LLVM emits stack probes on Windows targets to ensure that the stack is
correctly accessed. However, the amount of stack allocated before
emitting such a probe is hardcoded to 4096.
It is desirable to have this be configurable so that a function might
opt-out of stack probes. Our level of granularity is at the function
level instead of, say, the module level to permit proper generation of
code after LTO.
Patch by Andrew H!
N.B. The inliner needs to be updated to properly consider what happens
after inlining a function with a specific stack-probe-size into another
function with a different stack-probe-size.
llvm-svn: 225360
The assembler backend will relax to the long form if necessary. This removes a swap from long form to short form in the MCInstLowering code. Selecting the long form used to be required by the old JIT.
llvm-svn: 225242
Under the large code model, we cannot assume that __morestack lives within
2^31 bytes of the call site, so we cannot use pc-relative addressing. We
cannot perform the call via a temporary register, as the rax register may
be used to store the static chain, and all other suitable registers may be
either callee-save or used for parameter passing. We cannot use the stack
at this point either because __morestack manipulates the stack directly.
To avoid these issues, perform an indirect call via a read-only memory
location containing the address.
This solution is not perfect, as it assumes that the .rodata section
is laid out within 2^31 bytes of each function body, but this seems to
be sufficient for JIT.
Differential Revision: http://reviews.llvm.org/D6787
llvm-svn: 225003
It is intended to be used for a family of personality functions that
have similar IR preparation requirements. Typically when interoperating
with MSVC personality functions, bits of functionality need to be
outlined from the main function into helper functions. There is also
usually more than one landing pad per invoke, which does not match the
LLVM IR landingpad representation.
None of this is implemented yet. This change just adds a new enum that
is active for *-windows-msvc and delegates to the EH removal preparation
pass. No functionality change for other targets.
llvm-svn: 224625
This handles the simplest case for mov -> push conversion:
1. x86-32 calling convention, everything is passed through the stack.
2. There is no reserved call frame.
3. Only registers or immediates are pushed, no attempt to combine a mem-reg-mem sequence into a single PUSHmm.
Differential Revision: http://reviews.llvm.org/D6503
llvm-svn: 223757
Commit on
- This patch fixes the bug described in
http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-May/062343.html
The fix allocates an extra slot just below the GPRs and stores the base pointer
there. This is done only for functions containing llvm.eh.sjlj.setjmp that also
need a base pointer. Because code containing llvm.eh.sjlj.setjmp saves all of
the callee-save GPRs in the prologue, the offset to the extra slot can be
computed before prologue generation runs.
Impact at run-time on affected functions is::
- One extra store in the prologue, The store saves the base pointer.
- One extra load after a llvm.eh.sjlj.setjmp. The load restores the base pointer.
Because the extra slot is just above a gap between frame-pointer-relative and
base-pointer-relative chunks of memory, there is no impact on other offset
calculations other than ensuring there is room for the extra slot.
http://reviews.llvm.org/D6388
Patch by Arch Robison <arch.robison@intel.com>
llvm-svn: 223329
This is the second patch in a small series. This patch contains the MachineInstruction and x86-64 backend pieces required to lower Statepoints. It does not include the code to actually generate the STATEPOINT machine instruction and as a result, the entire patch is currently dead code. I will be submitting the SelectionDAG parts within the next 24-48 hours. Since those pieces are by far the most complicated, I wanted to minimize the size of that patch. That patch will include the tests which exercise the functionality in this patch. The entire series can be seen as one combined whole in http://reviews.llvm.org/D5683.
The STATEPOINT psuedo node is generated after all gc values are explicitly spilled to stack slots. The purpose of this node is to wrap an actual call instruction while recording the spill locations of the meta arguments used for garbage collection and other purposes. The STATEPOINT is modeled as modifing all of those locations to prevent backend optimizations from forwarding the value from before the STATEPOINT to after the STATEPOINT. (Doing so would break relocation semantics for collectors which wish to relocate roots.)
The implementation of STATEPOINT is closely modeled on PATCHPOINT. Eventually, much of the code in this patch will be removed. The long term plan is to merge the functionality provided by statepoints and patchpoints. Merging their implementations in the backend is likely to be a good starting point.
Reviewed by: atrick, ributzka
llvm-svn: 223085
Summary:
The current "WinEH" exception handling type is more about Itanium-style
LSDA tables layered on top of the Windows native unwind info format
instead of .eh_frame tables or EHABI unwind info. Use the name
"ItaniumWinEH" to better reflect the hybrid nature of the design.
Also rename isExceptionHandlingDWARF to usesItaniumLSDAForExceptions,
since the LSDA is part of the Itanium C++ ABI document, and not the
DWARF standard.
Reviewers: echristo
Subscribers: llvm-commits, compnerd
Differential Revision: http://reviews.llvm.org/D6279
llvm-svn: 222062
This is dangerous for numerous reasons. The primary risk here is with
floating point or double types where if the wrong header files are
included in a strange order this can implicitly convert to integers and
then call the C abs function on the integers. There is a secondary risk
that even impacts integers where if the namespace the code is written in
ever defines an abs overload for types within that namespace the global
abs will be hidden. The correct form is to call std::abs or write 'using
std::abs' for builtin types (and only the latter is correct in any
generic context).
I've also added the requisite header to be a bit more explicit here.
llvm-svn: 219484
Do not eliminate the frame pointer if there is a stackmap or patchpoint in the
function. All stackmap references should be FP relative.
This fixes PR21107.
llvm-svn: 218920
Summary:
Update segmented-stacks*.ll tests with x32 target case and make
corresponding changes to make them pass.
Test Plan: tests updated with x32 target
Reviewers: nadav, rafael, dschuff
Subscribers: llvm-commits, zinovy.nis
Differential Revision: http://reviews.llvm.org/D5245
llvm-svn: 218247
Summary:
Since pointers are 32-bit on x32 we can use ebp and esp as frame and stack
pointer. Some operations like PUSH/POP and CFI_INSTRUCTION still
require 64-bit register, so using 64-bit MachineFramePtr where required.
X86_64 NaCl uses 64-bit frame/stack pointers, however it's been found that
both isTarget64BitLP64 and isTarget64BitILP32 are true for NaCl. Addressing
this issue here as well by making isTarget64BitLP64 false.
Also mark hasReservedSpillSlot unreachable on X86. See inlined comments.
Test Plan: Add one new simple test and upgrade 2 existing with x32 target case.
Reviewers: nadav, dschuff
Subscribers: llvm-commits, zinovy.nis
Differential Revision: http://reviews.llvm.org/D4617
llvm-svn: 215091
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.
Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.
llvm-svn: 214838
When the last instruction prior to a function epilogue is a call, we
need to emit a nop so that the return address is not in the epilogue IP
range. This is consistent with MSVC's behavior, and may be a workaround
for a bug in the Win64 unwinder.
Differential Revision: http://reviews.llvm.org/D4751
Patch by Vadim Chugunov!
llvm-svn: 214775
seh_stackalloc 0 is not representable in Win64 SEH info, so emitting it
is a bug.
Reviewers: rnk
Differential Revision: http://reviews.llvm.org/D4334
Patch by Vadim Chugunov!
llvm-svn: 212081
This exception format is not specific to Windows x64. A similar approach is
taken on nearly all architectures. Generalise the name to reflect reality.
This will eventually be used for Windows on ARM data emission as well.
Switch the enum and namespace into an enum class.
llvm-svn: 212000
--
This patch enables LLVM to emit Win64-native unwind info rather than
DWARF CFI. It handles all corner cases (I hope), including stack
realignment.
Because the unwind info is not flexible enough to describe stack frames
with a gap of unknown size in the middle, such as the one caused by
stack realignment, I modified register spilling code to place all spills
into the fixed frame slots, so that they can be accessed relative to the
frame pointer.
Patch by Vadim Chugunov!
Reviewed By: rnk
Differential Revision: http://reviews.llvm.org/D4081
llvm-svn: 211691
This patch enables LLVM to emit Win64-native unwind info rather than
DWARF CFI. It handles all corner cases (I hope), including stack
realignment.
Because the unwind info is not flexible enough to describe stack frames
with a gap of unknown size in the middle, such as the one caused by
stack realignment, I modified register spilling code to place all spills
into the fixed frame slots, so that they can be accessed relative to the
frame pointer.
Patch by Vadim Chugunov!
Reviewed By: rnk
Differential Revision: http://reviews.llvm.org/D4081
llvm-svn: 211399
This removes the -segmented-stacks command line flag in favor of a
per-function "split-stack" attribute.
Patch by Luqman Aden and Alex Crichton!
llvm-svn: 205997
Identical to Win32 method except the GS segment register is used for TLS
instead of FS and pvArbitrary is at TEB offset 0x28 instead of 0x14.
llvm-svn: 205342
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&. At this point they almost behave like normal iterators!
Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.
llvm-svn: 203865
The old system was fairly convoluted:
* A temporary label was created.
* A single PROLOG_LABEL was created with it.
* A few MCCFIInstructions were created with the same label.
The semantics were that the cfi instructions were mapped to the PROLOG_LABEL
via the temporary label. The output position was that of the PROLOG_LABEL.
The temporary label itself was used only for doing the mapping.
The new CFI_INSTRUCTION has a 1:1 mapping to MCCFIInstructions and points to
one by holding an index into the CFI instructions of this function.
I did consider removing MMI.getFrameInstructions completelly and having
CFI_INSTRUCTION own a MCCFIInstruction, but MCCFIInstructions have non
trivial constructors and destructors and are somewhat big, so the this setup
is probably better.
The net result is that we don't create temporary labels that are never used.
llvm-svn: 203204
This finishes the job started in r198756, and creates separate opcodes for
64-bit vs. 32-bit versions of the rest of the RET instructions too.
LRETL/LRETQ are interesting... I can't see any justification for their
existence in the SDM. There should be no 'LRETL' in 64-bit mode, and no
need for a REX.W prefix for LRETQ. But this is what GAS does, and my
Sandybridge CPU and an Opteron 6376 concur when tested as follows:
asm __volatile__("pushq $0x1234\nmovq $0x33,%rax\nsalq $32,%rax\norq $1f,%rax\npushq %rax\nlretl $8\n1:");
asm __volatile__("pushq $1234\npushq $0x33\npushq $1f\nlretq $8\n1:");
asm __volatile__("pushq $0x33\npushq $1f\nlretq\n1:");
asm __volatile__("pushq $0x1234\npushq $0x33\npushq $1f\nlretq $8\n1:");
cf. PR8592 and commit r118903, which added LRETQ. I only added LRETIQ to
match it.
I don't quite understand how the Intel syntax parsing for ret
instructions is working, despite r154468 allegedly fixing it. Aren't the
explicitly sized 'retw', 'retd' and 'retq' supposed to work? I have at
least made the 'lretq' work with (and indeed *require*) the 'q'.
llvm-svn: 199106
I couldn't see how to do this sanely without splitting RETQ from RETL.
Eric says: "sad about the inability to roundtrip them now, but...".
I have no idea what that means, but perhaps it wants preserving in the
commit comment.
llvm-svn: 198756
Since gcc 4.6 the compiler uses ___chkstk_ms which has the same semantics as the
MS CRT function __chkstk. This simplifies the prologue generation a bit.
Reviewed by Rafael Espíndola.
llvm-svn: 197205
This re-lands commit r196876, which was reverted in r196879.
The tests have been fixed to pass on platforms with a stack alignment
larger than 4.
Update to clang side tests will land shortly.
llvm-svn: 196939
Most users would be surprised if "isCOFF" and "isMachO" were simultaneously
true, unless they'd put the compiler in a box with a gun attached to a photon
detector.
This makes sure precisely one of the three formats is true for any triple and
simplifies some target logic based on that.
llvm-svn: 196934
