Commit Graph

16932 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
fc6374439e Add VirtRegMap::hasKnownPreference().
Virtual registers with a known preferred register are prioritized by
RAGreedy. This function makes the condition explicit without depending
on getRegAllocPref().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169179 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 23:23:50 +00:00
Nadav Rotem
b8f842dce4 minor renaming, documentation and cleanups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169175 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 22:57:09 +00:00
Michael J. Spencer
6bc86018d1 [Support] Make FileOutputBuffer work on Windows.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169167 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 22:09:52 +00:00
Pedro Artigas
49eb628c21 moves doInitialization and doFinalization to the Pass class and removes some unreachable code in MachineModuleInfo
reviewed by Evan Cheng <evan.cheng@apple.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169164 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 21:56:57 +00:00
Argyrios Kyrtzidis
f7e78487de Add a getMemorySize() function for DenseSet.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169163 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 21:46:21 +00:00
Jakob Stoklund Olesen
7eafc3e7be Add a new hook for providing register allocator hints more flexibly.
The TargetRegisterInfo::getRegAllocationHints() function is going to
replace the existing mechanisms for providing target-dependent hints to
the register allocator: ResolveRegAllocHint() and
getRawAllocationOrder().

The new hook is more flexible because it allows the target to provide
multiple preferred candidate registers for each virtual register, and it
is easier to use because targets are not required to return a reference
to a constant array like getRawAllocationOrder().

An optional VirtRegMap argument can be used to provide target-dependent
hints that depend on the provisional assignments of other virtual
registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169154 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 21:17:00 +00:00
Argyrios Kyrtzidis
acb8d9fbe3 Eliminate redundant bitwise operations when using a llvm/ADT/PointerUnion.
For comparison, with this code sample:

PointerUnion<int *, char *> Data;
PointerUnion<int *, char *> foo1() {
	Data = new int;
	return new int;
}
PointerUnion<int *, char *> foo2() {
	Data = new char;
	return new char;
}

Before this patch we would get:

define i64 @_Z4foo1v() uwtable ssp {
  %1 = tail call noalias i8* @_Znwm(i64 4)
  %2 = ptrtoint i8* %1 to i64
  %3 = load i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %4 = and i64 %3, 1
  %.masked.i = and i64 %2, -3
  %5 = or i64 %4, %.masked.i
  store i64 %5, i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %6 = tail call noalias i8* @_Znwm(i64 4)
  %7 = ptrtoint i8* %6 to i64
  %8 = and i64 %7, -3
  ret i64 %8
}

define i64 @_Z4foo2v() uwtable ssp {
  %1 = tail call noalias i8* @_Znwm(i64 1)
  %2 = ptrtoint i8* %1 to i64
  %3 = load i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %4 = and i64 %3, 1
  %5 = or i64 %2, %4
  %6 = or i64 %5, 2
  store i64 %6, i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %7 = tail call noalias i8* @_Znwm(i64 1)
  %8 = ptrtoint i8* %7 to i64
  %9 = or i64 %8, 2
  ret i64 %9
}

After the patch:

define i64 @_Z4foo1v() uwtable ssp {
  %1 = tail call noalias i8* @_Znwm(i64 4)
  %2 = ptrtoint i8* %1 to i64
  store i64 %2, i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %3 = tail call noalias i8* @_Znwm(i64 4)
  %4 = ptrtoint i8* %3 to i64
  ret i64 %4
}

declare noalias i8* @_Znwm(i64)

define i64 @_Z4foo2v() uwtable ssp {
  %1 = tail call noalias i8* @_Znwm(i64 1)
  %2 = ptrtoint i8* %1 to i64
  %3 = or i64 %2, 2
  store i64 %3, i64* getelementptr inbounds (%"class.llvm::PointerUnion"* @Data, i64 0, i32 0, i32 0), align 8
  %4 = tail call noalias i8* @_Znwm(i64 1)
  %5 = ptrtoint i8* %4 to i64
  %6 = or i64 %5, 2
  ret i64 %6
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169147 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 19:59:23 +00:00
Bill Wendling
9127be8a19 Add 'getInt64Field()' method to get the signed integer instead of unsigned.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169145 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 19:44:25 +00:00
Alexey Samsonov
b0dcf61252 ASan: add blacklist file to ASan pass options. Clang patch for this will follow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169143 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 19:09:26 +00:00
Chandler Carruth
255f89faee Sort the #include lines for the include/... tree with the script.
AKA: Recompile *ALL* the source code!

This one went much better. No manual edits here. I spot-checked for
silliness and grep-checked for really broken edits and everything seemed
good. It all still compiles. Yell if you see something that looks goofy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169133 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 17:02:12 +00:00
Chandler Carruth
d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00
James Molloy
4fe6d0341d Remove bugzilla link.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169091 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-01 14:44:23 +00:00
Andrew Trick
657b75b994 misched: Fix RegisterPressureTracker handling of DebugVals.
Assertion failed: (TopRPTracker.getPos() == RegionBegin && "bad initial Top tracker").
rdar://12790302.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169072 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-01 01:22:49 +00:00
Bill Wendling
08510b14d4 Replace r168930 with a more reasonable patch.
The original patch removed a bunch of code that the SjLjEHPrepare pass placed
into the entry block if all of the landing pads were removed during the
CodeGenPrepare class. The more natural way of doing things is to run the CGP
*before* we run the SjLjEHPrepare pass.

Make it so!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169044 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 22:08:55 +00:00
Chandler Carruth
4334dd96a9 Switch LLVM_USE_RVALUE_REFERENCES to LLVM_HAS_RVALUE_REFERENCES.
Rationale:
1) This was the name in the comment block. ;]
2) It matches Clang's __has_feature naming convention.
3) It matches other compiler-feature-test conventions.

Sorry for the noise. =]

I've also switch the comment block to use a \brief tag and not duplicate
the name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168996 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 11:45:22 +00:00
Chandler Carruth
a5bf44b0b3 Separate out the tests for whether the compiler suports R-value
references from whether it supports an R-value reference *this. No
version of GCC today supports the latter, which breaks GCC C++11
compiles of LLVM and Clang now.

Also add doxygen comments clarifying what's going on here, and update
the usage in Optional. I'll update the usages in Clang next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168993 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 11:04:18 +00:00
Patrik Hagglund
58b4553549 More strict error checking in parseSpecifier + simplified code.
For example, don't allow empty strings to be passed to getInt.

Move asserts inside parseSpecifier. (One day we may want to pass parse
error messages to the user - from LLParser - instead of using asserts,
but keep the code simple until then. There have been an attempt to do
this. See r142288, which got reverted, and r142605.)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168991 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 10:06:59 +00:00
Eric Christopher
67587f462e Add the rest of the experimental fission sections to MC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168986 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 06:47:06 +00:00
Chandler Carruth
84bcf93e0f Move the InstVisitor utility into VMCore where it belongs. It heavily
depends on the IR infrastructure, there is no sense in it being off in
Support land.

This is in preparation to start working to expand InstVisitor into more
special-purpose visitors that are still generic and can be re-used
across different passes. The expansion will go into the Analylis tree
though as nothing in VMCore needs it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168972 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 03:08:41 +00:00
Jordan Rose
adf0c3d82d Add a new C++11 compatibility macro, LLVM_LVALUE_FUNCTION.
This expands to '&', and is intended to be used when an /optional/ rvalue
override is available.

Before:
  void foo() const { ... }

After:
  void foo() const LLVM_LVALUE_FUNCTION { ... }
  void foo() && { ... }

This is used to allow moving the contents of an Optional.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168963 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-30 00:38:53 +00:00
Dan Gohman
c63ee60ef0 Update comment for malloc being a library call now, rather than an instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168946 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 21:58:47 +00:00
Michael Ilseman
4b896dd613 copyFastMathFlags utility and test case
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168943 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 21:25:12 +00:00
Chad Rosier
33634833aa Whitespace.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168937 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 20:58:08 +00:00
Chad Rosier
a04d6c948c Fix 80-column violations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168936 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 20:56:58 +00:00
Shuxin Yang
84fca61ca5 rdar://12100355 (part 1)
This revision attempts to recognize following population-count pattern:

 while(a) { c++; ... ; a &= a - 1; ... },
  where <c> and <a>could be used multiple times in the loop body.

 TODO: On X8664 and ARM, __buildin_ctpop() are not expanded to a efficent 
instruction sequence, which need to be improved in the following commits.

Reviewed by Nadav, really appreciate!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168931 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 19:38:54 +00:00
Jim Grosbach
596e474101 Fix a memory leak in MachOObjectFile.
MachOObjectFile owns a MachOObj, but never frees it. Both MachOObjectFile
and MachOObj want to own the MemoryBuffer, though, so we have to be careful
and give them each one of their own.

Thanks to Greg Clayton, Eric Christopher and Michael Spencer for helping
figure out what's going wrong here.

rdar://12561773

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168923 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 19:14:11 +00:00
Alexey Samsonov
ee548275c6 Add options to AddressSanitizer passes to make them configurable by frontend.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168910 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 18:14:24 +00:00
Pedro Artigas
6eda081345 One more step towards making doInitialization and doFinalization useful for
start up and clean up module passes, now that ASAN and TSAN are fixed the
tests pass



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168905 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 17:47:05 +00:00
Justin Holewinski
3d200255d5 Allow targets to prefer TypeSplitVector over TypePromoteInteger when computing the legalization method for vectors
For some targets, it is desirable to prefer scalarizing <N x i1> instead of promoting to a larger legal type, such as <N x i32>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168882 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 14:26:24 +00:00
Evgeniy Stepanov
aa4f97d6ed Initial commit of MemorySanitizer.
Compiler pass only.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168866 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 09:57:20 +00:00
Jakob Stoklund Olesen
39b5c0c049 Use MCPhysReg for RegisterClassInfo allocation orders.
This saves a bit of memory.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168852 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 03:34:17 +00:00
Jakob Stoklund Olesen
e26e8a64ab Add an MCPhysReg typedef to replace naked uint16_t.
Use this type for arrays of physical registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168850 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 02:39:28 +00:00
Shuxin Yang
9b7f6f2de8 Instruction::isAssociative() returns true for fmul/fadd if they are tagged "unsafe" mode.
Approved by: Eli and Michael.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168848 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-29 01:47:31 +00:00
Michael Ilseman
9992bf75fc Fast-math: Extend IRBuilder to have settable FastMathFlags to create instructions with
Also extended IRBuilder's documentation to mention the convenience state for DefaultFPMathTag and FastMathFlags that can be set.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168812 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 21:16:19 +00:00
Michael Ilseman
0d38424bbe Fast-math comments and convenience method
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168811 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 21:11:25 +00:00
Jakob Stoklund Olesen
1ead68d769 Make the LiveRegMatrix analysis available to targets.
No functional change, just moved header files.

Targets can inject custom passes between register allocation and
rewriting. This makes it possible to tweak the register allocation
before rewriting, using the full global interference checking available
from LiveRegMatrix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168806 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 19:13:06 +00:00
Eli Bendersky
6b731486d4 Add backreference matching capabilities to Support/Regex, with
appropriate unit tests. This change in itself is not expected to
affect any functionality at this point, but it will serve as a
stepping stone to improve FileCheck's variable matching capabilities.

Luckily, our regex implementation already supports backreferences,
although a bit of hacking is required to enable it. It supports both
Basic Regular Expressions (BREs) and Extended Regular Expressions
(EREs), without supporting backrefs for EREs, following POSIX strictly
in this respect. And EREs is what we actually use (rightly). This is
contrary to many implementations (including the default on Linux) of
POSIX regexes, that do allow backrefs in EREs.

Adding backref support to our EREs is a very simple change in the
regcomp parsing code. I fail to think of significant cases where it
would clash with existing things, and can bring more versatility to
the regexes we write. There's always the danger of a backref in a
specially crafted regex causing exponential matching times, but since
we mainly use them for testing purposes I don't think it's a big
problem. [it can also be placed behind a flag specific to FileCheck,
if needed].

For more details, see:

* http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-November/055840.html
* http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20121126/156878.html



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168802 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 19:00:02 +00:00
Kostya Serebryany
1416edc30a [asan] Split AddressSanitizer into two passes (FunctionPass, ModulePass), LLVM part. This requires a clang part which will follow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168781 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 10:31:36 +00:00
Bill Wendling
3defc0bfa6 Add back support for reading and parsing 'deplibs'.
This is for backwards compatibility for pre-3.x bc files. The code reads the
code, but does nothing with it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168779 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 08:41:48 +00:00
Andrew Trick
8b1496c922 misched: Analysis that partitions the DAG into subtrees.
This is a simple, cheap infrastructure for analyzing the shape of a
DAG. It recognizes uniform DAGs that take the shape of bottom-up
subtrees, such as the included matrix multiplication example. This is
useful for heuristics that balance register pressure with ILP. Two
canonical expressions of the heuristic are implemented in scheduling
modes: -misched-ilpmin and -misched-ilpmax.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168773 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 05:13:28 +00:00
Andrew Trick
53e98a2c4a misched: rename ScheduleDAGILP to ScheduleDFS to prepare for other heuristics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168772 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 05:13:24 +00:00
Eric Christopher
6acb53152c Add brief support for the fission .debug_info.dwo section for
ELF output.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168764 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 02:49:38 +00:00
Eric Christopher
915e46fd96 Rearrange ordering of sections.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168762 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 02:49:32 +00:00
Eric Christopher
43e1d7aded Move and comment accessor routines.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168761 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 02:49:28 +00:00
Jakob Stoklund Olesen
a9fa4fd973 Remove all references to TargetInstrInfoImpl.
This class has been merged into its super-class TargetInstrInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168760 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 02:35:17 +00:00
Jakob Stoklund Olesen
fa2d98632c Move the guts of TargetInstrInfoImpl into the TargetInstrInfo class.
The *Impl class no longer serves a purpose now that the super-class
implementation is in CodeGen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168759 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 02:35:13 +00:00
Andrew Kaylor
8213068f34 Fix comment formatting in RuntimeDyld.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168739 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 22:53:57 +00:00
Andrew Kaylor
927ba6a0b3 Moving SectionMemoryManager into RuntimeDyld and adding unit tests for it.
The SectionMemoryManager now supports (and requires) applying section-specific page permissions.  Clients using this memory manager must call either MCJIT::finalizeObject() or SectionMemoryManager::applyPermissions() before executing JITed code.

See r168718 for changes from the previous implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168721 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 19:42:02 +00:00
Pedro Artigas
4bfea7685d Test commit only modifying comments
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168709 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 17:39:20 +00:00
Bill Schmidt
34a9d4b3b9 This patch implements medium code model support for 64-bit PowerPC.
The default for 64-bit PowerPC is small code model, in which TOC entries
must be addressable using a 16-bit offset from the TOC pointer.  Additionally,
only TOC entries are addressed via the TOC pointer.

With medium code model, TOC entries and data sections can all be addressed
via the TOC pointer using a 32-bit offset.  Cooperation with the linker
allows 16-bit offsets to be used when these are sufficient, reducing the
number of extra instructions that need to be executed.  Medium code model
also does not generate explicit TOC entries in ".section toc" for variables
that are wholly internal to the compilation unit.

Consider a load of an external 4-byte integer.  With small code model, the
compiler generates:

	ld 3, .LC1@toc(2)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc ei[TC],ei

With medium model, it instead generates:

	addis 3, 2, .LC1@toc@ha
	ld 3, .LC1@toc@l(3)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc ei[TC],ei

Here .LC1@toc@ha is a relocation requesting the upper 16 bits of the
32-bit offset of ei's TOC entry from the TOC base pointer.  Similarly,
.LC1@toc@l is a relocation requesting the lower 16 bits.  Note that if
the linker determines that ei's TOC entry is within a 16-bit offset of
the TOC base pointer, it will replace the "addis" with a "nop", and
replace the "ld" with the identical "ld" instruction from the small
code model example.

Consider next a load of a function-scope static integer.  For small code
model, the compiler generates:

	ld 3, .LC1@toc(2)
	lwz 4, 0(3)

	.section	.toc,"aw",@progbits
.LC1:
	.tc test_fn_static.si[TC],test_fn_static.si
	.type	test_fn_static.si,@object
	.local	test_fn_static.si
	.comm	test_fn_static.si,4,4

For medium code model, the compiler generates:

	addis 3, 2, test_fn_static.si@toc@ha
	addi 3, 3, test_fn_static.si@toc@l
	lwz 4, 0(3)

	.type	test_fn_static.si,@object
	.local	test_fn_static.si
	.comm	test_fn_static.si,4,4

Again, the linker may replace the "addis" with a "nop", calculating only
a 16-bit offset when this is sufficient.

Note that it would be more efficient for the compiler to generate:

	addis 3, 2, test_fn_static.si@toc@ha
        lwz 4, test_fn_static.si@toc@l(3)

The current patch does not perform this optimization yet.  This will be
addressed as a peephole optimization in a later patch.

For the moment, the default code model for 64-bit PowerPC will remain the
small code model.  We plan to eventually change the default to medium code
model, which matches current upstream GCC behavior.  Note that the different
code models are ABI-compatible, so code compiled with different models will
be linked and execute correctly.

I've tested the regression suite and the application/benchmark test suite in
two ways:  Once with the patch as submitted here, and once with additional
logic to force medium code model as the default.  The tests all compile
cleanly, with one exception.  The mandel-2 application test fails due to an
unrelated ABI compatibility with passing complex numbers.  It just so happens
that small code model was incredibly lucky, in that temporary values in 
floating-point registers held the expected values needed by the external
library routine that was called incorrectly.  My current thought is to correct
the ABI problems with _Complex before making medium code model the default,
to avoid introducing this "regression."

Here are a few comments on how the patch works, since the selection code
can be difficult to follow:

The existing logic for small code model defines three pseudo-instructions:
LDtoc for most uses, LDtocJTI for jump table addresses, and LDtocCPT for
constant pool addresses.  These are expanded by SelectCodeCommon().  The
pseudo-instruction approach doesn't work for medium code model, because
we need to generate two instructions when we match the same pattern.
Instead, new logic in PPCDAGToDAGISel::Select() intercepts the TOC_ENTRY
node for medium code model, and generates an ADDIStocHA followed by either
a LDtocL or an ADDItocL.  These new node types correspond naturally to
the sequences described above.

The addis/ld sequence is generated for the following cases:
 * Jump table addresses
 * Function addresses
 * External global variables
 * Tentative definitions of global variables (common linkage)

The addis/addi sequence is generated for the following cases:
 * Constant pool entries
 * File-scope static global variables
 * Function-scope static variables

Expanding to the two-instruction sequences at select time exposes the
instructions to subsequent optimization, particularly scheduling.

The rest of the processing occurs at assembly time, in
PPCAsmPrinter::EmitInstruction.  Each of the instructions is converted to
a "real" PowerPC instruction.  When a TOC entry needs to be created, this
is done here in the same manner as for the existing LDtoc, LDtocJTI, and
LDtocCPT pseudo-instructions (I factored out a new routine to handle this).

I had originally thought that if a TOC entry was needed for LDtocL or
ADDItocL, it would already have been generated for the previous ADDIStocHA.
However, at higher optimization levels, the ADDIStocHA may appear in a 
different block, which may be assembled textually following the block
containing the LDtocL or ADDItocL.  So it is necessary to include the
possibility of creating a new TOC entry for those two instructions.

Note that for LDtocL, we generate a new form of LD called LDrs.  This
allows specifying the @toc@l relocation for the offset field of the LD
instruction (i.e., the offset is replaced by a SymbolLo relocation).
When the peephole optimization described above is added, we will need
to do similar things for all immediate-form load and store operations.

The seven "mcm-n.ll" test cases are kept separate because otherwise the
intermingling of various TOC entries and so forth makes the tests fragile
and hard to understand.

The above assumes use of an external assembler.  For use of the
integrated assembler, new relocations are added and used by
PPCELFObjectWriter.  Testing is done with "mcm-obj.ll", which tests for
proper generation of the various relocations for the same sequences
tested with the external assembler.






git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168708 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 17:35:46 +00:00