Commit Graph

642 Commits

Author SHA1 Message Date
Chandler Carruth
363ac68374 [CallSite removal] Migrate all Alias Analysis APIs to use the newly
minted `CallBase` class instead of the `CallSite` wrapper.

This moves the largest interwoven collection of APIs that traffic in
`CallSite`s. While a handful of these could have been migrated with
a minorly more shallow migration by converting from a `CallSite` to
a `CallBase`, it hardly seemed worth it. Most of the APIs needed to
migrate together because of the complex interplay of AA APIs and the
fact that converting from a `CallBase` to a `CallSite` isn't free in its
current implementation.

Out of tree users of these APIs can fairly reliably migrate with some
combination of `.getInstruction()` on the `CallSite` instance and
casting the resulting pointer. The most generic form will look like `CS`
-> `cast_or_null<CallBase>(CS.getInstruction())` but in most cases there
is a more elegant migration. Hopefully, this migrates enough APIs for
users to fully move from `CallSite` to the base class. All of the
in-tree users were easily migrated in that fashion.

Thanks for the review from Saleem!

Differential Revision: https://reviews.llvm.org/D55641

llvm-svn: 350503
2019-01-07 05:42:51 +00:00
Florian Hahn
7902405c42 [ValueTracking] Fix a misuse of APInt in GetPointerBaseWithConstantOffset
GetPointerBaseWithConstantOffset include this code, where ByteOffset
and GEPOffset are both of type llvm::APInt :

  ByteOffset += GEPOffset.getSExtValue();

The problem with this line is that getSExtValue() returns an int64_t, but
the += matches an overload for uint64_t. The problem is that the resulting
APInt is no longer considered to be signed. That in turn causes assertion
failures later on if the relevant pointer type is > 64 bits in width and
the GEPOffset was negative.

Changing it to

  ByteOffset += GEPOffset.sextOrTrunc(ByteOffset.getBitWidth());

resolves the issue and explicitly performs the sign-extending
or truncation. Additionally, instead of asserting later if the result
is > 64 bits, it breaks out of the loop in that case.

See also
 https://reviews.llvm.org/D24729
 https://reviews.llvm.org/D24772

This commit must be merged after D38662 in order for the test to pass.

Patch by Michael Ferguson <mpfergu@gmail.com>.

Reviewers: reames, sanjoy, hfinkel

Reviewed By: hfinkel

Differential Revision: https://reviews.llvm.org/D38501

llvm-svn: 350395
2019-01-04 14:53:22 +00:00
Vedant Kumar
b264d69de7 [IR] Add Instruction::isLifetimeStartOrEnd, NFC
Instruction::isLifetimeStartOrEnd() checks whether an Instruction is an
llvm.lifetime.start or an llvm.lifetime.end intrinsic.

This was suggested as a cleanup in D55967.

Differential Revision: https://reviews.llvm.org/D56019

llvm-svn: 349964
2018-12-21 21:49:40 +00:00
Sanjay Patel
798c5982a0 [ValueTracking] remove unused parameters from helper functions; NFC
llvm-svn: 349641
2018-12-19 16:49:18 +00:00
Nikita Popov
687b92cd9c [ValueTracking] Support funnel shifts in computeKnownBits()
If the shift amount is known, we can determine the known bits of the
output based on the known bits of two inputs.

This is essentially the same functionality as implemented in D54869,
but for ValueTracking rather than InstCombine SimplifyDemandedBits.

Differential Revision: https://reviews.llvm.org/D55140

llvm-svn: 348091
2018-12-02 14:14:11 +00:00
Sanjay Patel
7d82d37854 [ValueTracking] add helper function for testing implied condition; NFCI
We were duplicating code around the existing isImpliedCondition() that
checks for a predecessor block/dominating condition, so make that a
wrapper call.

llvm-svn: 348088
2018-12-02 13:26:03 +00:00
Nikita Popov
cf596a8c26 [ValueTracking] Determine always-overflow condition for unsigned sub
Always-overflow was already determined for unsigned addition, but
not subtraction. This patch establishes parity.

This allows us to perform some additional simplifications for
signed saturating subtractions.

This change is part of https://reviews.llvm.org/D54534.

llvm-svn: 347771
2018-11-28 16:37:04 +00:00
Sanjay Patel
e7c94ef1de [ValueTracking] determine sign of 0.0 from select when matching min/max FP
In PR39475:
https://bugs.llvm.org/show_bug.cgi?id=39475
..we may fail to recognize/simplify fabs() in some cases because we do not 
canonicalize fcmp with a -0.0 operand.

Adding that canonicalization can cause regressions on min/max FP tests, so 
that's this patch: for the purpose of determining whether something is min/max, 
let the value returned by the select determine how we treat a 0.0 operand in the fcmp.

This patch doesn't actually change the -0.0 to +0.0. It just changes the analysis, so 
we don't fail to recognize equivalent min/max patterns that only differ in the 
signbit of 0.0.

Differential Revision: https://reviews.llvm.org/D54001

llvm-svn: 346097
2018-11-04 14:28:48 +00:00
Sanjay Patel
cac28b452e [ValueTracking] peek through 2-input shuffles in ComputeNumSignBits
This patch gives the IR ComputeNumSignBits the same functionality as the 
DAG version (the code is derived from the existing code).

This an extension of the single input shuffle analysis added with D53659.

Differential Revision: https://reviews.llvm.org/D53987

llvm-svn: 346071
2018-11-03 13:18:55 +00:00
Sanjay Patel
a68096c73e [ValueTracking] allow non-canonical shuffles when computing signbits
This possibility is noted in D53987 for a different case,
so we need to adjust the existing code.

llvm-svn: 345988
2018-11-02 15:51:47 +00:00
Sanjay Patel
cc9e401e3c [ValueTracking] peek through shuffles in ComputeNumSignBits (PR37549)
The motivating case is from PR37549:
https://bugs.llvm.org/show_bug.cgi?id=37549

The analysis improvement allows us to form a vector 'select' out of 
bitwise logic (the use of ComputeNumSignBits was added at rL345149).

The smaller test shows another InstCombine improvement - we use 
ComputeNumSignBits to add 'nsw' to shift-left. But the negative
test shows an example where we must not add 'nsw' - when the shuffle
mask contains undef elements.

Differential Revision: https://reviews.llvm.org/D53659

llvm-svn: 345429
2018-10-26 21:05:14 +00:00
Thomas Lively
c339250e12 [InstCombine] InstCombine and InstSimplify for minimum and maximum
Summary: Depends on D52765

Reviewers: aheejin, dschuff

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52766

llvm-svn: 344799
2018-10-19 19:01:26 +00:00
Thomas Lively
d47b5c7bed [ValueTracking] Allow select patterns to work on FP vectors
Summary:
This CL allows constant vectors of floats to be recognized as non-NaN
and non-zero in select patterns. This change makes
`matchSelectPattern` more powerful generally, but was motivated
specifically because I wanted fminnan and fmaxnan to be created for
vector versions of the scalar patterns they are created for.

Tested with check-all on all targets. A testcase in the WebAssembly
backend that tests the non-nan codepath is in an upcoming CL.

Reviewers: aheejin, dschuff

Subscribers: sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52324

llvm-svn: 343364
2018-09-28 21:36:43 +00:00
JF Bastien
73d8e4e531 Merge clang's isRepeatedBytePattern with LLVM's isBytewiseValue
Summary:
his code was in CGDecl.cpp and really belongs in LLVM's isBytewiseValue. Teach isBytewiseValue the tricks clang's isRepeatedBytePattern had, including merging undef properly, and recursing on more types.

clang part of this patch: D51752

Subscribers: dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D51751

llvm-svn: 342709
2018-09-21 05:17:42 +00:00
Max Kazantsev
3c284bde3f Re-enable "[NFC] Unify guards detection"
rL340921 has been reverted by rL340923 due to linkage dependency
from Transform/Utils to Analysis which is not allowed. In this patch
this has been fixed, a new utility function moved to Analysis.

Differential Revision: https://reviews.llvm.org/D51152

llvm-svn: 341014
2018-08-30 03:39:16 +00:00
Hans Wennborg
2c390c54f6 Revert r340921 "[NFC] Unify guards detection"
This broke the build, see e.g.

http://lab.llvm.org:8011/builders/clang-cmake-armv8-lnt/builds/4626/
http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/18647/
http://lab.llvm.org:8011/builders/clang-cmake-x86_64-avx2-linux/builds/5856/
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/22800/

> We have multiple places in code where we try to identify whether or not
> some instruction is a guard. This patch factors out this logic into a separate
> utility function which works uniformly in all places.
>
> Differential Revision: https://reviews.llvm.org/D51152
> Reviewed By: fedor.sergeev

llvm-svn: 340923
2018-08-29 12:21:32 +00:00
Max Kazantsev
1dafaa87d9 [NFC] Unify guards detection
We have multiple places in code where we try to identify whether or not
some instruction is a guard. This patch factors out this logic into a separate
utility function which works uniformly in all places.

Differential Revision: https://reviews.llvm.org/D51152
Reviewed By: fedor.sergeev

llvm-svn: 340921
2018-08-29 11:37:34 +00:00
Craig Topper
dfa176e813 [ValueTracking] Fix assert message and add test case for r340546 and PR38677.
The bug was already fixed. This just adds a test case for it.

llvm-svn: 340556
2018-08-23 17:45:53 +00:00
Craig Topper
15f8692381 [ValueTracking] Fix an assert from r340480.
We need to allow ConstantExpr Selects in addition to SelectInst.

I'll try to put together a test case, but I wanted to fix the issues being reported.

Fixes PR38677

llvm-svn: 340546
2018-08-23 17:15:02 +00:00
Craig Topper
bec15b6516 [ValueTracking] Teach computeNumSignBits to understand min/max clamp patterns with constant/splat values
If we have a min/max pair we can do a better job of counting sign bits if we look at them together. This is similar to what is done in the SelectionDAG version of computeNumSignBits for ISD::SMAX/SMIN.

Differential Revision: https://reviews.llvm.org/D51112

llvm-svn: 340480
2018-08-22 23:27:50 +00:00
Matt Arsenault
450fcc77a7 ValueTracking: Handle more instructions in isKnownNeverNaN
llvm-svn: 340187
2018-08-20 16:51:00 +00:00
Florian Hahn
19f9e32f07 [InstrSimplify,NewGVN] Add option to ignore additional instr info when simplifying.
NewGVN uses InstructionSimplify for simplifications of leaders of
congruence classes. It is not guaranteed that the metadata or other
flags/keywords (like nsw or exact) of the leader is available for all members
in a congruence class, so we cannot use it for simplification.

This patch adds a InstrInfoQuery struct with a boolean field
UseInstrInfo (which defaults to true to keep the current behavior as
default) and a set of helper methods to get metadata/keywords for a
given instruction, if UseInstrInfo is true. The whole thing might need a
better name, to avoid confusion with TargetInstrInfo but I am not sure
what a better name would be.

The current patch threads through InstrInfoQuery to the required
places, which is messier then it would need to be, if
InstructionSimplify and ValueTracking would share the same Query struct.

The reason I added it as a separate struct is that it can be shared
between InstructionSimplify and ValueTracking's query objects. Also,
some places do not need a full query object, just the InstrInfoQuery.

It also updates some interfaces that do not take a Query object, but a
set of optional parameters to take an additional boolean UseInstrInfo.

See https://bugs.llvm.org/show_bug.cgi?id=37540.

Reviewers: dberlin, davide, efriedma, sebpop, hiraditya

Reviewed By: hiraditya

Differential Revision: https://reviews.llvm.org/D47143

llvm-svn: 340031
2018-08-17 14:39:04 +00:00
Matt Arsenault
d54b7f0592 ValueTracking: Start enhancing isKnownNeverNaN
llvm-svn: 339399
2018-08-09 22:40:08 +00:00
Matt Arsenault
56b31d8d75 ValueTracking: Handle canonicalize in CannotBeNegativeZero
Also fix apparently missing test coverage for any of the
handling here.

llvm-svn: 339023
2018-08-06 15:16:26 +00:00
Max Kazantsev
2dbbd64cb7 Re-enable "[ValueTracking] Teach isKnownNonNullFromDominatingCondition about AND"
The patch was reverted because of bug detected by sanitizer. The bug is fixed,
respective tests added.

Differential Revision: https://reviews.llvm.org/D50172

llvm-svn: 339005
2018-08-06 11:14:18 +00:00
Max Kazantsev
3271f379a9 Revert rL338990 to see if it causes sanitizer failures
Multiple failues reported by sanitizer-x86_64-linux, seem to be caused by this
patch. Reverting to see if they sustain without it.

Differential Revision: https://reviews.llvm.org/D50172

llvm-svn: 338994
2018-08-06 08:10:28 +00:00
Max Kazantsev
34b0666be9 [ValueTracking] Teach isKnownNonNullFromDominatingCondition about AND
`isKnownNonNullFromDominatingCondition` is able to prove non-null basing on `br` or `guard`
by `%p != null` condition, but is unable to do so basing on `(%p != null) && %other_cond`.
This patch allows it to do so.

Differential Revision: https://reviews.llvm.org/D50172
Reviewed By: reames

llvm-svn: 338990
2018-08-06 06:11:36 +00:00
Sanjay Patel
f9a0d593e9 [ValueTracking] fix maxnum miscompile for cannotBeOrderedLessThanZero (PR37776)
This adds the NAN checks suggested in PR37776:
https://bugs.llvm.org/show_bug.cgi?id=37776

If both operands to maxnum are NAN, that should get constant folded, so we don't 
have to handle that case. This is the same assumption as other FP ops in this
function. Returning 'false' is always conservatively correct.

Copying from the bug report:

Currently, we have this for "when is cannotBeOrderedLessThanZero 
(mustBePositiveOrNaN) true for maxnum":
               L
        -------------------
        | Pos | Neg | NaN |
   ------------------------
   |Pos |  x  |  x  |  x  |
   ------------------------
 R |Neg |  x  |     |  x  |
   ------------------------
   |NaN |  x  |  x  |  x  |
   ------------------------


The cases with (Neg & NaN) are wrong. We should have:

                L
        -------------------
        | Pos | Neg | NaN |
   ------------------------
   |Pos |  x  |  x  |  x  |
   ------------------------
 R |Neg |  x  |     |     |
   ------------------------
   |NaN |  x  |     |  x  |
   ------------------------

Differential Revision: https://reviews.llvm.org/D50081

llvm-svn: 338716
2018-08-02 13:46:20 +00:00
Fangrui Song
f78650a8de Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h}

llvm-svn: 338293
2018-07-30 19:41:25 +00:00
Stanislav Mekhanoshin
b8269a9589 Fix llvm::ComputeNumSignBits with some operations and llvm.assume
Currently ComputeNumSignBits does early exit while processing some
of the operations (add, sub, mul, and select). This prevents the
function from using AssumptionCacheTracker if passed.

Differential Revision: https://reviews.llvm.org/D49759

llvm-svn: 337936
2018-07-25 16:39:24 +00:00
Chen Zheng
69bb064539 [InstrSimplify] fold sdiv if two operands are negated and non-overflow
Differential Revision: https://reviews.llvm.org/D49382

llvm-svn: 337642
2018-07-21 12:27:54 +00:00
Chen Zheng
ccc8422464 [InstCombine] add more SPFofSPF folding
Differential Revision: https://reviews.llvm.org/D49238

llvm-svn: 337143
2018-07-16 02:23:00 +00:00
Fangrui Song
9bb6c392e3 [InstCombine] Simplify isKnownNegation
llvm-svn: 336957
2018-07-12 22:56:23 +00:00
Chen Zheng
fdf13ef342 [InstSimplify] simplify add instruction if two operands are negative
Differential Revision: https://reviews.llvm.org/D49216

llvm-svn: 336881
2018-07-12 03:06:04 +00:00
Manoj Gupta
77eeac3d9e llvm: Add support for "-fno-delete-null-pointer-checks"
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613
2018-07-09 22:27:23 +00:00
Vedant Kumar
b3091da3af Use Type::isIntOrPtrTy where possible, NFC
It's a bit neater to write T.isIntOrPtrTy() over `T.isIntegerTy() ||
T.isPointerTy()`.

I used Python's re.sub with this regex to update users:

  r'([\w.\->()]+)isIntegerTy\(\)\s*\|\|\s*\1isPointerTy\(\)'

llvm-svn: 336462
2018-07-06 20:17:42 +00:00
Sanjay Patel
284ba0c18f [ValueTracking] allow undef elements when matching vector abs
llvm-svn: 336111
2018-07-02 14:43:40 +00:00
Piotr Padlewski
5b3db45e8f Implement strip.invariant.group
Summary:
This patch introduce new intrinsic -
strip.invariant.group that was described in the
RFC: Devirtualization v2

Reviewers: rsmith, hfinkel, nlopes, sanjoy, amharc, kuhar

Subscribers: arsenm, nhaehnle, JDevlieghere, hiraditya, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47103

Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 336073
2018-07-02 04:49:30 +00:00
John Brawn
c5a6392be3 [ValueTracking] Match select abs pattern when there's an sext involved
When checking a select to see if it matches an abs, allow the true/false values
to be a sign-extension of the comparison value instead of requiring that they're
directly the comparison value, as all the comparison cares about is the sign of
the value.

This fixes a regression due to r333702, where we were no longer generating ctlz
due to isKnownNonNegative failing to match such a pattern.

Differential Revision: https://reviews.llvm.org/D47631

llvm-svn: 333927
2018-06-04 16:53:57 +00:00
Karl-Johan Karlsson
ebaaa2ddae [ValueTracking] Fix endless recursion in isKnownNonZero()
Summary:
The isKnownNonZero() function have checks that abort the recursion when
it reaches the specified max depth. However one of the recursive calls
was placed before the max depth check was done, resulting in a endless
recursion that eventually triggered a segmentation fault.

Fixed the problem by moving the max depth check above the first
recursive call.

Reviewers: Prazek, nlopes, spatel, craig.topper, hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, bjope, llvm-commits

Differential Revision: https://reviews.llvm.org/D47531

llvm-svn: 333557
2018-05-30 15:56:46 +00:00
Craig Topper
8f77dcadff Recommit r333226 "[ValueTracking] Teach computeKnownBits that the result of an absolute value pattern that uses nsw flag is always positive."
Libfuzzer tests have been fixed to prevent being optimized.

Original commit message:

If the nsw flag is used in the absolute value then it is undefined for INT_MIN. For all other value it will produce a positive number. So we can assume the result is positive.

This breaks some InstCombine abs/nabs combining tests because we simplify the second compare from known bits rather than as the whole pattern. Looks like we can probably fix it by adding a neg+abs/nabs combine to just swap the select operands. N

Differential Revision: https://reviews.llvm.org/D47041

llvm-svn: 333300
2018-05-25 19:18:09 +00:00
Craig Topper
8174281b93 Revert r333226 "[ValueTracking] Teach computeKnownBits that the result of an absolute value pattern that uses nsw flag is always positive."
This breaks some libFuzzer tests. http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer/builds/15589/steps/check-fuzzer/logs/stdio

Reverting to investigate

llvm-svn: 333253
2018-05-25 04:01:56 +00:00
Craig Topper
49f23fe349 [ValueTracking] Teach computeKnownBits that the result of an absolute value pattern that uses nsw flag is always positive.
If the nsw flag is used in the absolute value then it is undefined for INT_MIN. For all other value it will produce a positive number. So we can assume the result is positive.

This breaks some InstCombine abs/nabs combining tests because we simplify the second compare from known bits rather than as the whole pattern. Looks like we can probably fix it by adding a neg+abs/nabs combine to just swap the select operands. Need to check alive to make sure there are no corner cases.

Differential Revision: https://reviews.llvm.org/D47041

llvm-svn: 333226
2018-05-24 21:22:51 +00:00
Piotr Padlewski
d6f7346a4b Fix aliasing of launder.invariant.group
Summary:
Patch for capture tracking broke
bootstrap of clang with -fstict-vtable-pointers
which resulted in debbugging nightmare. It was fixed
https://reviews.llvm.org/D46900 but as it turned
out, there were other parts like inliner (computing of
noalias metadata) that I found after bootstraping with enabled
assertions.

Reviewers: hfinkel, rsmith, chandlerc, amharc, kuhar

Subscribers: JDevlieghere, eraman, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D47088

llvm-svn: 333070
2018-05-23 09:16:44 +00:00
David Bolvansky
1f343fa0e0 [InstCombine] Remove calloc transformations
Summary: Previous patch does not care if a value is changed between calloc and strlen. This needs to be removed from InstCombine and maybe moved to DSE later after some rework.

Reviewers: efriedma

Reviewed By: efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47218

llvm-svn: 333022
2018-05-22 20:27:36 +00:00
David Bolvansky
41f4b64ee1 [InstCombine] Calloc-ed strings optimizations
Summary:
Example cases:
strlen(calloc(...)) -> 0

Reviewers: efriedma, bkramer

Reviewed By: bkramer

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47059

llvm-svn: 332990
2018-05-22 15:41:23 +00:00
Craig Topper
f14e62c9a5 [EarlyCSE] Improve EarlyCSE of some absolute value cases.
Change matchSelectPattern to return X and -X for ABS/NABS in a well defined order. Adjust EarlyCSE to account for this. Ensure the SPF result is some kind of min/max and not abs/nabs in one place in InstCombine that made me nervous.

Prevously we returned the two operands of the compare part of the abs pattern. The RHS is always going to be a 0i, 1 or -1 constant. This isn't a very meaningful thing to return for any one. There's also some freedom in the abs pattern as to what happens when the value is equal to 0. This freedom led to early cse failing to match when different constants were used in otherwise equivalent operations. By returning the input and its negation in a defined order we can ensure an exact match. This also makes sure both patterns use the exact same subtract instruction for the negation. I believe CSE should evebntually make this happen and properly merge the nsw/nuw flags. But I'm not familiar with CSE and what order it does things in so it seemed like it might be good to really enforce that they were the same.

Differential Revision: https://reviews.llvm.org/D47037

llvm-svn: 332865
2018-05-21 18:42:42 +00:00
Piotr Padlewski
5642a42442 Propagate nonnull and dereferenceable throught launder
Summary:
invariant.group.launder should not stop propagation
of nonnull and dereferenceable, because e.g. we would not be
able to hoist loads speculatively.

Reviewers: rsmith, amharc, kuhar, xbolva00, hfinkel

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D46972

llvm-svn: 332788
2018-05-18 23:54:33 +00:00
Omer Paparo Bivas
fbb83deef7 [InstCombine] Moving overflow computation logic from InstCombine to ValueTracking; NFC
Differential Revision: https://reviews.llvm.org/D46704

Change-Id: Ifabcbe431a2169743b3cc310f2a34fd706f13f02
llvm-svn: 332026
2018-05-10 19:46:19 +00:00
Shiva Chen
2c864551df [DebugInfo] Add DILabel metadata and intrinsic llvm.dbg.label.
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
2018-05-09 02:40:45 +00:00