This patch introduces a new pass that computes the safe point to insert the
prologue and epilogue of the function.
The interest is to find safe points that are cheaper than the entry and exits
blocks.
As an example and to avoid regressions to be introduce, this patch also
implements the required bits to enable the shrink-wrapping pass for AArch64.
** Context **
Currently we insert the prologue and epilogue of the method/function in the
entry and exits blocks. Although this is correct, we can do a better job when
those are not immediately required and insert them at less frequently executed
places.
The job of the shrink-wrapping pass is to identify such places.
** Motivating example **
Let us consider the following function that perform a call only in one branch of
a if:
define i32 @f(i32 %a, i32 %b) {
%tmp = alloca i32, align 4
%tmp2 = icmp slt i32 %a, %b
br i1 %tmp2, label %true, label %false
true:
store i32 %a, i32* %tmp, align 4
%tmp4 = call i32 @doSomething(i32 0, i32* %tmp)
br label %false
false:
%tmp.0 = phi i32 [ %tmp4, %true ], [ %a, %0 ]
ret i32 %tmp.0
}
On AArch64 this code generates (removing the cfi directives to ease
readabilities):
_f: ; @f
; BB#0:
stp x29, x30, [sp, #-16]!
mov x29, sp
sub sp, sp, #16 ; =16
cmp w0, w1
b.ge LBB0_2
; BB#1: ; %true
stur w0, [x29, #-4]
sub x1, x29, #4 ; =4
mov w0, wzr
bl _doSomething
LBB0_2: ; %false
mov sp, x29
ldp x29, x30, [sp], #16
ret
With shrink-wrapping we could generate:
_f: ; @f
; BB#0:
cmp w0, w1
b.ge LBB0_2
; BB#1: ; %true
stp x29, x30, [sp, #-16]!
mov x29, sp
sub sp, sp, #16 ; =16
stur w0, [x29, #-4]
sub x1, x29, #4 ; =4
mov w0, wzr
bl _doSomething
add sp, x29, #16 ; =16
ldp x29, x30, [sp], #16
LBB0_2: ; %false
ret
Therefore, we would pay the overhead of setting up/destroying the frame only if
we actually do the call.
** Proposed Solution **
This patch introduces a new machine pass that perform the shrink-wrapping
analysis (See the comments at the beginning of ShrinkWrap.cpp for more details).
It then stores the safe save and restore point into the MachineFrameInfo
attached to the MachineFunction.
This information is then used by the PrologEpilogInserter (PEI) to place the
related code at the right place. This pass runs right before the PEI.
Unlike the original paper of Chow from PLDI’88, this implementation of
shrink-wrapping does not use expensive data-flow analysis and does not need hack
to properly avoid frequently executed point. Instead, it relies on dominance and
loop properties.
The pass is off by default and each target can opt-in by setting the
EnableShrinkWrap boolean to true in their derived class of TargetPassConfig.
This setting can also be overwritten on the command line by using
-enable-shrink-wrap.
Before you try out the pass for your target, make sure you properly fix your
emitProlog/emitEpilog/adjustForXXX method to cope with basic blocks that are not
necessarily the entry block.
** Design Decisions **
1. ShrinkWrap is its own pass right now. It could frankly be merged into PEI but
for debugging and clarity I thought it was best to have its own file.
2. Right now, we only support one save point and one restore point. At some
point we can expand this to several save point and restore point, the impacted
component would then be:
- The pass itself: New algorithm needed.
- MachineFrameInfo: Hold a list or set of Save/Restore point instead of one
pointer.
- PEI: Should loop over the save point and restore point.
Anyhow, at least for this first iteration, I do not believe this is interesting
to support the complex cases. We should revisit that when we motivating
examples.
Differential Revision: http://reviews.llvm.org/D9210
<rdar://problem/3201744>
llvm-svn: 236507
Summary:
Until now, we did this (among other things) based on whether or not the
target was Windows. This is clearly wrong, not just for Win64 ABI functions
on non-Windows, but for System V ABI functions on Windows, too. In this
change, we make this decision based on the ABI the calling convention
specifies instead.
Reviewers: rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D7953
llvm-svn: 230793
The Win64 epilogue structure is very restrictive, it permits a very
small number of opcodes and none of them are 'mov'.
This means that given:
mov %rbp, %rsp
pop %rbp
The mov isn't the epilogue, only the pop is. This is problematic unless
a frame pointer is present in which case we are free to do whatever we'd
like in the "body" of the function. If a frame pointer is present,
unwinding will undo the prologue operations in reverse order regardless
of the fact that we are at an instruction which is reseting the stack
pointer.
llvm-svn: 230543
Prologue emission, in some cases, requires calls to a stack probe helper
function. The amount of stack to probe is passed as a register
argument in the Win64 ABI but the instruction sequence used is
pessimistic: it assumes that the number of bytes to probe is greater
than 4 GB.
Instead, select a more appropriate opcode depending on the number of
bytes we are going to probe.
llvm-svn: 230270
Stack realignment occurs after the prolog, not during, for Win64.
Because of this, don't factor in the maximum stack alignment when
establishing a frame pointer.
This fixes PR22572.
llvm-svn: 230113
Canonicalize access to function attributes to use the simpler API.
getAttributes().getAttribute(AttributeSet::FunctionIndex, Kind)
=> getFnAttribute(Kind)
getAttributes().hasAttribute(AttributeSet::FunctionIndex, Kind)
=> hasFnAttribute(Kind)
llvm-svn: 229214
Simply loading or storing the frame pointer is not sufficient for
Windows targets. Instead, create a synthetic frame object that we will
lower later. References to this synthetic object will be replaced with
the correct reference to the frame address.
llvm-svn: 228748
Walk the instructions marked FrameSetup and consider any stores of XMM
registers to the stack as needing a SaveXMM opcode.
This fixes PR22521.
Differential Revision: http://reviews.llvm.org/D7527
llvm-svn: 228724
Win64 has specific contraints on what valid prologues and epilogues look
like. This constraint is born from the flexibility and descriptiveness
of Win64's unwind opcodes.
Prologues previously emitted by LLVM could not be represented by the
unwind opcodes, preventing operations powered by stack unwinding to
successfully work.
Differential Revision: http://reviews.llvm.org/D7520
llvm-svn: 228641
This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a
reserved call frame), and perform rudimentary call folding. It still doesn't
have a heuristic, so it is enabled only for optsize/minsize, with stack
alignment <= 8, where it ought to be a fairly clear win.
(Re-commit of r227728)
Differential Revision: http://reviews.llvm.org/D6789
llvm-svn: 227752
This moves the transformation introduced in r223757 into a separate MI pass.
This allows it to cover many more cases (not only cases where there must be a
reserved call frame), and perform rudimentary call folding. It still doesn't
have a heuristic, so it is enabled only for optsize/minsize, with stack
alignment <= 8, where it ought to be a fairly clear win.
Differential Revision: http://reviews.llvm.org/D6789
llvm-svn: 227728
MSDN's x64 software conventions page says that this is one of the fixed
list of legal epilogues:
https://msdn.microsoft.com/en-us/library/tawsa7cb.aspx
Presumably this is how the unwinder distinguishes epilogue jumps from
in-function control flow.
Also normalize the way we place "## TAILCALL" comments on such jumps.
llvm-svn: 227611
In the large code model, we now put __chkstk in %r11 before calling it.
Refactor the code so that we only do this once. Simplify things by using
__chkstk_ms instead of __chkstk on cygming. We already use that symbol
in the prolog emission, and it simplifies our logic.
Second half of PR18582.
llvm-svn: 227519
win64: Call __chkstk through a register with the large code model
Fixes half of PR18582. True dynamic allocas will still have a
CALL64pcrel32 which will fail.
Reviewers: majnemer
Differential Revision: http://reviews.llvm.org/D7267
llvm-svn: 227503
For large stack offsets the compiler generates multiple immediate mode
sub/add instructions in the prologue/epilogue. This patch makes the
compiler place the final amount to be added/subtracted into a register,
which is then added/substracted with a single operation.
Differential Revision: http://reviews.llvm.org/D7226
llvm-svn: 227458
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
For stack frames requiring realignment, three pointers may be needed:
- ebp to address incoming arguments
- esi (could be any callee-saved register) to address locals
- esp to address outgoing arguments
We would use esi unconditionally without verifying that it did not
conflict with inline assembly.
This change doesn't do the verification, it simply emits a fatal error
on functions that use stack realignment, dynamic SP adjustments, and
inline assembly.
Because stack realignment is common on Windows, we also no longer assume
that MS inline assembly clobbers esp. Instead, we analyze the inline
instructions for implicit definitions and check if esp is there. If so,
we require the use of a base pointer and consider it in the condition
above.
Mostly fixes PR16830, but we could try harder to find a non-conflicting
base pointer.
Reviewers: sunfish
Differential Revision: http://llvm-reviews.chandlerc.com/D1317
llvm-svn: 196876
Calling _chkstk is required on ELF as well as COFF on Windows. Without
_chkstk, functions requiring large stack crash in initialization code.
Previous code tested for COFF format but not Mach-O and this patch modifies
the code to test for Windows OS (both Windows target and MingW target)
but not Mach-O object format: Looks like macho environment was used to
build some EFI code.
Credits to Andrew MacPherson.
llvm-svn: 193289
Without _chkstk functions requiring large stack crash in
initialization code. Previous code tested for COFF format but
not Mach-O and this patch modifies the code to test for Windows.
Credits to Andrew MacPherson.
llvm-svn: 193263
We used to generate the compact unwind encoding from the machine
instructions. However, this had the problem that if the user used `-save-temps'
or compiled their hand-written `.s' file (with CFI directives), we wouldn't
generate the compact unwind encoding.
Move the algorithm that generates the compact unwind encoding into the
MCAsmBackend. This way we can generate the encoding whether the code is from a
`.ll' or `.s' file.
<rdar://problem/13623355>
llvm-svn: 190290
Due to the weird and wondeful usual arithmetic conversions, some
calculations involving negative values were getting performed in
uint32_t and then promoted to int64_t, which is really not a good
idea.
Patch by Katsuhiro Ueno.
llvm-svn: 187703
We generate a `push' of a random register (%rax) if the stack needs to be
aligned by the size of that register. However, this could mess up compact unwind
generation. In particular, we want to still generate compact unwind in the
presence of this monstrosity.
Check if the push of of the %rax/%eax register. If it is and it's marked with
the `FrameSetup' flag, then we can generate a compact unwind encoding for the
function only if the push is the last FrameSetup instruction.
llvm-svn: 181540
The compact unwind registers were defined in two different
places. It's better just to place them in the function that uses them
and specify that this is a 64-bit or 32-bit machine.
No functionality change.
llvm-svn: 181529
to TargetFrameLowering, where it belongs. Incidentally, this allows us
to delete some duplicated (and slightly different!) code in TRI.
There are potentially other layering problems that can be cleaned up
as a result, or in a similar manner.
The refactoring was OK'd by Anton Korobeynikov on llvmdev.
Note: this touches the target interfaces, so out-of-tree targets may
be affected.
llvm-svn: 175788
If the frame pointer is omitted, and any stack changes occur in the inline
assembly, e.g.: "pusha", then any C local variable or C argument references
will be incorrect.
I pass no judgement on anyone who would do such a thing. ;)
rdar://13218191
llvm-svn: 175334
account. Atoms use LEA for updating SP in prologs/epilogs, and the
exact LEA opcode depends on the data model.
Also reapplying the test case which was added and then reverted
(because of Atom failures), this time specifying explicitly the CPU in
addition to the triple. The test case now checks all variations (data
mode, cpu Atom vs. Core).
llvm-svn: 174542
pointer in function prologs/epilogs. The opcodes should depend on the
data model (LP64 vs. ILP32) rather than the architecture bit-ness.
llvm-svn: 174446
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
llvm-svn: 171366
directly.
This is in preparation for removing the use of the 'Attribute' class as a
collection of attributes. That will shift to the AttributeSet class instead.
llvm-svn: 171253
The only way to read the eflags is using push and pop. If we don't
adjust the stack then we run over the first frame index. This is
not something that we want to do, so we have to make sure that
our machine function does not copy the flags. If it does then
we have to emit the prolog that adjusts the stack.
rdar://12896831
llvm-svn: 170961
This function is often used to decorate dangling instructions, so a
context reference is required to allocate memory for the operands.
Also add a corresponding MachineInstrBuilder method.
llvm-svn: 170797
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. =]
llvm-svn: 169131
We use the enums to query whether an Attributes object has that attribute. The
opaque layer is responsible for knowing where that specific attribute is stored.
llvm-svn: 165488
a) frame setup instructions define the prologue
b) we shouldn't change our location mid-stream
Add a test to make sure that the stack adjustment stays within
the prologue.
llvm-svn: 165250
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
X86MachineFunctionInfo as this is currently only used by X86. If this ever
becomes an issue on another arch (e.g., ARM) then we can hoist it back out.
llvm-svn: 160009
X86. Basically, this is a reapplication of r158087 with a few fixes.
Specifically, (1) the stack pointer is restored from the base pointer before
popping callee-saved registers and (2) in obscure cases (see comments in patch)
we must cache the value of the original stack adjustment in the prologue and
apply it in the epilogue.
rdar://11496434
llvm-svn: 160002
The code in X86TargetLowering::LowerEH_RETURN() assumes that a frame
pointer exists, but the frame pointer was forced by the presence of
llvm.eh.unwind.init which isn't guaranteed.
If llvm.eh.unwind.init is actually required in functions calling
eh.return (is it?), we should diagnose that instead of emitting bad
machine code.
This should fix the dragonegg-x86_64-linux-gcc-4.6-test bot.
llvm-svn: 158961
This patch causes problems when both dynamic stack realignment and
dynamic allocas combine in the same function. With this patch, we no
longer build the epilog correctly, and silently restore registers from
the wrong position in the stack.
Thanks to Matt for tracking this down, and getting at least an initial
test case to Chad. I'm going to try to check a variation of that test
case in so we can easily track the fixes required.
llvm-svn: 158654
No functional change intended.
Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.
This makes it possible to do so without changing all clients (again).
llvm-svn: 157854
The registers are placed into the saved registers list in the reverse order,
which is why the original loop was written to loop backwards.
llvm-svn: 148064
Restore the (obviously wrong) behavior from before r147938 without relying on
undefined behavior. Add a fat FIXME note.
This should fix nightly tester failures.
llvm-svn: 148030
the compact unwind claiming that one register was saved before another, which
isn't all that great in general. Process them in the natural order. Reverse the
list only when necessary for the algorithm.
llvm-svn: 146612
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.
For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.
llvm-svn: 146026
libgcc sets the stack limit field in TCB to 256 bytes above the actual
allocated stack limit. This means if the function's stack frame needs
less than 256 bytes, we can just compare the stack pointer with the
stack limit. This should result in lesser calls to __morestack.
llvm-svn: 145766
Currently LLVM pads the call to __morestack with a add and sub of 8
bytes to esp. This isn't correct since __morestack expects the call
to be followed directly by a ret.
This commit also adjusts the relevant test-case.
llvm-svn: 145765
change, now you need a TargetOptions object to create a TargetMachine. Clang
patch to follow.
One small functionality change in PTX. PTX had commented out the machine
verifier parts in their copy of printAndVerify. That now calls the version in
LLVMTargetMachine. Users of PTX who need verification disabled should rely on
not passing the command-line flag to enable it.
llvm-svn: 145714
MORESTACK_RET_RESTORE_R10; which are lowered to a RET and a RET
followed by a MOV respectively. Having a fake instruction prevents
the verifier from seeing a MachineBasicBlock end with a
non-terminator (MOV). It also prevents the rather eccentric case of a
MachineBasicBlock ending with RET but having successors nevertheless.
Patch by Sanjoy Das.
llvm-svn: 143062
X86. Modify the pass added in the previous patch to call this new
code.
This new prologues generated will call a libgcc routine (__morestack)
to allocate more stack space from the heap when required
Patch by Sanjoy Das.
llvm-svn: 138812
unwind encoding for that function. This simply crawls through the prolog looking
for machine instrs marked as "frame setup". It can calculate from these what the
compact unwind should look like.
This is currently disabled because of needed linker support. But initial tests
look good.
llvm-svn: 135922
Quentin Colombet