Mips16 is really a processor decoding mode (ala thumb 1) and in the same
program, mips16 and mips32 functions can exist and can call each other.
If a jal type instruction encounters an address with the lower bit set, then
the processor switches to mips16 mode (if it is not already in it). If the
lower bit is not set, then it switches to mips32 mode.
The linker knows which functions are mips16 and which are mips32.
When relocation is performed on code labels, this lower order bit is
set if the code label is a mips16 code label.
In general this works just fine, however when creating exception handling
tables and dwarf, there are cases where you don't want this lower order
bit added in.
This has been traditionally distinguished in gas assembly source by using a
different syntax for the label.
lab1: ; this will cause the lower order bit to be added
lab2=. ; this will not cause the lower order bit to be added
In some cases, it does not matter because in dwarf and debug tables
the difference of two labels is used and in that case the lower order
bits subtract each other out.
To fix this, I have added to mcstreamer the notion of a debuglabel.
The default is for label and debug label to be the same. So calling
EmitLabel and EmitDebugLabel produce the same result.
For various reasons, there is only one set of labels that needs to be
modified for the mips exceptions to work. These are the "$eh_func_beginXXX"
labels.
Mips overrides the debug label suffix from ":" to "=." .
This initial patch fixes exceptions. More changes most likely
will be needed to DwarfCFException to make all of this work
for actual debugging. These changes will be to emit debug labels in some
places where a simple label is emitted now.
Some historical discussion on this from gcc can be found at:
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00623.htmlhttp://gcc.gnu.org/ml/gcc-patches/2008-11/msg01273.html
llvm-svn: 170279
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
to support it. Original patch with the parsing and plumbing by the PaX team and
Roman Divacky. I added the bits in MCDwarf.cpp and the test.
llvm-svn: 168565
For some reason .lcomm uses byte alignment and .comm log2 alignment so we can't
use the same setting for both. Fix this by reintroducing the LCOMM enum.
I verified this against mingw's gcc.
llvm-svn: 163420
- Darwin lied about not supporting .lcomm and turned it into zerofill in the
asm parser. Push the zerofill-conversion down into macho-specific code.
- This makes the tri-state LCOMMType enum superfluous, there are no targets
without .lcomm.
- Do proper error reporting when trying to use .lcomm with alignment on a target
that doesn't support it.
- .comm and .lcomm alignment was parsed in bytes on COFF, should be power of 2.
- Fixes PR13755 (.lcomm crashes on ELF).
llvm-svn: 163395
Use a dedicated MachO load command to annotate data-in-code regions.
This is the same format the linker produces for final executable images,
allowing consistency of representation and use of introspection tools
for both object and executable files.
Data-in-code regions are annotated via ".data_region"/".end_data_region"
directive pairs, with an optional region type.
data_region_directive := ".data_region" { region_type }
region_type := "jt8" | "jt16" | "jt32" | "jta32"
end_data_region_directive := ".end_data_region"
The previous handling of ARM-style "$d.*" labels was broken and has
been removed. Specifically, it didn't handle ARM vs. Thumb mode when
marking the end of the section.
rdar://11459456
llvm-svn: 157062
debug info for assembly files. We were already doing the right thing when
producing debug info for C/C++.
ELF linkers don't know dwarf, so they depend on these relocations to produce
valid dwarf output.
llvm-svn: 151655
needed to emit a 64-bit gp-relative relocation entry. Make changes necessary
for emitting jump tables which have entries with directive .gpdword. This patch
does not implement the parts needed for direct object emission or JIT.
llvm-svn: 149668
file error checking. Use that to error on an unfinished cfi_startproc.
The error is not nice, but is already better than a segmentation fault.
llvm-svn: 147717
generates the dwarf Compile Unit DIE and a dwarf subprogram DIE for each
non-temporary label.
The next part will be to get the clang driver to enable this when assembling
a .s file. rdar://9275556
llvm-svn: 146262
.file filenumber "directory" "filename"
This removes one join+split of the directory+filename in MC internals. Because
bitcode files have independent fields for directory and filenames in debug info,
this patch may change the .o files written by existing .bc files.
llvm-svn: 142300
- On COFF the .lcomm directive has an alignment argument.
- On ELF we fall back to .local + .comm
Based on a patch by NAKAMURA Takumi.
Fixes PR9337, PR9483 and PR10128.
llvm-svn: 138976
to MCRegisterInfo. Also initialize the mapping at construction time.
This patch eliminate TargetRegisterInfo from TargetAsmInfo. It's another step
towards fixing the layering violation.
llvm-svn: 135424
TargetAsmInfo, which in turn pulls in TargetRegisterInfo, etc. :-( There are
other cases of violations, but this is probably the worst.
This patch is but one small step towards fixing this. 500 more steps to go. :-(
llvm-svn: 135131
numbers should be printed instead of symbolic register names in
MCAsmStreamer::EmitRegisterName. This is necessary because some versions of
GNU assembler won't accept code in which symbolic register names are used in
cfi directives. There is no change in behavior unless the flag is explicitly
set to true by a backend.
llvm-svn: 134635
"Reinstate r133435 and r133449 (reverted in r133499) now that the clang
self-hosted build failure has been fixed (r133512)."
Due to some additional warnings.
llvm-svn: 133700
The LSDA is a bit difficult for the non-initiated to read. Even with comments,
it's not always clear what's going on. This wraps the ASM streamer in a class
that retains the LSDA and then emits a human-readable description of what's
going on in it.
So instead of having to make sense of:
Lexception1:
.byte 255
.byte 155
.byte 168
.space 1
.byte 3
.byte 26
Lset0 = Ltmp7-Leh_func_begin1
.long Lset0
Lset1 = Ltmp812-Ltmp7
.long Lset1
Lset2 = Ltmp913-Leh_func_begin1
.long Lset2
.byte 3
Lset3 = Ltmp812-Leh_func_begin1
.long Lset3
Lset4 = Leh_func_end1-Ltmp812
.long Lset4
.long 0
.byte 0
.byte 1
.byte 0
.byte 2
.byte 125
.long __ZTIi@GOTPCREL+4
.long __ZTIPKc@GOTPCREL+4
you can read this instead:
## Exception Handling Table: Lexception1
## @LPStart Encoding: omit
## @TType Encoding: indirect pcrel sdata4
## @TType Base: 40 bytes
## @CallSite Encoding: udata4
## @Action Table Size: 26 bytes
## Action 1:
## A throw between Ltmp7 and Ltmp812 jumps to Ltmp913 on an exception.
## For type(s): __ZTIi@GOTPCREL+4 __ZTIPKc@GOTPCREL+4
## Action 2:
## A throw between Ltmp812 and Leh_func_end1 does not have a landing pad.
llvm-svn: 133286
suffix (e.g. .xdata$myfunc). The suffix part isn't implemented yet, but
I'll get to it in the next patch.
Fix up all callers of the affected functions. Make them pass said suffix to
the function.
llvm-svn: 132205
them.
I had to add a special SwitchSectionNoChange method to MCStreamer just for
.seh_handlerdata. If this isn't OK, please let me know, and I'll find some
other way to fix .seh_handlerdata streaming.
llvm-svn: 132084
ours compatible with GAS.
In retrospect, I should have emailed binutils about this earlier. Thanks to
Kai Tietz for pointing out that GAS already had SEH directives.
llvm-svn: 131652
- StartChained and EndChained delimit a chained unwind area, which can contain
additional operations to be undone if an exception occurs inside of it.
- UnwindOnly declares that this function doesn't handle any exceptions. If it
has a handler, it's an unwind handler instead of an exception handler.
- Lsda declares the location and size of the LSDA, which in the Win64 EH
scheme is kept inside the UNWIND_INFO struct. Windows itself ignores the
LSDA; it's used by the Language-Specific Handler (the "Personality Function"
from DWARF).
llvm-svn: 131572
GAS has no such directives (not even mingw-w64 GAS has them), so I took
creative license with their names in assembly. I prefixed them all with
"w64_" to avoid namespace collisions, for example. If I discover that GAS
has taken a different approach, I'll change ours to match.
llvm-svn: 131525
("T is 1 if the target symbol S has type STT_FUNC and the
symbol addresses a Thumb instruction ;it is 0 otherwise."
from "ELF for the ARM Architecture" 4.7.1.2)
Patch by Koan-Sin Tan!
llvm-svn: 131406
for all symbol differences and can drop the old EmitPCRelSymbolValue
method.
This also make getExprForFDESymbol on ELF equal to the one on MachO, and it
can be made non-virtual.
llvm-svn: 130634
Currently the output should be almost identical to the one produced by CodeGen
to make the transition easier.
The only two differences I know of are:
* Some files get an extra advance loc of size 0. This will be fixed when
relaxations are enabled.
* The optimization of declaring an EH symbol as an external variable is not
implemented. This is a subset of adding the nounwind attribute, so we if really
this at -O0 we should probably do it at the IL level.
llvm-svn: 130623
foo = a - b
.long foo
instead of just
.long a - b
First, on darwin9 64 bits the assembler produces the wrong result. Second,
if "a" is the end of the section all darwin assemblers (9, 10 and mc) will not
consider a - b to be a constant but will if the dummy foo is created.
Split how we handle these cases. The first one is something MC should take care
of. The second one has to be handled by the caller.
llvm-svn: 120889
doing that if the target is darwin10 or newer.
This fixes
*) Direct object emission was producing objects without the workaround on
darwin9.
*) Assembly printing was producing objects with the workaround on linux.
llvm-svn: 120866
Eli Bendersky