Commit Graph

9 Commits

Author SHA1 Message Date
Geoff Berry b51774ac8c [MIRPrinter] Print raw branch probabilities as expected by MIRParser
Fixes PR28751.

Reviewers: MatzeB, qcolombet

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D26775

llvm-svn: 287368
2016-11-18 19:37:24 +00:00
Matthias Braun 538859cca3 llc: Add support for -run-pass none
This does not schedule any passes besides the ones necessary to
construct and print the machine function. This is useful to test .mir
file reading and printing.

Differential Revision: http://reviews.llvm.org/D22432

llvm-svn: 275664
2016-07-16 02:24:59 +00:00
Quentin Colombet 545e558b82 [MIR] Print on the given output instead of stderr.
Currently the MIR framework prints all its outputs (errors and actual
representation) on stderr.

This patch fixes that by printing the regular output in the output
specified with -o.

Differential Revision: http://reviews.llvm.org/D22251

llvm-svn: 275314
2016-07-13 20:36:03 +00:00
Justin Lebar c75d566f56 When printing MIR, output to errs() rather than outs().
Summary:
Without this, this command

  $ llvm-run llc -stop-after machine-cp -o - <( echo '' )

outputs an error, because we close stdout twice -- once when closing the
file opened for "-o", and again when closing outs().

Also clarify in the outs() definition that you can't ever call it if you
want to open your own raw_fd_ostream on stdout.

Reviewers: jroelofs, tstellarAMD

Subscribers: jholewinski, qcolombet, dsanders, llvm-commits

Differential Revision: http://reviews.llvm.org/D17422

llvm-svn: 261286
2016-02-19 00:18:46 +00:00
Cong Hou d97c100dc4 Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces.
(This is the second attempt to submit this patch. The first caused two assertion
 failures and was reverted. See https://llvm.org/bugs/show_bug.cgi?id=25687)

The patch in http://reviews.llvm.org/D13745 is broken into four parts:

1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.

This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.

All uses of weight-based interfaces are now updated to use probability-based
ones.


Differential revision: http://reviews.llvm.org/D14973

llvm-svn: 254377
2015-12-01 05:29:22 +00:00
Hans Wennborg 1dbaf67537 Revert r254348: "Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces."
and the follow-up r254356: "Fix a bug in MachineBlockPlacement that may cause assertion failure during BranchProbability construction."

Asserts were firing in Chromium builds. See PR25687.

llvm-svn: 254366
2015-12-01 03:49:42 +00:00
Cong Hou fa1917c673 Replace all weight-based interfaces in MBB with probability-based interfaces, and update all uses of old interfaces.
The patch in http://reviews.llvm.org/D13745 is broken into four parts:

1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.

This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.

All uses of weight-based interfaces are now updated to use probability-based
ones.


Differential revision: http://reviews.llvm.org/D14973

llvm-svn: 254348
2015-12-01 00:02:51 +00:00
Cong Hou 07eeb8001e Create a new interface addSuccessorWithoutWeight(MBB*) in MBB to add successors when optimization is disabled.
When optimization is disabled, edge weights that are stored in MBB won't be used so that we don't have to store them. Currently, this is done by adding successors with default weight 0, and if all successors have default weights, the weight list will be empty. But that the weight list is empty doesn't mean disabled optimization (as is stated several times in MachineBasicBlock.cpp): it may also mean all successors just have default weights.

We should discourage using default weights when adding successors, because it is very easy for users to forget update the correct edge weights instead of using default ones (one exception is that the MBB only has one successor). In order to detect such usages, it is better to differentiate using default weights from the case when optimizations is disabled.

In this patch, a new interface addSuccessorWithoutWeight(MBB*) is created for when optimization is disabled. In this case, MBB will try to maintain an empty weight list, but it cannot guarantee this as for many uses of addSuccessor() whether optimization is disabled or not is not checked. But it can guarantee that if optimization is enabled, then the weight list always has the same size of the successor list.

Differential revision: http://reviews.llvm.org/D13963

llvm-svn: 251429
2015-10-27 17:59:36 +00:00
Alex Lorenz 5022f6bb81 MIR Serialization: Change MIR syntax - use custom syntax for MBBs.
This commit modifies the way the machine basic blocks are serialized - now the
machine basic blocks are serialized using a custom syntax instead of relying on
YAML primitives. Instead of using YAML mappings to represent the individual
machine basic blocks in a machine function's body, the new syntax uses a single
YAML block scalar which contains all of the machine basic blocks and
instructions for that function.

This is an example of a function's body that uses the old syntax:

    body:
      - id: 0
        name: entry
        instructions:
          - '%eax = MOV32r0 implicit-def %eflags'
          - 'RETQ %eax'
    ...

The same body is now written like this:

    body: |
      bb.0.entry:
        %eax = MOV32r0 implicit-def %eflags
        RETQ %eax
    ...

This syntax change is motivated by the fact that the bundled machine
instructions didn't map that well to the old syntax which was using a single
YAML sequence to store all of the machine instructions in a block. The bundled
machine instructions internally use flags like BundledPred and BundledSucc to
determine the bundles, and serializing them as MI flags using the old syntax
would have had a negative impact on the readability and the ease of editing
for MIR files. The new syntax allows me to serialize the bundled machine
instructions using a block construct without relying on the internal flags,
for example:

   BUNDLE implicit-def dead %itstate, implicit-def %s1 ... {
      t2IT 1, 24, implicit-def %itstate
      %s1 = VMOVS killed %s0, 1, killed %cpsr, implicit killed %itstate
   }

This commit also converts the MIR testcases to the new syntax. I developed
a script that can convert from the old syntax to the new one. I will post the
script on the llvm-commits mailing list in the thread for this commit.

llvm-svn: 244982
2015-08-13 23:10:16 +00:00