The large code model is documented at
http://www.x86-64.org/documentation/abi.pdf and says that calls should
assume their target doesn't live within the 32-bit pc-relative offset
that fits in the call instruction.
To do this, we turn off the global-address->target-global-address
conversion in X86TargetLowering::LowerCall(). The first attempt at
this broke the lazy JIT because it can separate the movabs(imm->reg)
from the actual call instruction. The lazy JIT receives the address of
the movabs as a relocation and needs to record the return address from
the call; and then when that call happens, it needs to patch the
movabs with the newly-compiled target. We could thread the call
instruction into the relocation and record the movabs<->call mapping
explicitly, but that seems to require at least as much new
complication in the code generator as this change.
To fix this, we make lazy functions _always_ go through a call
stub. You'd think we'd only have to force lazy calls through a stub on
difficult platforms, but that turns out to break indirect calls
through a function pointer. The right fix for that is to distinguish
between calls and address-of operations on uncompiled functions, but
that's complex enough to leave for someone else to do.
Another attempt at this defined a new CALL64i pseudo-instruction,
which expanded to a 2-instruction sequence in the assembly output and
was special-cased in the X86CodeEmitter's emitInstruction()
function. That broke indirect calls in the same way as above.
This patch also removes a hack forcing Darwin to the small code model.
Without far-call-stubs, the small code model requires things of the
JITMemoryManager that the DefaultJITMemoryManager can't provide.
Thanks to echristo for lots of testing!
llvm-svn: 88984
- This is an initial step towards -march=native support in Clang, and towards
eliminating host dependencies in the targets. See PR5389.
- Patch by Roman Divacky!
llvm-svn: 88768
Provide special isLoadFromStackSlotPostFE and isStoreToStackSlotPostFE
interfaces to explicitly request checking for post-frame ptr elimination
operands. This uses a heuristic so it isn't reliable for correctness.
llvm-svn: 87047
machine instruction loads or stores from/to a stack slot. Unlike
isLoadFromStackSlot and isStoreFromStackSlot, the instruction may be
something other than a pure load/store (e.g. it may be an arithmetic
operation with a memory operand). This helps AsmPrinter determine when
to print a spill/reload comment.
This is only a hint since we may not be able to figure this out in all
cases. As such, it should not be relied upon for correctness.
Implement for X86. Return false by default for other architectures.
llvm-svn: 87026
slots. The AsmPrinter will use this information to determine whether to
print a spill/reload comment.
Remove default argument values. It's too easy to pass a wrong argument
value when multiple arguments have default values. Make everything
explicit to trap bugs early.
Update all targets to adhere to the new interfaces..
llvm-svn: 87022
- Force NDEBUG on in any Release build. This drops the compile time to ~100s
from ~600s, in Release mode.
- This may just be a temporary workaround, I don't know the true nature of the
gcc-4.2 compile time performance problem.
llvm-svn: 86695
This patch forbids implicit conversion of DenseMap::const_iterator to
DenseMap::iterator which was possible because DenseMapIterator inherited
(publicly) from DenseMapConstIterator. Conversion the other way around is now
allowed as one may expect.
The template DenseMapConstIterator is removed and the template parameter
IsConst which specifies whether the iterator is constant is added to
DenseMapIterator.
Actually IsConst parameter is not necessary since the constness can be
determined from KeyT but this is not relevant to the fix and can be addressed
later.
Patch by Victor Zverovich!
llvm-svn: 86636
1. rename the movhp patfrag to movlhps, since thats what it actually matches
2. eliminate the bogus movhps load and store patterns, they were incorrect. The load transforms are already handled (correctly) by shufps/unpack.
3. revert a recent test change to its correct form.
llvm-svn: 86415
MachineRelocations, "stub" always refers to a far-call stub or a
load-a-faraway-global stub, so this patch adds "Far" to the term. (Other stubs
are used for lazy compilation and dlsym address replacement.) The variable was
also inconsistent between the positive and negative sense, and the positive
sense ("NeedStub") was more demanding than is accurate (since a nearby-enough
function can be called directly even if the platform often requires a stub).
Since the negative sense causes double-negatives, I switched to
"MayNeedFarStub" globally.
llvm-svn: 86363
The KILL pseudo-instruction may survive to the asm printer pass, just like the IMPLICIT_DEF. Print the KILL as a comment instead of just leaving a blank line in the output.
With -asm-verbose=0, a blank line is printed, like IMPLICIT?DEF.
llvm-svn: 86041
the testcase into:
_test1: ## @test1
## BB#0: ## %entry
leaq L_test1_bb6(%rip), %rax
jmpq *%rax
L_test1_bb: ## Address Taken
LBB1_1: ## %bb
movb $1, %al
ret
L_test1_bb6: ## Address Taken
LBB1_2: ## %bb6
movb $2, %al
ret
Note, it is very very strange that BlockAddressSDNode doesn't carry
around TargetFlags. Dan, please fix this.
llvm-svn: 85703
unfolding loads for hoisting. getOpcodeAfterMemoryUnfold returns the
opcode of the original operation without the load, not the load
itself, MachineLICM needs to know the operand index in order to get
the correct register class. Extend getOpcodeAfterMemoryUnfold to
return this information.
llvm-svn: 85622
bunch of associated comments, because it doesn't have anything to do
with DAGs or scheduling. This is another step in decoupling MachineInstr
emitting from scheduling.
llvm-svn: 85517
Devang Patel