Commit Graph

3 Commits

Author SHA1 Message Date
Akira Hatanaka bc497c93f5 Use function attribute "stackrealign" to decide whether stack
realignment should be forced.

With this commit, we can now force stack realignment when doing LTO and
do so on a per-function basis. Also, add a new cl::opt option
"stackrealign" to CommandFlags.h which is used to force stack
realignment via llc's command line.

Out-of-tree projects currently using -force-align-stack to force stack
realignment should make changes to attach the attribute to the functions
in the IR.

Differential Revision: http://reviews.llvm.org/D11814

llvm-svn: 247450
2015-09-11 18:54:38 +00:00
Duncan P. N. Exon Smith be7ea19b58 IR: Make metadata typeless in assembly
Now that `Metadata` is typeless, reflect that in the assembly.  These
are the matching assembly changes for the metadata/value split in
r223802.

  - Only use the `metadata` type when referencing metadata from a call
    intrinsic -- i.e., only when it's used as a `Value`.

  - Stop pretending that `ValueAsMetadata` is wrapped in an `MDNode`
    when referencing it from call intrinsics.

So, assembly like this:

    define @foo(i32 %v) {
      call void @llvm.foo(metadata !{i32 %v}, metadata !0)
      call void @llvm.foo(metadata !{i32 7}, metadata !0)
      call void @llvm.foo(metadata !1, metadata !0)
      call void @llvm.foo(metadata !3, metadata !0)
      call void @llvm.foo(metadata !{metadata !3}, metadata !0)
      ret void, !bar !2
    }
    !0 = metadata !{metadata !2}
    !1 = metadata !{i32* @global}
    !2 = metadata !{metadata !3}
    !3 = metadata !{}

turns into this:

    define @foo(i32 %v) {
      call void @llvm.foo(metadata i32 %v, metadata !0)
      call void @llvm.foo(metadata i32 7, metadata !0)
      call void @llvm.foo(metadata i32* @global, metadata !0)
      call void @llvm.foo(metadata !3, metadata !0)
      call void @llvm.foo(metadata !{!3}, metadata !0)
      ret void, !bar !2
    }
    !0 = !{!2}
    !1 = !{i32* @global}
    !2 = !{!3}
    !3 = !{}

I wrote an upgrade script that handled almost all of the tests in llvm
and many of the tests in cfe (even handling many `CHECK` lines).  I've
attached it (or will attach it in a moment if you're speedy) to PR21532
to help everyone update their out-of-tree testcases.

This is part of PR21532.

llvm-svn: 224257
2014-12-15 19:07:53 +00:00
Alexey Samsonov dcc1291d17 This CL changes the function prologue and epilogue emitted on X86 when stack needs realignment.
It is intended to fix PR11468.

Old prologue and epilogue looked like this:
push %rbp
mov %rsp, %rbp
and $alignment, %rsp
push %r14
push %r15
...
pop %r15
pop %r14
mov %rbp, %rsp
pop %rbp

The problem was to reference the locations of callee-saved registers in exception handling:
locations of callee-saved had to be re-calculated regarding the stack alignment operation. It would
take some effort to implement this in LLVM, as currently MachineLocation can only have the form
"Register + Offset". Funciton prologue and epilogue are now changed to:

push %rbp
mov %rsp, %rbp
push %14
push %15
and $alignment, %rsp
...
lea -$size_of_saved_registers(%rbp), %rsp
pop %r15
pop %r14
pop %rbp

Reviewed by Chad Rosier.

llvm-svn: 160248
2012-07-16 06:54:09 +00:00