This could actually be implemented with the LLVM IR va_arg instruction,
but it doesn't seem to offer any advantages over accessing the va_list
pointer directly.
Using the va_list pointer directly makes it possible to perform type
coercion directly from the argument array, and the va_list updates are
exposed to the optimizers.
llvm-svn: 183292
The coercion type serves two purposes:
1. Pad structs to a multiple of 64 bits, so they are passed
'left-aligned' in registers.
2. Expose aligned floating point elements as first-level elements, so
the code generator knows to pass them in floating point registers.
We also compute the InReg flag which indicates that the struct contains
aligned 32-bit floats. This flag is used by the code generator to pick
the right registers.
llvm-svn: 182753
- All integer arguments smaller than 64 bits are extended.
- Large structs are passed indirectly, not using 'byval'.
- Structs up to 32 bytes in size are returned in registers.
Some things are not implemented yet:
- EmitVAArg can be implemented in terms of the va_arg instruction.
- When structs are passed in registers, float members require special
handling because they are passed in the floating point registers.
- Structs are left-aligned when passed in registers. This may require
padding.
llvm-svn: 182745
Summary:
Most of this change is wiring the pragma all the way through from the
lexer, parser, and sema to codegen. I considered adding a Decl AST node
for this, but it seemed too heavyweight.
Mach-O already uses a metadata flag called "Linker Options" to do this
kind of auto-linking. This change follows that pattern.
LLVM knows how to forward the "Linker Options" metadata into the COFF
.drectve section where these flags belong. ELF support is not
implemented, but possible.
This is related to auto-linking, which is http://llvm.org/PR13016.
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D723
llvm-svn: 181426
This patch then adds all the usual platform-specific pieces for SystemZ:
driver support, basic target info, register names and constraints,
ABI info and vararg support. It also adds new tests to verify pre-defined
macros and inline asm, and updates a test for the minimum alignment change.
This version of the patch incorporates feedback from reviews by
Eric Christopher and John McCall. Thanks to all reviewers!
Patch by Richard Sandiford.
llvm-svn: 181211
Also,
- abstract out the indirect/in memory/in registers decisions into the CGCXXABI
- fix handling of empty struct arguments for '-cxx-abi microsoft'
- add/fix tests
llvm-svn: 179681
If this should not happen, we should have an assert.
If it should happen, we should have a test and remove the comment.
In no case should we have this self inconsistent code.
llvm-svn: 177399
I have filed http://llvm.org/bugs/show_bug.cgi?id=15538 against clang.
This code is safer anyway because "cast" assumes you really know that
it's okay to make the cast. In this case isa should not be false and
dyn_cast should not return null as far as I understand. But everything
else is valid so I did not want to revert my previous patch for attributes
mips16/nomips16 or use an llvm_unreachable here which would make a number
of our tests fail for mips.
llvm-svn: 177329
aggregate types in a profoundly wrong way that has to be
worked around in every call site, to getEvaluationKind,
which classifies and distinguishes between all of these
cases.
Also, normalize the API for loading and storing complexes.
I'm working on a larger patch and wanted to pull these
changes out, but it would have be annoying to detangle
them from each other.
llvm-svn: 176656
calls and declarations.
LLVM has a default CC determined by the target triple. This is
not always the actual default CC for the ABI we've been asked to
target, and so we sometimes find ourselves annotating all user
functions with an explicit calling convention. Since these
calling conventions usually agree for the simple set of argument
types passed to most runtime functions, using the LLVM-default CC
in principle has no effect. However, the LLVM optimizer goes
into histrionics if it sees this kind of formal CC mismatch,
since it has no concept of CC compatibility. Therefore, if this
module happens to define the "runtime" function, or got LTO'ed
with such a definition, we can miscompile; so it's quite
important to get this right.
Defining runtime functions locally is quite common in embedded
applications.
llvm-svn: 176286
In cooperation with the LLVM patch, this should implement all scalar front-end
parts of the C and C++ ABIs for AArch64.
This patch excludes the NEON support also reviewed due to an outbreak of
batshit insanity in our legal department. That will be committed soon bringing
the changes to precisely what has been approved.
Further reviews would be gratefully received.
llvm-svn: 174055
the 64-bit PowerPC ELF ABI.
The ABI requires that the real and imaginary parts of a complex argument
each occupy their own doubleword. Arguments smaller than 8 bytes are
right-adjusted within the doubleword.
Clang expects EmitVAARG() to return a pointer to a structure in which
the real and imaginary parts are packed adjacently in memory. To accomplish
this, we generate code to load the code appropriately from the varargs
location and pack the values into a temporary variable in the form Clang
expects, returning a pointer to that structure.
The test case demonstrates correct code generation for all "small" complex
types on PPC64: int, short, char, and float.
llvm-svn: 172438
incompatibility with how complex values are returned. It is sufficient
to flag all complex types as direct rather than indirect.
A new test case is provided that checks correct IR generation for the
various supported flavors of _Complex.
llvm-svn: 170302
uncovered.
This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.
I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.
llvm-svn: 169237
ELF ABI.
Complex values are to be passed in registers as though the real and
imaginary parts were passed as separate parameters. Prior to this
patch, complex values were passed as byval aggregates. It turns out
that specifying getDirect() for all complex types when classifying the
argument type results in the desired behavior.
The new Clang test case verifies that the correct LLVM IR is generated
for caller and callee for each of the underlying types for _Complex.
llvm-svn: 168673
Separate out the notions of 'has a trivial special member' and 'has a
non-trivial special member', and use them appropriately. These are not
opposites of one another (there might be no special member, or in C++11 there
might be a trivial one and a non-trivial one). The CXXRecordDecl predicates
continue to produce incorrect results, but do so in fewer cases now, and
they document the cases where they might be wrong.
No functionality changes are intended here (they will come when the predicates
start producing the right answers...).
llvm-svn: 168119
disabling byval, we set realign to true.
It will perform an aligned alloca, and call memcpy to copy the byval
argument to the local variable.
Change the size threshold back to 64 bytes.
rdar://12596507
llvm-svn: 167440
the type alignment of the byval argument. This patch will disable byval in this case,
it also increases the size threshold for turning on byval.
A backend fix will be attempted.
rdar://12596507
llvm-svn: 167416
zero-extended to 64 bits. This information is currently provided to
the back end by setting "signext" or "zeroext" attributes. However,
this is done only for integer types *smaller* than i32, not for i32
itself. This causes clang to generate code violating the ABI, which
results in a failure of the tramp3d-v4 test case (due to calling a
system library routine without ABI-required extension).
This patch implements custom versions of classifyArgumentType and
classifyReturnType for PPC64_SVR4_ABIInfo, which are the same as the
default versions except that they also classify "int" and "unsigned int"
as types needing extending. This fixed tramp3d-v4 on PowerPC64.
llvm-svn: 167393
If HA can only partially fit into VFP registers, we add padding to make sure
HA will be on stack and later VFP CPRCs will be on stack as well.
llvm-svn: 167058
varargs parameter passing.
A strict reading of the ABI indicates that any argument with alignment greater
than 8 may require skipping doublewords in the parameter save area to align
the argument, and hence require skipping GPRs. In practice, this is not done
by GCC. The alignment restriction is used for internal alignment of a
structure, but a structure with 16-byte alignment, for example, is not
itself 16-byte aligned in the parameter save area. Although this is messy,
it has become the de facto standard used in building existing libraries.
My initial varargs support followed the ABI language, but not the de facto
standard. Running the GCC compatibility test suite exposed this issue, and
indeed showed that LLVM didn't pass parameters self-consistently with my
original logic. Removing the additional alignment logic allows the affected
tests to now pass.
I modified the ppc64-varargs-struct.c test case to remove the existing test
for generation of alignment code, which is no longer appropriate.
Built and tested on powerpc64-unknown-linux-gnu with no new regressions.
llvm-svn: 166805
constructors.
When I first moved regparm support to TargetInfo.cpp I tried to isolate it
in classifyArgumentTypeWithReg, but it is actually a lot easier to flip the
code around and check for regparm at the end of the decision tree.
Without this refactoring classifyArgumentTypeWithReg would have to duplicate
the logic about when to use non-byval indirect arguments.
llvm-svn: 166266
Because PNaCl bitcode must be target-independent, it uses some
different bitcode representations from other targets (e.g. byval and
sret for structures). This means that without additional type
information, it cannot meet some native ABI requirements for some
targets (e.g. passing structures containing unions by value on
x86-64). To allow generation of code which uses the correct native
ABIs, we also support triples such as x86_64-nacl, which uses
target-dependent IR (as opposed to le32-nacl, which uses byval and
sret).
To allow interoperation between the two types of code, this patch adds
a calling convention attribute to be used in code compiled with the
target-dependent triple, which will generate code using the le32-style
bitcode. This calling convention does not need to be explicitly
supported in the backend because it determines bitcode representation
rather than native conventions (the backend just needs to undersand
how to handle byval and sret for the Native Client OS).
This patch implements __attribute__((pnaclcall)) to generate calls in
bitcode according to the le32 bitcode conventions, an attribute which
is accepted by any Native Client target, but issues a warning
otherwise.
llvm-svn: 166065
Jakob Stoklund Olesen