Commit Graph

810 Commits

Author SHA1 Message Date
Adrian Prantl 99ba97726a Fix a crash when emitting debug info for multi-reg function arguments
by reusing more of the existing machinery

This is a follow-up to r312169.
Thanks to Björn Pettersson for the testcase!

llvm-svn: 312773
2017-09-08 02:31:37 +00:00
Sam McCall f71bb198ed Revert "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
This crashes on boringSSL on PPC (will send reduced testcase)

This reverts commit r312328.

llvm-svn: 312490
2017-09-04 15:47:00 +00:00
George Rimar 2f95c8bccb [DebugInfo] - Fix for lld DWARF parsing of base address selection entries in range lists.
It solves issue of wrong section index evaluating for ranges when
base address is used.

Based on David Blaikie's patch D36097.

Differential revision: https://reviews.llvm.org/D37214

llvm-svn: 312477
2017-09-04 10:30:39 +00:00
Geoff Berry 65528f2991 Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues addressed since original review:
- Moved removal of dead instructions found by
  LiveIntervals::shrinkToUses() outside of loop iterating over
  instructions to avoid instructions being deleted while pointed to by
  iterator.
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 312328
2017-09-01 14:27:20 +00:00
Hans Wennborg 24775a0a6c Revert r312154 "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!")

> Issues identified by buildbots addressed since original review:
> - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
> - The pass no longer forwards COPYs to physical register uses, since
>   doing so can break code that implicitly relies on the physical
>   register number of the use.
> - The pass no longer forwards COPYs to undef uses, since doing so
>   can break the machine verifier by creating LiveRanges that don't
>   end on a use (since the undef operand is not considered a use).
>
>   [MachineCopyPropagation] Extend pass to do COPY source forwarding
>
>   This change extends MachineCopyPropagation to do COPY source forwarding.
>
>   This change also extends the MachineCopyPropagation pass to be able to
>   be run during register allocation, after physical registers have been
>   assigned, but before the virtual registers have been re-written, which
>   allows it to remove virtual register COPY LiveIntervals that become dead
>   through the forwarding of all of their uses.

llvm-svn: 312178
2017-08-30 22:11:37 +00:00
Geoff Berry feffb0c8af Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues identified by buildbots addressed since original review:
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 312154
2017-08-30 18:41:07 +00:00
Adrian Prantl 05782218ab Canonicalize the representation of empty an expression in DIGlobalVariableExpression
This change simplifies code that has to deal with
DIGlobalVariableExpression and mirrors how we treat DIExpressions in
debug info intrinsics. Before this change there were two ways of
representing empty expressions on globals, a nullptr and an empty
!DIExpression().

If someone needs to upgrade out-of-tree testcases:
  perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll>
will catch 95%.

llvm-svn: 312144
2017-08-30 18:06:51 +00:00
Reid Kleckner 2297fc89b4 Fix the dwarfdump test so that it passes in its new location
llvm-svn: 312051
2017-08-29 22:25:16 +00:00
Reid Kleckner 14469db602 Move dwarfdump test to DebugInfo/X86 now that it looks for x86 register names
Otherwise this test will fail on bots (like the hexagon bot) that don't
enable the x86 backend.

llvm-svn: 312050
2017-08-29 22:16:11 +00:00
Reid Kleckner a058736c9c [dwarfdump] Pretty print location expressions and location lists
Summary:
Based on Fred's patch here: https://reviews.llvm.org/D6771

I can't seem to commandeer the old review, so I'm creating a new one.

With that change the locations exrpessions are pretty printed inline in the
DIE tree. The output looks like this for debug_loc entries:

    DW_AT_location [DW_FORM_data4]        (0x00000000
       0x0000000000000001 - 0x000000000000000b: DW_OP_consts +3
       0x000000000000000b - 0x0000000000000012: DW_OP_consts +7
       0x0000000000000012 - 0x000000000000001b: DW_OP_reg0 RAX, DW_OP_piece 0x4
       0x000000000000001b - 0x0000000000000024: DW_OP_breg5 RDI+0)

And like this for debug_loc.dwo entries:
    DW_AT_location [DW_FORM_sec_offset]   (0x00000000
      Addr idx 2 (w/ length 190): DW_OP_consts +0, DW_OP_stack_value
      Addr idx 3 (w/ length 23): DW_OP_reg0 RAX, DW_OP_piece 0x4)

Simple locations without ranges are printed inline:

   DW_AT_location [DW_FORM_block1]       (DW_OP_reg4 RSI, DW_OP_piece 0x4, DW_OP_bit_piece 0x20 0x0)

The debug_loc(.dwo) dumping in changed accordingly to factor the code.

Reviewers: dblaikie, aprantl, friss

Subscribers: mgorny, javed.absar, hiraditya, llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D37123

llvm-svn: 312042
2017-08-29 21:41:21 +00:00
Reid Kleckner 6d353348e5 Parse and print DIExpressions inline to ease IR and MIR testing
Summary:
Most DIExpressions are empty or very simple. When they are complex, they
tend to be unique, so checking them inline is reasonable.

This also avoids the need for CodeGen passes to append to the
llvm.dbg.mir named md node.

See also PR22780, for making DIExpression not be an MDNode.

Reviewers: aprantl, dexonsmith, dblaikie

Subscribers: qcolombet, javed.absar, eraman, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D37075

llvm-svn: 311594
2017-08-23 20:31:27 +00:00
Adrian Prantl 2116dd360a Filter out non-constant DIGlobalVariableExpressions reachable via the CU
They won't affect the DWARF output, but they will mess with the
sorting of the fragments. This fixes the crash reported in PR34159.

https://bugs.llvm.org/show_bug.cgi?id=34159

llvm-svn: 311217
2017-08-19 01:15:06 +00:00
Jonas Devlieghere e101b07a1d [Debug info] Transfer DI to fragment expressions for split integer values.
This patch teaches the SDag type legalizer how to split up debug info for
integer values that are split into a hi and lo part.

(re-commit)

Differential Revision: https://reviews.llvm.org/D36805

llvm-svn: 311181
2017-08-18 18:07:00 +00:00
Jonas Devlieghere 30756da212 Revert "[Debug info] Transfer DI to fragment expressions for split integer values."
This reverts commit r311102.

llvm-svn: 311111
2017-08-17 17:58:33 +00:00
Jonas Devlieghere 622fedc001 [Debug info] Transfer DI to fragment expressions for split integer values.
This patch teaches the SDag type legalizer how to split up debug info for
integer values that are split into a hi and lo part.

Differential Revision: https://reviews.llvm.org/D36805

llvm-svn: 311102
2017-08-17 17:06:48 +00:00
Kuba Mracek 17ee427ef3 [llvm] Get rid of "%T" expansions
The %T lit expansion expands to a common directory shared between all the tests in the same directory, which is unexpected and unintuitive, and more importantly, it's been a source of subtle race conditions and flaky tests. In https://reviews.llvm.org/D35396, it was agreed that it would be best to simply ban %T and only keep %t, which is unique to each test. When a test needs a temporary directory, it can just create one using mkdir %t.

This patch removes %T in llvm.

Differential Revision: https://reviews.llvm.org/D36495

llvm-svn: 310953
2017-08-15 20:29:24 +00:00
George Rimar 6957ab5b7b [llvm-dwarfdump] - Print section name and index when dumping .debug_info ranges
Teaches llvm-dwarfdump to print section index and name of range
when it dumps .debug_info.

Differential revision: https://reviews.llvm.org/D36313

llvm-svn: 310915
2017-08-15 12:32:54 +00:00
Robert Lougher 10f740df4d [LiveDebugVariables] Use lexical scope to trim debug value live intervals
The debug value live intervals computed by Live Debug Variables may extend
beyond the range of the debug location's lexical scope. In this case,
splitting of an interval can result in an interval outside of the scope being
created, causing extra unnecessary DBG_VALUEs to be emitted. To prevent this,
trim the intervals to the lexical scope.

This resolves PR33730.

Reviewers: aprantl

Differential Revision: https://reviews.llvm.org/D35953

llvm-svn: 309933
2017-08-03 11:54:02 +00:00
Adrian Prantl 032d2381bf Remove PrologEpilogInserter's usage of DBG_VALUE's offset field
In the last half-dozen commits to LLVM I removed code that became dead
after removing the offset parameter from llvm.dbg.value gradually
proceeding from IR towards the backend. Before I can move on to
DwarfDebug and friends there is one last side-called offset I need to
remove:  This patch modifies PrologEpilogInserter's use of the
DBG_VALUE's offset argument to use a DIExpression instead. Because the
PrologEpilogInserter runs at the Machine level I had to play a little
trick with a named llvm.dbg.mir node to get the DIExpressions to print
in MIR dumps (which print the llvm::Module followed by the
MachineFunction dump).

I also had to add rudimentary DwarfExpression support to CodeView and
as a side-effect also fixed a bug (CodeViewDebug::collectVariableInfo
was supposed to give up on variables with complex DIExpressions, but
would fail to do so for fragments, which are also modeled as
DIExpressions).

With this last holdover removed we will have only one canonical way of
representing offsets to debug locations which will simplify the code
in DwarfDebug (and future versions of CodeViewDebug once it starts
handling more complex expressions) and make it easier to reason about.

This patch is NFC-ish: All test case changes are for assembler
comments and the binary output does not change.

rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D36125

llvm-svn: 309751
2017-08-01 21:45:24 +00:00
Reid Kleckner 29c675247d [DebugInfo] Don't turn dbg.declare into DBG_VALUE for static allocas
Summary:
We already have information about static alloca stack locations in our
side table. Emitting instructions for them is inefficient, and it only
happens when the address of the alloca has been materialized within the
current block, which isn't often.

Reviewers: aprantl, probinson, dblaikie

Subscribers: jfb, dschuff, sbc100, jgravelle-google, hiraditya, llvm-commits, aheejin

Differential Revision: https://reviews.llvm.org/D36117

llvm-svn: 309729
2017-08-01 19:45:09 +00:00
David Blaikie 038e28a5a7 DebugInfo: Put range base specifier entry functionality behind a flag
Chromium's gold build seems to have trouble with this (gold produces
errors) - not sure if it's gold that's not coping with the valid
representation, or a bug in the implementation in LLVM, etc.

llvm-svn: 309630
2017-07-31 21:48:42 +00:00
Adrian Prantl 56619fa7e9 Debug Info: Also check the DWARF output in assembler-only test cases
This will prevent me from introducing a regression in my next commit.

llvm-svn: 309623
2017-07-31 20:48:52 +00:00
David Blaikie 4dd663752d DebugInfo: Fix r309526, ensure resetting base address selection entries are used
Missed the resetting base address selections when going from a base
address version to zero base address for non-base-addressed entries.

llvm-svn: 309529
2017-07-31 00:18:24 +00:00
David Blaikie 89c81a0b91 DebugInfo: Use base address selection entries in debug_ranges to reduce relocations
(from comments in the test)
Group ranges in a range list that apply to the same section and use a base
address selection entry to reduce the number of relocations to one reloc per
section per range list. DWARF5 debug_rnglist will be more efficient than this
in terms of relocations, but it's still better than one reloc per entry in a
range list.

This is an object/executable size tradeoff - shrinking objects, but growing
the linked executable. In one large binary tested, total object size (not just
debug info) shrank by 16%, entirely relocation entries. Linked executable
grew by 4%. This was with compressed debug info in the objects, uncompressed
in the linked executable. Without compression in the objects, the win would be
smaller (the growth of debug_ranges itself would be more significant).

llvm-svn: 309526
2017-07-30 22:10:00 +00:00
Adrian Prantl abe04759a6 Remove the obsolete offset parameter from @llvm.dbg.value
There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.

rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951

llvm-svn: 309426
2017-07-28 20:21:02 +00:00
Adrian Prantl be66271f04 Debug Info: Support fragmented variables in the MMI side table
This reapplies commit r309034 with a bugfix+test for inlined variables.

llvm-svn: 309057
2017-07-25 23:32:59 +00:00
Adrian Prantl b6d5faf2ea Revert "Debug Info: Support fragmented variables in the MMI side table"
This reverts commit r309034 because of a sanitizer issue.

llvm-svn: 309035
2017-07-25 21:50:45 +00:00
Adrian Prantl 3d1ab0cd1e Debug Info: Support fragmented variables in the MMI side table
<rdar://problem/17816343>

llvm-svn: 309034
2017-07-25 21:29:22 +00:00
Adrian Prantl 65e7ca995d Debug Info: Don't strip clang module skeleton CUs.
This corrects a (hopefully :-) accidental side-effect of r304020.

rdar://problem/33442618

llvm-svn: 308708
2017-07-21 01:24:05 +00:00
Adrian Prantl d63bfd218b Debug Info: Add a file: field to DIImportedEntity.
DIImportedEntity has a line number, but not a file field. To determine
the decl_line/decl_file we combine the line number from the
DIImportedEntity with the file from the DIImportedEntity's scope. This
does not work correctly when the parent scope is a DINamespace or a
DIModule, both of which do not have a source file.

This patch adds a file field to DIImportedEntity to unambiguously
identify the source location of the using/import declaration.  Most
testcase updates are mechanical, the interesting one is the removal of
the FIXME in test/DebugInfo/Generic/namespace.ll.

This fixes PR33822. See https://bugs.llvm.org/show_bug.cgi?id=33822
for more context.

<rdar://problem/33357889>
https://bugs.llvm.org/show_bug.cgi?id=33822

Differential Revision: https://reviews.llvm.org/D35583

llvm-svn: 308398
2017-07-19 00:09:54 +00:00
Reid Kleckner 8d8888ff42 [codeview] Change readobj symbol dumping format
Avoid duplicating DictScope with hand-written names everywhere.  Print
the S_-prefixed symbol kind for every record. This should make it easier
to search for certain kinds of records when debugging PDB linking.

llvm-svn: 307732
2017-07-11 23:41:41 +00:00
Adrian Prantl 160a97d2e7 Move testcase into the target-appropriate subdirectory.
llvm-svn: 305602
2017-06-16 23:02:05 +00:00
Adrian Prantl 274bcbc139 Improve the accuracy of variable ranges .debug_loc location lists.
For the following motivating example
  bool c();
  void f();
  bool start() {
    bool result = c();
    if (!c()) {
      result = false;
      goto exit;
    }
    f();
    result = true;
  exit:
    return result;
  }

we would previously generate a single DW_AT_const_value(1) because
only the DBG_VALUE in the second-to-last basic block survived
codegen. This patch improves the heuristic used to determine when a
DBG_VALUE is available at the beginning of its variable's enclosing
lexical scope:

- Stop giving singular constants blanket permission to take over the
  entire scope. There is still a special case for constants in the
  function prologue that we also miight want to retire later.

- Use the lexical scope information to determine available-at-entry
  instead of proximity to the function prologue.

After this patch we generate a location list with a more accurate
narrower availability for the constant true value. As a pleasant side
effect, we also generate inline locations instead of location lists
where a loacation covers the entire range of the enclosing lexical
scope.

Measured on compiling llc with four targets this doesn't have an
effect on compile time and reduces the size of the debug info for llc
by ~600K.

rdar://problem/30286912

llvm-svn: 305599
2017-06-16 22:40:04 +00:00
Florian Hahn ffc498dfcc Align definition of DW_OP_plus with DWARF spec [3/3]
Summary:
This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things.
 
The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack.
 
This is done in three stages:
• The first patch (LLVM) adds support for DW_OP_plus_uconst.
• The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst.
• The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions.

Patch by Sander de Smalen.

Reviewers: echristo, pcc, aprantl

Reviewed By: aprantl

Subscribers: fhahn, javed.absar, aprantl, llvm-commits

Differential Revision: https://reviews.llvm.org/D33894

llvm-svn: 305386
2017-06-14 13:14:38 +00:00
Adrian Prantl 234b0e2198 Use a fixed target triple to s to appease windows bots
llvm-svn: 305252
2017-06-12 23:47:27 +00:00
Mehdi Amini 96ab48f9da DebugInfo: Include .dwo file name when hashing multiple CUs in a single file
This is really a workaround for ThinLTO in particular - since it can
import partial CUs that may end up looking very similar/the same as
the same partial import in another ThinLTO compile.

An alternative fix would be to change the DICompileUnit metadata to
include a "primary file" or the like - and when importing for ThinLTO
set the primary file to the name of the DICompileUnit that is being
imported into. This involves changing the schema and would reduce the
excessive uniqueness in the hash that this change creates - allowing
diagnosing of more duplicate CUs than will be caught with this change.

But duplicate CUs can still be caught in non-ThinLTO builds & are mostly
a nuisance rather than a particularly deliberate/effective tool for
finding broken code. (arguably the hash could always include the dwo
file and nothing in fission would break, I think..)

Reapply of r304119 after adding a triple to the test and moving it
to the X86 directory.

llvm-svn: 304130
2017-05-29 06:32:34 +00:00
Mehdi Amini 4181205563 DebugInfo: Omit an empty CU when a subprogram was moved into its use
When the only use of a CU is for a subprogram that's only emitted into
the using CU (to avoid cross-CU references in DWO files), avoid creating
that CU at all.

Reapply of r304111 after adding a triple to the test and moving it
to the X86 directory.

llvm-svn: 304129
2017-05-29 06:25:30 +00:00
David Blaikie 07963bd1d1 DebugInfo: Do not emit empty CUs
Consistent with GCC and addresses a shortcoming with ThinLTO where many
imported CUs may end up being empty (because the functions imported from
them either ended up not being used (and were then discarded, since
they're imported as available_externally) or optimized away entirely).

Test cases previously testing empty CUs (either intentionally, or
because they didn't need anything more complicated) had a trivial 'int'
or similar basic type added to their retained types list.

This is a first order approximation - a deeper implementation could do
things like:

1) Be more lazy about construction of the CU - for example if two CUs
containing a single identical retained type are linked together, with
this change one of the two CUs will be produced but empty (since a
duplicate type won't be produced).

2) Go further and invert all the CU links the same way the subprogram
link is inverted - keep named CU lists of retained types, macros, etc,
and have those link back to the CU. Then if they're emitted, the CU is
emitted, but never otherwise - this would allow the metadata itself to
be dropped earlier too, though it seems unlikely that's an important
optimization as there shouldn't be many CUs relative to the number of
other entities.

llvm-svn: 304020
2017-05-26 18:52:56 +00:00
Adrian Prantl f062192632 Fix SelectionDAGBuilder::getDbgValue to not expect DW_OP_deref on FI vars
This fixes an oversight in r300522, which changed alloca
dbg.values to no longer emit a DW_OP_deref.

The array.ll testcase was regenerated from source.

Fixes PR33166:
https://bugs.llvm.org/show_bug.cgi?id=33166

llvm-svn: 303897
2017-05-25 18:54:10 +00:00
David Blaikie b3cee2fb42 DebugInfo: Produce debug_{gnu_}pub{names,types} entries when explicitly requested, even in -gmlt or when empty
Turns out gold doesn't use the DW_AT_GNU_pubnames to decide whether to
parse the rest of the DIEs when building gdb-index. This causes gold to
trip over LLVM's output when there are DW_FORM_ref_addr present.

Gold does use the presence of a debug_gnu_pub{names,types} entry for the
CU to skip parsing the debug_info portion, so make sure that's included
even when empty (technically, when empty there couldn't be any ref_addr
anyway - it only came up when gmlt didn't produce any (even non-empty)
pubnames - but given what that reveals about gold's implementation, this
seems like a good thing to do for consistency).

llvm-svn: 303894
2017-05-25 18:50:28 +00:00
David Blaikie 488393f822 DWARF: Avoid cross-CU references under Fission
Turns out that the Fission/Split DWARF package format (DWP) is currently
insufficient to handle cross-CU (ref_addr) references. So for now,
duplicate any debug info needed in these situations:
* inlined_subroutine's abstract_origin
* inlined variable's abstract_origin
* types

Keep the ref_addr behavior in general, including in the split DWARF
inline debug info that can be emitted into the object files for online
symbolication.
Keep a flag to use the old (ref_addr) behavior for testing ways of
addressing this limitation in the DWP tool (& for those not using DWP
packaging).

llvm-svn: 302858
2017-05-12 01:13:45 +00:00
Reid Kleckner b5fced7324 [codeview] Check for a DIExpression offset for local variables
Fixes inalloca parameters, which previously all pointed to the same
offset. Extend the test to use llvm-readobj so that we can test the
offset in a readable way.

llvm-svn: 302578
2017-05-09 19:59:29 +00:00
Reid Kleckner 3a363fff7e Re-land "Use the frame index side table for byval and inalloca arguments"
This re-lands r302483. It was not the cause of PR32977.

llvm-svn: 302544
2017-05-09 16:02:20 +00:00
Reid Kleckner 9f29914d40 Revert "Use the frame index side table for byval and inalloca arguments"
This reverts r302483 and it's follow up fix.

llvm-svn: 302493
2017-05-09 01:14:39 +00:00
Reid Kleckner 45efcf0c96 Use the frame index side table for byval and inalloca arguments
Summary:
For inalloca functions, this is a very common code pattern:

  %argpack = type <{ i32, i32, i32 }>
  define void @f(%argpack* inalloca %args) {
  entry:
    %a = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 0
    %b = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 1
    %c = getelementptr inbounds %argpack, %argpack* %args, i32 0, i32 2
    tail call void @llvm.dbg.declare(metadata i32* %a, ... "a")
    tail call void @llvm.dbg.declare(metadata i32* %c, ... "b")
    tail call void @llvm.dbg.declare(metadata i32* %b, ... "c")

Even though these GEPs can be simplified to a constant offset from EBP
or RSP, we don't do that at -O0, and each GEP is computed into a
register. Registers used to compute argument addresses are typically
spilled and clobbered very quickly after the initial computation, so
live debug variable tracking loses information very quickly if we use
DBG_VALUE instructions.

This change moves processing of dbg.declare between argument lowering
and basic block isel, so that we can ask if an argument has a frame
index or not. If the argument lives in a register as is the case for
byval arguments on some targets, then we don't put it in the side table
and during ISel we emit DBG_VALUE instructions.

Reviewers: aprantl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32980

llvm-svn: 302483
2017-05-08 23:20:27 +00:00
Adrian Prantl fed4f399d3 Remove line and file from DINamespace.
Fixes the issue highlighted in
http://lists.llvm.org/pipermail/cfe-dev/2014-June/037500.html.

The DW_AT_decl_file and DW_AT_decl_line attributes on namespaces can
prevent LLVM from uniquing types that are in the same namespace. They
also don't carry any meaningful information.

rdar://problem/17484998
Differential Revision: https://reviews.llvm.org/D32648

llvm-svn: 301706
2017-04-28 22:25:46 +00:00
Rui Ueyama 0fcbb2893e Revert r301487: Replace HashString algorithm with xxHash64
This reverts commit r301487 to make buildbots green.

llvm-svn: 301491
2017-04-26 23:15:10 +00:00
Rui Ueyama 87b30ac9d3 Replace HashString algorithm with xxHash64
The previous algorithm processed one character at a time, which is very
painful on a modern CPU. Replace it with xxHash64, which both already
exists in the codebase and is fairly fast.

Patch from Scott Smith!

Differential Revision: https://reviews.llvm.org/D32509

llvm-svn: 301487
2017-04-26 22:45:04 +00:00
Adrian Prantl dd21502482 Fix an assertion when skipping stack values in DWARF2 mode.
The fix consists of resetting LocationKind when addMachineRegExpression fails.

rdar://problem/31803010

llvm-svn: 301351
2017-04-25 19:40:53 +00:00
Adrian Prantl de1a8b4efb Print complete DIExpressions in the assembler output DEBUG_VALUE comments.
The previous code was complex, incorrect, and couldn't print everything.

llvm-svn: 301333
2017-04-25 17:22:09 +00:00