Commit Graph

37 Commits

Author SHA1 Message Date
Thomas Lively ca9ba76481 [WebAssembly] Replace all calls with generalized multivalue calls
Summary:
Extends the multivalue call infrastructure to tail calls, removes all
legacy calls specialized for particular result types, and removes the
CallIndirectFixup pass, since all indirect call arguments are now
fixed up directly in the post-insertion hook.

In order to keep supporting pretty-printed defs and uses in test
expectations, MCInstLower now inserts an immediate containing the
number of defs for each call and call_indirect. The InstPrinter is
updated to query this immediate if it is present and determine which
MCOperands are defs and uses accordingly.

Depends on D72902.

Reviewers: aheejin

Subscribers: dschuff, mgorny, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74192
2020-02-18 15:55:20 -08:00
Jinsong Ji 01edae1271 [AsmPrinter] Print FP constant in hexadecimal form instead
Printing floating point number in decimal is inconvenient for humans.
Verbose asm output will print out floating point values in comments, it
helps.

But in lots of cases, users still need additional work to covert the
decimal back to hex or binary to check the bit patterns,
especially when there are small precision difference.

Hexadecimal form is one of the supported form in LLVM IR, and easier for
debugging.

This patch try to print all FP constant in hex form instead.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D73566
2020-02-07 16:00:55 +00:00
Thomas Lively f3b4f99007 [WebAssembly] Remove uses of ThreadModel
Summary:
In the clang UI, replaces -mthread-model posix with -matomics as the
source of truth on threading. In the backend, replaces
-thread-model=posix with the atomics target feature, which is now
collected on the WebAssemblyTargetMachine along with all other used
features. These collected features will also be used to emit the
target features section in the future.

The default configuration for the backend is thread-model=posix and no
atomics, which was previously an invalid configuration. This change
makes the default valid because the thread model is ignored.

A side effect of this change is that objects are never emitted with
passive segments. It will instead be up to the linker to decide
whether sections should be active or passive based on whether atomics
are used in the final link.

Reviewers: aheejin, sbc100, dschuff

Subscribers: mehdi_amini, jgravelle-google, hiraditya, sunfish, steven_wu, dexonsmith, rupprecht, jfb, jdoerfert, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D58742

llvm-svn: 355112
2019-02-28 18:39:08 +00:00
Sam Clegg 275d15ecf3 [WebAssembly] Update CodeGen test expectations after rL354697. NFC
llvm-svn: 354705
2019-02-23 00:07:39 +00:00
Thomas Lively 2e1504091e [WebAssembly] Update MC for bulk memory
Summary:
Rename MemoryIndex to InitFlags and implement logic for determining
data segment layout in ObjectYAML and MC. Also adds a "passive" flag
for the .section assembler directive although this cannot be assembled
yet because the assembler does not support data sections.

Reviewers: sbc100, aardappel, aheejin, dschuff

Subscribers: jgravelle-google, hiraditya, sunfish, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57938

llvm-svn: 354397
2019-02-19 22:56:19 +00:00
Wouter van Oortmerssen 49482f824a [WebAssembly] replaced .param/.result by .functype
Summary:
This makes it easier/cleaner to generate a single signature from
this directive. Also:
- Adds the symbol name, such that we don't depend on the location
  of this directive anymore.
- Actually constructs the signature in the assembler, and make the
  assembler own it.
- Refactor the use of MVT vs ValType in the streamer and assembler
  to require less conversions overall.
- Changed 700 or so tests to use it.

Reviewers: sbc100, dschuff

Subscribers: jgravelle-google, eraman, aheejin, sunfish, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D54652

llvm-svn: 347228
2018-11-19 17:10:36 +00:00
Sam Clegg 74f5fd4e32 [WebAssembly] Default to static reloc model
Differential Revision: https://reviews.llvm.org/D54637

llvm-svn: 347073
2018-11-16 18:59:51 +00:00
Wouter van Oortmerssen 8a9cb242fb [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: sbc100, jgravelle-google, eraman, aheejin, llvm-commits, jfb

Differential Revision: https://reviews.llvm.org/D51241

llvm-svn: 340750
2018-08-27 15:45:51 +00:00
Wouter van Oortmerssen a7be375586 Revert "[WebAssembly] Added default stack-only instruction mode for MC."
This reverts commit 917a99b71ce21c975be7bfbf66f4040f965d9f3c.

llvm-svn: 339630
2018-08-13 23:12:49 +00:00
Wouter van Oortmerssen ab26bd0647 [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Moved Explicit Locals pass to last.
Made that pass obligatory.
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: jfb, llvm-commits, aheejin, eraman, jgravelle-google, sbc100

Differential Revision: https://reviews.llvm.org/D50568

llvm-svn: 339474
2018-08-10 21:32:47 +00:00
Wouter van Oortmerssen a90d24da1c Revert "[WebAssembly] Added default stack-only instruction mode for MC."
This reverts commit d3c9af4179eae7793d1487d652e2d4e23844555f.
(SVN revision 338164)

llvm-svn: 338176
2018-07-27 23:19:51 +00:00
Wouter van Oortmerssen a67c4137c3 [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Moved Explicit Locals pass to last.
Made that pass obligatory.
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: sbc100, jgravelle-google, eraman, aheejin, llvm-commits

Differential Revision: https://reviews.llvm.org/D49160

llvm-svn: 338164
2018-07-27 20:56:43 +00:00
Sam Clegg a5908009cd [WebAsembly] Update default triple in test files to wasm32-unknown-unkown.
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
2018-05-10 17:49:11 +00:00
Daniel Neilson 1e68724d24 Remove alignment argument from memcpy/memmove/memset in favour of alignment attributes (Step 1)
Summary:
 This is a resurrection of work first proposed and discussed in Aug 2015:
   http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.html
and initially landed (but then backed out) in Nov 2015:
   http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

 The @llvm.memcpy/memmove/memset intrinsics currently have an explicit argument
which is required to be a constant integer. It represents the alignment of the
dest (and source), and so must be the minimum of the actual alignment of the
two.

 This change is the first in a series that allows source and dest to each
have their own alignments by using the alignment attribute on their arguments.

 In this change we:
1) Remove the alignment argument.
2) Add alignment attributes to the source & dest arguments. We, temporarily,
   require that the alignments for source & dest be equal.

 For example, code which used to read:
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 100, i32 4, i1 false)
will now read
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %dest, i8* align 4 %src, i32 100, i1 false)

 Downstream users may have to update their lit tests that check for
@llvm.memcpy/memmove/memset call/declaration patterns. The following extended sed script
may help with updating the majority of your tests, but it does not catch all possible
patterns so some manual checking and updating will be required.

s~declare void @llvm\.mem(set|cpy|move)\.p([^(]*)\((.*), i32, i1\)~declare void @llvm.mem\1.p\2(\3, i1)~g
s~call void @llvm\.memset\.p([^(]*)i8\(i8([^*]*)\* (.*), i8 (.*), i8 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.memset.p\1i8(i8\2* \3, i8 \4, i8 \5, i1 \6)~g
s~call void @llvm\.memset\.p([^(]*)i16\(i8([^*]*)\* (.*), i8 (.*), i16 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.memset.p\1i16(i8\2* \3, i8 \4, i16 \5, i1 \6)~g
s~call void @llvm\.memset\.p([^(]*)i32\(i8([^*]*)\* (.*), i8 (.*), i32 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.memset.p\1i32(i8\2* \3, i8 \4, i32 \5, i1 \6)~g
s~call void @llvm\.memset\.p([^(]*)i64\(i8([^*]*)\* (.*), i8 (.*), i64 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.memset.p\1i64(i8\2* \3, i8 \4, i64 \5, i1 \6)~g
s~call void @llvm\.memset\.p([^(]*)i128\(i8([^*]*)\* (.*), i8 (.*), i128 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.memset.p\1i128(i8\2* \3, i8 \4, i128 \5, i1 \6)~g
s~call void @llvm\.memset\.p([^(]*)i8\(i8([^*]*)\* (.*), i8 (.*), i8 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.memset.p\1i8(i8\2* align \6 \3, i8 \4, i8 \5, i1 \7)~g
s~call void @llvm\.memset\.p([^(]*)i16\(i8([^*]*)\* (.*), i8 (.*), i16 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.memset.p\1i16(i8\2* align \6 \3, i8 \4, i16 \5, i1 \7)~g
s~call void @llvm\.memset\.p([^(]*)i32\(i8([^*]*)\* (.*), i8 (.*), i32 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.memset.p\1i32(i8\2* align \6 \3, i8 \4, i32 \5, i1 \7)~g
s~call void @llvm\.memset\.p([^(]*)i64\(i8([^*]*)\* (.*), i8 (.*), i64 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.memset.p\1i64(i8\2* align \6 \3, i8 \4, i64 \5, i1 \7)~g
s~call void @llvm\.memset\.p([^(]*)i128\(i8([^*]*)\* (.*), i8 (.*), i128 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.memset.p\1i128(i8\2* align \6 \3, i8 \4, i128 \5, i1 \7)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i8\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i8 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.mem\1.p\2i8(i8\3* \4, i8\5* \6, i8 \7, i1 \8)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i16\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i16 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.mem\1.p\2i16(i8\3* \4, i8\5* \6, i16 \7, i1 \8)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i32\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i32 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.mem\1.p\2i32(i8\3* \4, i8\5* \6, i32 \7, i1 \8)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i64\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i64 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.mem\1.p\2i64(i8\3* \4, i8\5* \6, i64 \7, i1 \8)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i128\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i128 (.*), i32 [01], i1 ([^)]*)\)~call void @llvm.mem\1.p\2i128(i8\3* \4, i8\5* \6, i128 \7, i1 \8)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i8\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i8 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.mem\1.p\2i8(i8\3* align \8 \4, i8\5* align \8 \6, i8 \7, i1 \9)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i16\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i16 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.mem\1.p\2i16(i8\3* align \8 \4, i8\5* align \8 \6, i16 \7, i1 \9)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i32\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i32 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.mem\1.p\2i32(i8\3* align \8 \4, i8\5* align \8 \6, i32 \7, i1 \9)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i64\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i64 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.mem\1.p\2i64(i8\3* align \8 \4, i8\5* align \8 \6, i64 \7, i1 \9)~g
s~call void @llvm\.mem(cpy|move)\.p([^(]*)i128\(i8([^*]*)\* (.*), i8([^*]*)\* (.*), i128 (.*), i32 ([0-9]*), i1 ([^)]*)\)~call void @llvm.mem\1.p\2i128(i8\3* align \8 \4, i8\5* align \8 \6, i128 \7, i1 \9)~g

 The remaining changes in the series will:
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
   source and dest alignments.
Step 3) Update Clang to use the new IRBuilder API.
Step 4) Update Polly to use the new IRBuilder API.
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
        and those that use use MemIntrinsicInst::[get|set]Alignment() to use
        getDestAlignment() and getSourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
        MemIntrinsicInst::[get|set]Alignment() methods.

Reviewers: pete, hfinkel, lhames, reames, bollu

Reviewed By: reames

Subscribers: niosHD, reames, jholewinski, qcolombet, jfb, sanjoy, arsenm, dschuff, dylanmckay, mehdi_amini, sdardis, nemanjai, david2050, nhaehnle, javed.absar, sbc100, jgravelle-google, eraman, aheejin, kbarton, JDevlieghere, asb, rbar, johnrusso, simoncook, jordy.potman.lists, apazos, sabuasal, llvm-commits

Differential Revision: https://reviews.llvm.org/D41675

llvm-svn: 322965
2018-01-19 17:13:12 +00:00
Dan Gohman 5cf6473903 [WebAssembly] Don't try to emit size information for unsized types
Patch by John Sully!

Fixes PR35164.

Differential Revision: https://reviews.llvm.org/D39519

llvm-svn: 319991
2017-12-07 00:14:30 +00:00
Dan Gohman 7d7409e553 [WebAssembly] Convert the remaining unit tests to the new wasm-object-file target.
To facilitate this, add a new hidden command-line option to disable
the explicit-locals pass. That causes llc to emit invalid code that doesn't
have all locals converted to get_local/set_local, however it simplifies
testwriting in many cases.

llvm-svn: 296540
2017-02-28 23:37:04 +00:00
Dan Gohman b7c2400fa7 [WebAssembly] Optimize away return instructions using fallthroughs.
This saves a small amount of code size, and is a first small step toward
passing values on the stack across block boundaries.

Differential Review: http://reviews.llvm.org/D20450

llvm-svn: 270294
2016-05-21 00:21:56 +00:00
Dan Gohman bdf08d5da6 [WebAssembly] Optimize memcpy/memmove/memcpy calls.
These calls return their first argument, but because LLVM uses an intrinsic
with a void return type, they can't use the returned attribute. Generalize
the store results pass to optimize these calls too.

llvm-svn: 258781
2016-01-26 04:01:11 +00:00
Dan Gohman 61d15ae4f5 [MC] Use .p2align instead of .align
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
2016-01-26 00:03:25 +00:00
Dan Gohman 5016c0f99d [SelectionDAG] Use the correct return type for memcpy, memmove, and memset.
When generating calls to memcpy, memmove, and memset, use void* as the return
type rather than void, to match the standard signatures for these functions.

This has no practical effect for most targets, since the return values of
these calls aren't being used anyway, and most calling conventions tolerate
this kind of mismatch. However, this change will help support future
optimizations to utilize the return value to avoid holding the argument
value live across a call.

llvm-svn: 258691
2016-01-25 15:05:56 +00:00
Dan Gohman 938ff9f0aa [WebAssembly] MCFixupKindInfo's TargetSize is in bits rather than bytes.
llvm-svn: 257655
2016-01-13 19:29:37 +00:00
Dan Gohman 26c6765bd6 [WebAssembly] Define WebAssembly-specific relocation codes.
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
2016-01-11 23:38:05 +00:00
JF Bastien b9ec4c6cea WebAssembly: use .skip instead of .zero directive
.zero is confusing when used with two arguments. Documentation:

  This directive emits SIZE 0-valued bytes.  SIZE must be an absolute
  expression.  This directive is actually an alias for the '.skip'
  directive so in can take an optional second argument of the value to
  store in the bytes instead of zero.  Using '.zero' in this way would be
  confusing however.

Ref: https://sourceware.org/bugzilla/show_bug.cgi?id=18353

Hexagon and Sparc do the same, and it's all the same to WebAssembly so
let's pick the less confusing of the two.

llvm-svn: 257111
2016-01-07 23:18:29 +00:00
Dan Gohman 0c6f5ac50a [WebAssembly] Add -m:e to the target triple.
This enables ELF-style name mangling, which primarily means using ".L" for
private symbols.

llvm-svn: 257020
2016-01-07 03:19:23 +00:00
Dan Gohman 670a60ed52 [WebAssembly] Switch WebAssemblyMCAsmInfo.h from MCAsmInfo to MCAsmInfoELF.
llvm-svn: 255925
2015-12-17 20:50:45 +00:00
Dan Gohman 4b9d7916ee [WebAssembly] Implement instruction selection for constant offsets in addresses.
Add instruction patterns for matching load and store instructions with constant
offsets in addresses. The code is fairly redundant due to the need to replicate
everything between imm, tglobaldadr, and texternalsym, but this appears to be
common tablegen practice. The main alternative appears to be to introduce
matching functions with C++ code, but sticking with purely generated matchers
seems better for now.

Also note that this doesn't yet support offsets from getelementptr, which will
be the most common case; that will depend on a change in target-independent code
in order to set the NoUnsignedWrap flag, which I'll submit separately. Until
then, the testcase uses ptrtoint+add+inttoptr with a nuw on the add.

Also implement isLegalAddressingMode with an approximation of this.

Differential Revision: http://reviews.llvm.org/D15538

llvm-svn: 255681
2015-12-15 22:01:29 +00:00
JF Bastien 65f0a71f40 WebAssembly: test global array indexing
This case was tested in the linker from code, but not from globals indexing into other globals. The linker currently barfs on this, ncbray volunteered to fix it.

llvm-svn: 255601
2015-12-15 02:02:51 +00:00
Dan Gohman e2a7a8278f [WebAssembly] Implement direct calls to external symbols.
llvm-svn: 254863
2015-12-05 20:41:36 +00:00
Derek Schuff 9d77952332 [WebAssembly] Support constant offsets on loads and stores
This is just prototype for load/store for i32 types. I'll add them to
the rest of the types if we like this direction.

Differential Revision: http://reviews.llvm.org/D15197

llvm-svn: 254807
2015-12-05 00:26:39 +00:00
Dan Gohman 81719f8555 [WebAssembly] Support for register stackifying with load and store instructions.
llvm-svn: 254076
2015-11-25 16:55:01 +00:00
Dan Gohman 2c8fe6a428 [WebAssembly] Codegen support for ISD::ExternalSymbol
llvm-svn: 254075
2015-11-25 16:44:29 +00:00
Dan Gohman 700515fa92 [WebAssembly] Suffix output operands with '='.
This distinguishes input operands from output operands. This is something of
a syntactic experiment to see whether the mild amount of clutter this adds is
outweighed by the extra information it conveys to the reader.

llvm-svn: 253922
2015-11-23 21:55:57 +00:00
Dan Gohman 4ba4816b97 [WebAssembly] Enable register coloring and register stackifying.
This also takes the push/pop syntax another step forward, introducing stack
slot numbers to make it easier to see how expressions are connected. For
example, the value pushed in $push7 is popped in $pop7.

And, this begins an experiment with making get_local and set_local implicit
when an operation directly uses or defines a register. This greatly reduces
clutter. If this experiment succeeds, it may make sense to do this for
const instructions as well.

And, this introduces more special code for ARGUMENTS; hopefully this code
will soon be obviated by proper support for live-in virtual registers.

llvm-svn: 253465
2015-11-18 16:12:01 +00:00
Derek Schuff 71e8169ea8 [WebAssembly] Fix printing of global operands
This was regressed in r252656 which wasn't quite NFC. Instead of using a
custom instruction as before, use a pattern to select CONST_I32 for the
global addrs.

Differential Revision: http://reviews.llvm.org/D14587

llvm-svn: 253276
2015-11-17 00:20:44 +00:00
Dan Gohman e51c058ecc [WebAssembly] Switch to a more traditional assembly syntax
This new syntax is built around putting each instruction on its own line
in a "mnemonic op, op, op" like syntax. It also uses conventional data
section directives like ".byte" and so on rather than requiring everything
to be in hierarchical S-expression format. This is a more natural syntax
for a ".s" file format from the perspective of LLVM MC and related tools,
while remaining easy to translate into other forms as needed.

llvm-svn: 249364
2015-10-06 00:27:55 +00:00
Dan Gohman 5e0668426c [WebAssembly] Update target datalayout strings.
llvm-svn: 247187
2015-09-09 20:54:31 +00:00
JF Bastien 45479f627a WebAssembly: handle private/internal globals.
Things of note:
 - Other linkage types aren't handled yet. We'll figure it out with dynamic linking.
 - Special LLVM globals are either ignored, or error out for now.
 - TLS isn't supported yet (WebAssembly will have threads later).
 - There currently isn't a syntax for alignment, I left it in a comment so it's easy to hook up.
 - Undef is convereted to whatever the type's appropriate null value is.
 - assert versus report_fatal_error: follow what other AsmPrinters do, and assert only on what should have been caught elsewhere.

llvm-svn: 246092
2015-08-26 22:09:54 +00:00