This adds a -debugify-each mode to opt which, when enabled, wraps each
{Module,Function}Pass in a pipeline with logic to add, check, and strip
synthetic debug info for testing purposes.
This mode can be used to test complex pipelines for debug info bugs, or
to collect statistics about the number of debug values & locations lost
throughout various stages of a pipeline.
Patch by Son Tuan Vu!
Differential Revision: https://reviews.llvm.org/D46525
llvm-svn: 332312
Summary:
If we are not emitting a linkage name in the .debug_info sections, we
should not add it into the index either. This makes sure our index is
consistent with the actual debug info.
I am also explicitly setting the --dwarf-linkage-names=All in the
name-collsions test as that one would now fail on targets where this
defaults to "Abstract" (in fact, it would have failed already if there
wasn't a bug in the DWARF verifier, which I fix as well).
Reviewers: probinson, aprantl, JDevlieghere
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46748
llvm-svn: 332246
length excluding the table header. Instead it must encode the contribution length minus the length
field itself.
Reviewer: JDevliegehere
Differential Revision: https://reviews.llvm.org/D45922
llvm-svn: 332030
Summary: The final -wasm component has been the default for some time now.
Subscribers: jfb, dschuff, jgravelle-google, eraman, aheejin, JDevlieghere, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D46342
llvm-svn: 332007
Reviewed by: dblaikie, JDevlieghere, espindola
Differential Revision: https://reviews.llvm.org/D44560
Summary:
The .debug_line parser previously reported errors by printing to stderr and
return false. This is not particularly helpful for clients of the library code,
as it prevents them from handling the errors in a manner based on the calling
context. This change switches to using llvm::Error and callbacks to indicate
what problems were detected during parsing, and has updated clients to handle
the errors in a location-specific manner. In general, this means that they
continue to do the same thing to external users. Below, I have outlined what
the known behaviour changes are, relating to this change.
There are two levels of "errors" in the new error mechanism, to broadly
distinguish between different fail states of the parser, since not every
failure will prevent parsing of the unit, or of subsequent unit. Malformed
table errors that prevent reading the remainder of the table (reported by
returning them) and other minor issues representing problems with parsing that
do not prevent attempting to continue reading the table (reported by calling a
specified callback funciton). The only example of this currently is when the
last sequence of a unit is unterminated. However, I think it would be good to
change the handling of unrecognised opcodes to report as minor issues as well,
rather than just printing to the stream if --verbose is used (this would be a
subsequent change however).
I have substantially extended the DwarfGenerator to be able to handle
custom-crafted .debug_line sections, allowing for comprehensive unit-testing
of the parser code. For now, I am just adding unit tests to cover the basic
error reporting, and positive cases, and do not currently intend to test every
part of the parser, although the framework should be sufficient to do so at a
later point.
Known behaviour changes:
- The dump function in DWARFContext now does not attempt to read subsequent
tables when searching for a specific offset, if the unit length field of a
table before the specified offset is a reserved value.
- getOrParseLineTable now returns a useful Error if an invalid offset is
encountered, rather than simply a nullptr.
- The parse functions no longer use `WithColor::warning` directly to report
errors, allowing LLD to call its own warning function.
- The existing parse error messages have been updated to not specifically
include "warning" in their message, allowing consumers to determine what
severity the problem is.
- If the line table version field appears to have a value less than 2, an
informative error is returned, instead of just false.
- If the line table unit length field uses a reserved value, an informative
error is returned, instead of just false.
- Dumping of .debug_line.dwo sections is now implemented the same as regular
.debug_line sections.
- Verbose dumping of .debug_line[.dwo] sections now prints the prologue, if
there is a prologue error, just like non-verbose dumping.
As a helper for the generator code, I have re-added emitInt64 to the
AsmPrinter code. This previously existed, but was removed way back in r100296,
presumably because it was dead at the time.
This change also requires a change to LLD, which will be committed separately.
llvm-svn: 331971
Make these two test cases more generic for other architectures.
Please refer to '[DebugInfo] Convert intrinsic llvm.dbg.label to
MachineInstr.'
Patch by Hsiangkai Wang
llvm-svn: 331853
Please refer to '[DebugInfo] Add DILabel metadata and intrinsic
llvm.dbg.label'. I have renamed the 'variables' attributes to
'retainedNodes' to include local variables and local labels for the
function.
Patch by Hsiangkai Wang.
llvm-svn: 331848
In order to convert LLVM IR to MachineInstr, we need a new TargetOpcode,
DBG_LABEL, to ‘lower’ intrinsic llvm.dbg.label. The patch
creates this new TargetOpcode and convert intrinsic llvm.dbg.label to
MachineInstr through SelectionDAG.
In SelectionDAG, debug information is stored in SDDbgInfo. We create a
new data member of SDDbgInfo for labels and use the new data member,
SDDbgLabel, to create DBG_LABEL MachineInstr.
The new DBG_LABEL MachineInstr uses label metadata from LLVM IR as its
parameter. So, the backend could get metadata information of labels from
DBG_LABEL MachineInstr.
Differential Revision: https://reviews.llvm.org/D45341
Patch by Hsiangkai Wang.
llvm-svn: 331842
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
Before SVN r244158, codeview debug info was emitted always
emitted for msvc if debug info was enabled, but that commit
added a module flag.
Since it's still restricted by the flag, we can allow it
for any target if the user requests it, not only msvc (and
windows-itanium, added in SVN r287567).
Add a test for emitting it for a mingw target.
Differential Revision: https://reviews.llvm.org/D46303
llvm-svn: 331809
Summary:
getNode optimizes (ext (trunc x)) to x and the dbgvalue node on trunc is lost. The fix calls transferDbgValues to add the dbgvalue to x.
Add DebugInfo/AArch64/dbg-value-i16.ll
Patch by Sejong Oh!
Reviewers: aprantl, javed.absar, llvm-commits, vsk
Reviewed By: aprantl, vsk
Subscribers: kristof.beyls, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D46348
llvm-svn: 331665
Summary:
This reverts SVN r331441 (reapplies r331337), together with a fix
in to handle an already existing fragment expression in the
dbg.value that must be fragmented due to a split PHI node.
This should solve the problem seen in PR37321, which was the
reason for the revert of r331337.
The situation in PR37321 is that we have a PHI node like this
%u.sroa = phi i80 [ %u.sroa.x, %if.x ],
[ %u.sroa.y, %if.y ],
[ %u.sroa.z, %if.z ]
and a dbg.value like this
call void @llvm.dbg.value(metadata i80 %u.sroa,
metadata !13,
metadata !DIExpression(DW_OP_LLVM_fragment, 0, 80))
The phi node is split into three 32-bit PHI nodes
%30:gr32 = PHI %11:gr32, %bb.4, %14:gr32, %bb.5, %27:gr32, %bb.8
%31:gr32 = PHI %12:gr32, %bb.4, %15:gr32, %bb.5, %28:gr32, %bb.8
%32:gr32 = PHI %13:gr32, %bb.4, %16:gr32, %bb.5, %29:gr32, %bb.8
but since the original value only is 80 bits we need to adjust the size
of the last fragment expression, and with this patch we get
DBG_VALUE debug-use %30:gr32, debug-use $noreg, !"u", !DIExpression(DW_OP_LLVM_fragment, 0, 32)
DBG_VALUE debug-use %31:gr32, debug-use $noreg, !"u", !DIExpression(DW_OP_LLVM_fragment, 32, 32)
DBG_VALUE debug-use %32:gr32, debug-use $noreg, !"u", !DIExpression(DW_OP_LLVM_fragment, 64, 16)
Reviewers: vsk, aprantl, mstorsjo
Reviewed By: aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46384
llvm-svn: 331464
Summary:
This is a follow up to rL331182. A PHI node can be split up into
several MIR PHI nodes when being selected. When there is a
dbg.value intrinsic that uses the result of such a PHI node we
need to select several DBG_VALUE instructions, with fragment
expressions, in order to do a correct selection.
Reviewers: rnk, aprantl, vsk
Reviewed By: vsk
Subscribers: mattd, llvm-commits, JDevlieghere, aprantl, gbedwell, rnk
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D46329
llvm-svn: 331337
LLVM always puts function definition DIEs at the top level, but under
some circumstances GCC does not (at least in this case with member
functions of a function-local type).
To ensure that doesn't appear as though the local type's member function
is unduly inlined within the outer function - ensure the inline
discovery DIE parent walk stops at the first DW_TAG_subprogram.
llvm-svn: 331291
This appears to have some issues associated with the file directive output
causing multiple global symbols with the name "file" to be emitted into a
startup section. I'm investigating more specific causes and working with the
original author.
This reverts commit r330271.
Also Revert "[DEBUGINFO, NVPTX] Add the test for the debug info of the local"
This reverts commit r330592 and the follow up of 330779 as the testcase is dependent upon r330271.
llvm-svn: 331237
Summary:
This patch will introduce copying of DBG_VALUE instructions
from an otherwise empty basic block to predecessor/successor
blocks in case the empty block is eliminated/bypassed. It
is currently only done in one identified situation in the
BranchFolding pass, before optimizing on empty block.
It can be seen as a light variant of the propagation done
by the LiveDebugValues pass, which unfortunately is executed
after the BranchFolding pass.
We only propagate (copy) DBG_VALUE instructions in a limited
number of situations:
a) If the empty BB is the only predecessor of a successor
we can copy the DBG_VALUE instruction to the beginning of
the successor (because the DBG_VALUE instruction is always
part of the flow between the blocks).
b) If the empty BB is the only successor of a predecessor
we can copy the DBG_VALUE instruction to the end of the
predecessor (because the DBG_VALUE instruction is always
part of the flow between the blocks). In this case we add
the DBG_VALUE just before the first terminator (assuming
that the terminators do not impact the DBG_VALUE).
A future solution, to handle more situations, could perhaps
be to run the LiveDebugValues pass before branch folding?
This fix is related to PR37234. It is expected to resolve
the problem seen, when applied together with the fix in
SelectionDAG from here: https://reviews.llvm.org/D46129
Reviewers: #debug-info, aprantl, rnk
Reviewed By: #debug-info, aprantl
Subscribers: ormris, gbedwell, llvm-commits
Differential Revision: https://reviews.llvm.org/D46184
llvm-svn: 331183
Summary:
When building the selection DAG at ISel all PHI nodes are
selected and lowered to Machine Instruction PHI nodes before
we start to create any SDNodes. So there are no SDNodes for
values produced by the PHI nodes.
In the past when selecting a dbg.value intrinsic that uses
the value produced by a PHI node we have been handling such
dbg.value intrinsics as "dangling debug info". I.e. we have
not created a SDDbgValue node directly, because there is
no existing SDNode for the PHI result, instead we deferred
the creationg of a SDDbgValue until we found the first use
of the PHI result.
The old solution had a couple of flaws. The position of the
selected DBG_VALUE instruction would end up quite late in a
basic block, and for example not directly after the PHI node
as in the LLVM IR input. And in case there were no use at all
in the basic block the dbg.value could be dropped completely.
This patch introduces a new VREG kind of SDDbgValue nodes.
It is similar to a SDNODE kind of node, but it refers directly
to a virtual register and not a SDNode. When we do selection
for a dbg.value that is using the result of a PHI node we
can do a lookup of the virtual register directly (as it already
is determined for the PHI node) and create a SDDbgValue node
immediately instead of delaying the selection until we find a
use.
This should fix a problem with losing debug info at ISel
as seen in PR37234 (https://bugs.llvm.org/show_bug.cgi?id=37234).
It does not resolve PR37234 completely, because the debug info
is dropped later on in the BranchFolder (see D46184).
Reviewers: #debug-info, aprantl
Reviewed By: #debug-info, aprantl
Subscribers: rnk, gbedwell, aprantl, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D46129
llvm-svn: 331182
For local variables the first DW_OP_deref is consumed by turning the
location kind into a memeory location, but that only makes sense for
values that are in a register to begin with, which cannot happen for
global variables that are attached to a symbol.
rdar://problem/39741860
This reapplies r330970 after fixing an uncovered bug in r331086 and
working around the situation caused by it.
llvm-svn: 331090
For local variables the first DW_OP_deref is consumed by turning the
location kind into a memeory location, but that only makes sense for
values that are in a register to begin with, which cannot happen for
global variables that are attached to a symbol.
rdar://problem/39741860
llvm-svn: 330970
Debug var, expr and loc were only supported for non-fixed stack objects.
This patch adds the following fields to the "fixedStack:" entries, and
renames the ones from "stack:" to:
* debug-info-variable
* debug-info-expression
* debug-info-location
Differential Revision: https://reviews.llvm.org/D46032
llvm-svn: 330859
Updated two more debug line related warnings to use WithColor. This was
necessary to ensure consistent output order of the warnings on Windows
for debug line tests.
Differential Revision: https://reviews.llvm.org/D45871
llvm-svn: 330440
On Windows, %llc_dwarf automatically adds -mtriple causing this test to
error. Changed %llc_dwarf to llc.
Differential Revision: https://reviews.llvm.org/D45869
llvm-svn: 330414
Summary:
Patch adds initial emission of the debug info for NVPTX target.
Currently, only .file and .loc directives are emitted, everything else is
commented out to not break the compilation of Cuda.
Reviewers: echristo, jlebar, tra, jholewinski
Subscribers: mgorny, aprantl, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D41827
llvm-svn: 330271
It seems llc crashes when targetting darwin with split-dwarf (pr37164).
This happens on all inputs, not just the one I added in the above
commit. Work around the issue by hardcoding the target triple to linux,
which is what all split-dwarf tests seem to be doing.
As I don't know of a way to specify the os part of the triple without
spelling out the architecture as well, I move the new test to the X86
folder.
llvm-svn: 330265
Summary:
Previously we crashed for the combination of the two features because we
tried to reference the dwo CU from the main object file. The fix
consists of two items:
- reference the skeleton CU from the name index (the consumer is
expected to use the skeleton CU to find the real data).
- use the main object file string pool for the strings in the index
Reviewers: JDevlieghere, aprantl, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45566
llvm-svn: 330249
Summary:
When sinking an instruction in InstCombine we now also sink
the DbgInfoIntrinsics that are using the sunken value.
Example)
When sinking the load in this input
bb.X:
%0 = load i64, i64* %start, align 4, !dbg !31
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
br label %for.body
we now also move the dbg.value, like this
bb.X:
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
%0 = load i64, i64* %start, align 4, !dbg !31
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br label %for.body
In the past we haven't moved the dbg.value so we got
bb.X:
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
%0 = load i64, i64* %start, align 4, !dbg !31
br label %for.body
So in the past we got a debug-use before the def of %0.
And that dbg.value was also on the path jumping to %for.end, for
which %0 never was defined.
CodeGenPrepare normally comes to rescue later (when not moving
the dbg.value), since it moves dbg.value instrinsics quite
brutally, without really analysing if it is correct to move
the intrinsic (see PR31878).
So at the moment this patch isn't expected to have much impact,
besides that it is moving the dbg.value already in opt, making
the IR look more sane directly.
This can be seen as a preparation to (hopefully) make it possible
to turn off CodeGenPrepare::placeDbgValues later as a solution
to PR31878.
I also adjusted test/DebugInfo/X86/sdagsplit-1.ll to make the
IR in the test case up-to-date with this behavior in InstCombine.
Reviewers: rnk, vsk, aprantl
Reviewed By: vsk, aprantl
Subscribers: mattd, JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D45425
llvm-svn: 330243
The DBI stream contains a list of module descriptors. At the
beginning of each descriptor is a structure representing the first
section contribution in the output file for that module. LLD
currently doesn't fill out this structure at all, but link.exe
does. So as a precursor to emitting this data in LLD, we first
need a way to dump it so that it can be checked.
This patch adds support for the dumping, and verifies via a test
that LLD emits bogus information.
llvm-svn: 330208
Apparently, DebugInfoFinder::processCompileUnit doesn't process all
of the possible kinds of DIImportedEntit'ies, e.g. DIGlobalVariable's.
Previously introduced `llvm_unreachable` is therefore incorrect.
Removing it here.
llvm-svn: 330167
When emitting CodeView debug information, compiler-generated thunk routines
should be emitted using S_THUNK32 symbols instead of S_GPROC32_ID symbols so
Visual Studio can properly step into the user code. This initial support only
handles standard thunk ordinals.
Differential Revision: https://reviews.llvm.org/D43838
llvm-svn: 330132
As demonstrated by the regression tests added in this patch, the
following cases are valid cases:
1. A Function with no DISubprogram attached, but various debug info
related to its instructions, coming, for instance, from an inlined
function, also defined somewhere else in the same module;
2. ... or coming exclusively from the functions inlined and eliminated
from the module entirely.
The ValueMap shared between CloneFunctionInto calls within CloneModule
needs to contain identity mappings for all of the DISubprogram's to
prevent them from being duplicated by MapMetadata / RemapInstruction
calls, this is achieved via DebugInfoFinder collecting all the
DISubprogram's. However, CloneFunctionInto was missing calls into
DebugInfoFinder for functions w/o DISubprogram's attached, but still
referring DISubprogram's from within (case 1). This patch fixes that.
The fix above, however, exposes another issue: if a module contains a
DISubprogram referenced only indirectly from other debug info
metadata, but not attached to any Function defined within the module
(case 2), cloning such a module causes a DICompileUnit duplication: it
will be moved in indirecty via a DISubprogram by DebugInfoFinder first
(because of the first bug fix described above), without being
self-mapped within the shared ValueMap, and then will be copied during
named metadata cloning. So this patch makes sure DebugInfoFinder
visits DICompileUnit's referenced from DISubprogram's as it goes w/o
re-processing llvm.dbg.cu list over and over again for every function
cloned, and makes sure that CloneFunctionInto self-maps
DICompileUnit's referenced from the entire function, not just its own
DISubprogram attached that may also be missing.
The most convenient way of tesing CloneModule I found is to rely on
CloneModule call from `opt -run-twice`, instead of writing tedious
unit tests. That feature has a couple of properties that makes it hard
to use for this purpose though:
1. CloneModule doesn't copy source filename, making `opt -run-twice`
report it as a difference.
2. `opt -run-twice` does the second run on the original module, not
its clone, making the result of cloning completely invisible in opt's
actual output with and without `-run-twice` both, which directly
contradicts `opt -run-twice`s own error message.
This patch fixes this as well.
Reviewed By: aprantl
Reviewers: loladiro, GorNishanov, espindola, echristo, dexonsmith
Subscribers: vsk, debug-info, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D45593
llvm-svn: 330069
This lifts a restriction on DILocation::getMergedLocation(), allowing it
to create merged locations for instructions other than calls.
Instruction::applyMergedLocation() now defaults to creating merged
locations for all instructions.
The default behavior of getMergedLocation() is unchanged: callers which
invoke it directly are unaffected.
This change will enable a follow-up Mem2Reg fix which improves crash
reporting.
Differential Revision: https://reviews.llvm.org/D45396
llvm-svn: 329955
Most importantly, we should not replace slashes with backslashes
because that would invalidate the path.
Differential Revision: https://reviews.llvm.org/D45473
llvm-svn: 329838
This is causing compilation timeouts on code with long sequences of
local values and calls (i.e. foo(1); foo(2); foo(3); ...). It turns out
that code coverage instrumentation is a great way to create sequences
like this, which how our users ran into the issue in practice.
Intel has a tool that detects these kinds of non-linear compile time
issues, and Andy Kaylor reported it as PR37010.
The current sinking code scans the whole basic block once per local
value sink, which happens before emitting each call. In theory, local
values should only be introduced to be used by instructions between the
current flush point and the last flush point, so we should only need to
scan those instructions.
llvm-svn: 329822
Summary:
This type is created on-demand and used as the base type for array
ranges. Since it is "special", its construction did not go through the
createTypeDIE function and so it was never inserted into the accelerator
table, although it clearly belongs there.
I add an explicit addAccelType call to insert it into the table.
During review, we also decided to rename the type to something more
unique to avoid confusion in case the user has own "sizetype" type. The
new name for the type size __ARRAY_SIZE_TYPE__.
Reviewers: JDevlieghere, aprantl, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45445
llvm-svn: 329705
Summary:
If an input DICompileUnit is completely empty (e.g., the result of
running "clang -g" on an empty file), we don't bother emitting an empty
DWARF CU. When we do that, we must make sure we don't also emit a DWARF v5
name index, as DWARF specifies that each index must reference at least
one compilation unit.
Reviewers: JDevlieghere, aprantl, dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45435
llvm-svn: 329575
- when tuning for SCE debugger (default for ps4 targets), we will not emit
the DW_AT_linkage_name, which this test needs. I explicitly set the
debugger tuning parameter to get the attribute always.
- darwin targets did not like the "section .text.startup" fragment of
the test. This is not actually needed for the test, so I remove it.
llvm-svn: 329555
Summary:
We were emitting accelerator entries for functions with no name, which
is contrary to the DWARF v5 spec: "All other (i.e., *not*
DW_TAG_namespace) debugging information entries without a DW_AT_name
attribute are excluded." Besides that, a name table entry with an empty
string as a key is fairly useless.
We can sometimes end up with functions which have a DW_AT_linkage_name but no
DW_AT_name. One such example is the global-constructor-initialization functions,
which C++ compilers synthesize for each compilation unit with global
constructors.
A very strict reading of the DWARF v5 spec would suggest that we should not even
emit the accelerator entry for the linkage name in this case, but I don't think
we should go that far.
I found this when running the dwarf verifier over llvm codebase compiled
with DWARF v5 accelerator tables.
Reviewers: JDevlieghere, aprantl, dblaikie
Subscribers: vleschuk, clayborg, echristo, probinson, llvm-commits
Differential Revision: https://reviews.llvm.org/D45367
llvm-svn: 329552
- MSVC was not OK with a static_assert referencing a non-static member
variable, even though it was just in a sizeof(expression). I move the
assert into the emit function, where it is probably more useful.
- Tests were failing in builds which did not have the X86 target
configured. Since this functionality is not target-specific, I have
removed the target specifiers from the .ll files.
llvm-svn: 329201
Summary:
This patch adds a DwarfAccelTableEmitter class, which generates an
accelerator table, as specified in DWARF v5 standard. At the moment it
only generates a DIE offset column and (if we are indexing more than one
compile unit) a CU column.
Indexing type units is not currently supported, as we don't even have
the ability to generate DWARF v5-compatible compile units.
The implementation is not data-source agnostic like the one generating
apple tables. This was not necessary as we currently only have one user
of this code, and without a second user it was not obvious to me how to
best abstract this. (The difference between these tables and the apple
ones is that they need a lot more metadata about the debug info they are
indexing).
The generation is triggered by the --accel-tables argument, which
supersedes the --dwarf-accel-tables arg -- the latter was a simple
on-off switch, but not we can choose between two kinds of accelerator
tables we can generate.
This is tested by parsing the generated tables with llvm-dwarfdump and
the DWARFVerifier, and I've also checked that GNU readelf is able to
make sense of the tables.
Differential Revision: https://reviews.llvm.org/D43286
llvm-svn: 329179
