
- .cv_stringtable: Emits the codeview string table at the current
position. Currently this just contains the filenames as
null-terminated strings.
- .cv_filechecksums: Emits the file checksum table for all files used
with .cv_file so far. There is currently no support for emitting
actual checksums, just filenames.
This moves the line table emission code down into the assembler. This
is in preparation for implementing the inlined call site line table
format. The inline line table format encoding algorithm requires knowing
the absolute code offsets, so it must run after the assembler has laid
out the code.
David Majnemer collaborated on this patch.
llvm-svn: 259117
Various bits we want to use the new ABI actually compile with "-arch armv7k
-miphoneos-version-min=9.0". Not ideal, but also not ridiculous given how
slices work.
llvm-svn: 258975
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html
"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi
Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark
Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D16471
llvm-svn: 258861
For historic reasons, the behavior of .align differs between targets.
Fortunately, there are alternatives, .p2align and .balign, which make the
interpretation of the parameter explicit, and which behave consistently across
targets.
This patch teaches MC to use .p2align instead of .align, so that people reading
code for multiple architectures don't have to remember which way each platform
does its .align directive.
Differential Revision: http://reviews.llvm.org/D16549
llvm-svn: 258750
Consolidate the code which handles string table offsets less than 999999
with the code for offsets less than 9999999. While we are here,
simplify the code by not using sprintf to generate the string.
llvm-svn: 258664
When a symbol S shows up in an expression in assembly there are two
possible interpretations
* The expression is referring to the value of S in this file.
* The expression is referring to the value after symbol resolution.
In the first case the assembler can reason about the value and try to
produce a relocation.
In the second case, that is only possible if the symbol cannot be
preempted.
Assemblers are not very consistent about which interpretation gets used.
This changes MC to agree with GAS in the case of an expression of the
form "Sym - WeakSym".
llvm-svn: 258329
The value size was always 1 or 0, so we don't need to store it.
In a no asserts build this takes the testcase of pr26208 from 11 to 10
seconds.
llvm-svn: 258141
WebAssembly's stack will never be executable by default, so it isn't
necessary to declare .note.GNU-stack sections to request a non-executable
stack.
Differential Revision: http://reviews.llvm.org/D15969
llvm-svn: 257962
This method has no callers.
Also remove X86ELFRelocationInfo.cpp and X86MachORelocationInfo.cpp
which only existed to provide an implementation of that method.
Ok'd by Rafael and Jim.
llvm-svn: 257859
Currently WebAssembly has two kinds of relocations; data addresses and
function addresses. This adds ELF relocations for them, as well as an
MC symbol kind to indicate which type of relocation is needed.
llvm-svn: 257416
LLVM_ENABLE_TIMESTAMPS controls if timestamps are embedded into llvm's
binaries. Turning it off is useful for deterministic builds.
r246905 made it so that the define suddenly also controls if the binaries that
the llvm binaries _create_ embed timestamps or not – but this shouldn't be a
configure-time option. r256203/r256204 added a driver option to toggle this on
and off, so this patch now passes this driver option in LLVM_ENABLE_TIMESTAMPS
builds so that if LLVM_ENABLE_TIMESTAMPS is set, the build of LLVM is
deterministic – but the built clang can still write timestamps into other
executables when requested.
This also allows removing some of the test machinery added in r292012 to work
around this problem.
See PR24740 for background.
http://reviews.llvm.org/D15783
llvm-svn: 256958
SubtargetFeatures::ApplyFeatureFlag to be static, so that
MCSubtargetInfo doesn't need to instantiate SubtargetFeatures
for nothing. Also change the return type to void, as it
wasn't ever used.
This is a partial commit of http://reviews.llvm.org/D15746
llvm-svn: 256823
of casting the integer '4' to such a pointer. There is no reason to
expect '4' to be a portable or reliable pointer of this form. The only
reason this ever worked is because the PointerIntPair that this actually
gets used with has an artificially *low* presumed alignment that allowed
it to work. When the alignment of PointerIntPair is derived from the
actual type's alignment, the asserts start firing on this pointer. I'm
amazed we never managed to do anything that triggered the alignment
sanitizer with it, as this is just flat out UB.
If folks dislike this approach to providing a sentinel fragment address,
there are a myriad of other alternatives, suggestions welcome. But this
one has the distinct advantage of not requiring the friend dance of
ilist's sentinel (which I'll point out is *also* in play for
MCFragment!) and seems to be using a nicely provided facility in
MCFragment to establish just such dummy nodes.
This is part of a series of patches to allow LLVM to check for complete
pointee types when computing its pointer traits. This is absolutely
necessary to get correct (or reproducible) results for things like how
many low bits are guaranteed to be zero.
llvm-svn: 256552
header to its own header, allowing users of fragments to have a narrower
header file, and avoid circular header dependencies when getting the
definition of MCSection prior to inspecting traits on MCSection
pointers.
This is part of a series of patches to allow LLVM to check for complete
pointee types when computing its pointer traits. This is absolutely
necessary to get correct (or reproducible) results for things like how
many low bits are guaranteed to be zero.
Note that this doesn't in any way change the design of MC, it is just
moving code around to allow the *header files* to be more fine grained.
Without this, it is impossible to get a complete type for MCSection
where it is needed.
If anyone would prefer a different slicing of the header files, I'm
happy to oblige of course. =]
llvm-svn: 256548
MCDwarf emits a canned abbreviation table, but was not emitting proper
forms for DWARF version 4, which is the default after r249655.
Differential Revision: http://reviews.llvm.org/D15732
llvm-svn: 256313
InitMCObjectFileInfo was trying to override the triple in awkward ways.
For example, a triple specifying COFF but not Windows was forced as ELF.
This makes it easy for internal invariants to get violated, such as
those which triggered PR25912.
This fixes PR25912.
llvm-svn: 256226
Today, we always take into account the possibility that object files
produced by MC may be consumed by an incremental linker. This results
in us initialing fields which vary with time (TimeDateStamp) which harms
hermetic builds (e.g. verifying a self-host went well) and produces
sub-optimal code because we cannot assume anything about the relative
position of functions within a section (call sites can get redirected
through incremental linker thunks).
Let's provide an MCTargetOption which controls this behavior so that we
can disable this functionality if we know a-priori that the build will
not rely on /incremental.
llvm-svn: 256203
David Majnemer