SHF_ARM_PURECODE flag when being built with the -mexecute-only flag.
All code sections of an ELF must have the flag set for the final .text
section to be execute-only, otherwise the flag gets removed.
A HasData flag is added to MCSection to aid in the determination that
the section is empty. A virtual setTargetSectionFlags is added to
MCELFObjectTargetWriter to allow subclasses to set target specific
section flags to be added to sections which we then use in the ARM
backend to set SHF_ARM_PURECODE.
Patch by Ivan Lozano!
Reviewed By: echristo
Differential Revision: https://reviews.llvm.org/D48792
llvm-svn: 341593
Now that we create the label at the point of the directive, we don't
need to set the "current CV location", and then later when we emit the
next instruction, create a label for it and emit it.
DWARF still defers the labels used in .debug_loc until the next
instruction or value, for reasons unknown.
llvm-svn: 340883
Previously we followed the DWARF implementation, which waits until the
next instruction or data to emit the label to use in the .debug_loc
section. We might want to consider re-evaluating that design choice as
well, since it means the .loc skips alignment padding, for better or
worse.
This was the most minimal fix I could come up with, but we should be
able to do a lot of cleanups now that we don't need to save a pending CV
location on the CodeViewContext. I plan to do those next, but this
immediately fixes an assertion for some of our users.
llvm-svn: 340878
When emitting the difference between two symbols, the standard behavior is
that the difference will be resolved to an absolute value if both of the
symbols are offsets from the same data fragment. This is undesirable on
architectures such as RISC-V where relaxation in the linker may cause the
computed difference to become invalid. This caused an issue when compiling to
object code, where the size of a function in the debug information was already
calculated even though it could change as a consequence of relaxation in the
subsequent linking stage.
This patch inhibits the resolution of symbol differences to absolute values
where the target's AsmBackend has declared that it does not want these to be
folded.
Differential Revision: https://reviews.llvm.org/D45773
Patch by Edward Jones.
llvm-svn: 339864
AT_NAME was being emitted before the directory paths were remapped. This
ensures that all paths are remapped before anything is emitted.
An additional test case has been added.
Note that this only works if the replacement string is an absolute path.
If not, then AT_decl_file believes the new path is a relative path, and
joins that path with the compilation directory. I do not know of a good
way to resolve this.
Patch by: Siddhartha Bagaria (starsid)
Differential revision: https://reviews.llvm.org/D49169
llvm-svn: 336793
When manually finishing the object writer in dsymutil, it's possible
that there are pending labels that haven't been resolved. This results
in an assertion when the assembler tries to fixup a label that doesn't
have an address yet.
Differential revision: https://reviews.llvm.org/D49131
llvm-svn: 336688
debug compilation dir when compiling assembly files with -g.
Part of PR38050.
Patch by Siddhartha Bagaria!
Differential Revision: https://reviews.llvm.org/D48988
llvm-svn: 336680
This reverts rL331412. We didn't up using fragment atoms
in the wasm object writer after all.
Differential Revision: https://reviews.llvm.org/D48173
llvm-svn: 334734
On targets like Arm some relaxations may only be performed when certain
architectural features are available. As functions can be compiled with
differing levels of architectural support we must make a judgement on
whether we can relax based on the MCSubtargetInfo for the function. This
change passes through the MCSubtargetInfo for the function to
fixupNeedsRelaxation so that the decision on whether to relax can be made
per function. In this patch, only the ARM backend makes use of this
information. We must also pass the MCSubtargetInfo to applyFixup because
some fixups skip error checking on the assumption that relaxation has
occurred, to prevent code-generation errors applyFixup must see the same
MCSubtargetInfo as fixupNeedsRelaxation.
Differential Revision: https://reviews.llvm.org/D44928
llvm-svn: 334078
The idea is that a client that wants split dwarf would create a
specific kind of object writer that creates two files, and use it to
create the streamer.
Part of PR37466.
Differential Revision: https://reviews.llvm.org/D47050
llvm-svn: 332749
Avoid requirement that number of values must be known at assembler
time.
Fixes PR33586.
Reviewers: rnk, peter.smith, echristo, jyknight
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D46703
llvm-svn: 332741
This code previously existed only in MCMachOStreamer but is
useful for WebAssembly too. See: D46335
Differential Revision: https://reviews.llvm.org/D46297
llvm-svn: 331412
Teach AsmParser to check with Assembler for when evaluating constant
expressions. This improves the handing of preprocessor expressions
that must be resolved at parse time. This idiom can be found as
assembling-time assertion checks in source-level assemblers. Note that
this relies on the MCStreamer to keep sufficient tabs on Section /
Fragment information which the MCAsmStreamer does not. As a result the
textual output may fail where the equivalent object generation would
pass. This can most easily be resolved by folding the MCAsmStreamer
and MCObjectStreamer together which is planned for in a separate
patch.
Currently, this feature is only enabled for assembly input, keeping IR
compilation consistent between assembly and object generation.
Reviewers: echristo, rnk, probinson, espindola, peter.smith
Reviewed By: peter.smith
Subscribers: eraman, peter.smith, arichardson, jyknight, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D45164
llvm-svn: 331218
If no data or instructions are emitted after a location directive, we
should clear the cv_loc when we change sections, or it will be emitted
at the beginning of the next section. This violates our invariant that
all .cv_loc directives belong to the same section. Add clearer
assertions for this.
llvm-svn: 330884
Rely on the assembler to finalize the layout of the DWARF/Itanium
exception-handling LSDA. Rather than calculate the exact size of each
thing in the LSDA, use assembler directives:
To emit the offset to the TTBase label:
.uleb128 .Lttbase0-.Lttbaseref0
.Lttbaseref0:
To emit the size of the call site table:
.uleb128 .Lcst_end0-.Lcst_begin0
.Lcst_begin0:
... call site table entries ...
.Lcst_end0:
To align the type info table:
... action table ...
.balign 4
.long _ZTIi
.long _ZTIl
.Lttbase0:
Using assembler directives simplifies the compiler and allows switching
the encoding of offsets in the call site table from udata4 to uleb128 for
a large code size savings. (This commit does not change the encoding.)
The combination of the uleb128 followed by a balign creates an unfortunate
dependency cycle that the assembler must sometimes resolve either by
padding an LEB or by inserting zero padding before the type table. See
PR35809 or GNU as bug 4029.
Patch by Ryan Prichard!
llvm-svn: 324749
Infrastructure designed for padding code with nop instructions in key places such that preformance improvement will be achieved.
The infrastructure is implemented such that the padding is done in the Assembler after the layout is done and all IPs and alignments are known.
This patch by itself in a NFC. Future patches will make use of this infrastructure to implement required policies for code padding.
Reviewers:
aaboud
zvi
craig.topper
gadi.haber
Differential revision: https://reviews.llvm.org/D34393
Change-Id: I92110d0c0a757080a8405636914a93ef6f8ad00e
llvm-svn: 316413
MCObjectStreamer owns its MCCodeEmitter -- this fixes the types to reflect that,
and allows us to remove the last instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315531
MCObjectStreamer owns its MCAsmBackend -- this fixes the types to reflect that,
and allows us to remove another instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.
llvm-svn: 315410
functions.
This makes the ownership of the resulting MCObjectWriter clear, and allows us
to remove one instance of MCObjectStreamer's bizarre "holding ownership via
someone else's reference" trick.
llvm-svn: 315327
Summary:
This suppresses the generation of .Lcfi labels in our textual assembler.
It was annoying that this generated cascading .Lcfi labels:
llc foo.ll -o - | llvm-mc | llvm-mc
After three trips through MCAsmStreamer, we'd have three labels in the
output when none are necessary. We should only bother creating the
labels and frame data when making a real object file.
This supercedes D38605, which moved the entire .seh_ implementation into
MCObjectStreamer.
This has the advantage that we do more checking when emitting textual
assembly, as a minor efficiency cost. Outputting textual assembly is not
performance critical, so this shouldn't matter.
Reviewers: majnemer, MatzeB
Subscribers: qcolombet, nemanjai, javed.absar, eraman, hiraditya, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D38638
llvm-svn: 315259
This reverts commit 6389e7aa724ea7671d096f4770f016c3d86b0d54.
There is a bug in this implementation where the string value of the
checksum is outputted, instead of the actual hex bytes. Therefore the
checksum is incorrect, and this prevent pdbs from being loaded by visual
studio. Revert this until the checksum is emitted correctly.
llvm-svn: 313431
Summary:
The checksums had already been placed in the IR, this patch allows
MCCodeView to actually write it out to an MCStreamer.
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D37157
llvm-svn: 313374
We were previously silently emitting bogus data in release mode,
making it very hard to diagnose the error, or crashing with an
assert in debug mode. A proper diagnostic is now always emitted
when the value to be emitted is out of range.
llvm-svn: 303041
Dont emit Mapping symbols for sections that contain only data.
Summary:
Dont emit mapping symbols for sections that contain only data.
Reviewers: rengolin, weimingz, kparzysz, t.p.northover, peter.smith
Reviewed By: t.p.northover
Patched by Shankar Easwaran <shankare@codeaurora.org>
Subscribers: alekseyshl, t.p.northover, llvm-commits
Differential Revision: https://reviews.llvm.org/D30724
llvm-svn: 299392
This makes sure we get the same redefinition rules regardless of who
is printing (asm parser, codegen) and to what (asm, obj).
This fixes an unintentional regression in r293936.
llvm-svn: 294752
Currently, the error messages we emit for the .org directive when the
expression is not absolute or is out of range do not include the line
number of the directive, so it can be hard to track down the problem if
a file contains many .org directives.
This patch stores the source location in the MCOrgFragment, so that it
can be used for diagnostics emitted during layout.
Since layout is an iterative process, and the errors are detected during
each iteration, it would have been possible for errors to be reported
multiple times. To prevent this, I've made the assembler bail out after
each iteration if any errors have been reported. This will still allow
multiple unrelated errors to be reported in the common case where they
are all detected in the first round of layout.
Differential Revision: https://reviews.llvm.org/D27411
llvm-svn: 289643
Summary:
Previously we were trying to represent this with the "contains" list of
the .cv_inline_linetable directive, which was not enough information.
Now we directly represent the chain of inlined call sites, so we know
what location to emit when we encounter a .cv_loc directive of an inner
inlined call site while emitting the line table of an outer function or
inlined call site. Fixes PR29146.
Also fixes PR29147, where we would crash when .cv_loc directives crossed
sections. Now we write down the section of the first .cv_loc directive,
and emit an error if any other .cv_loc directive for that function is in
a different section.
Also fixes issues with discontiguous inlined source locations, like in
this example:
volatile int unlikely_cond = 0;
extern void __declspec(noreturn) abort();
__forceinline void f() {
if (!unlikely_cond) abort();
}
int main() {
unlikely_cond = 0;
f();
unlikely_cond = 0;
}
Previously our tables gave bad location information for the 'abort'
call, and the debugger wouldn't snow the inlined stack frame for 'f'.
It is important to emit good line tables for this code pattern, because
it comes up whenever an asan bug occurs in an inlined function. The
__asan_report* stubs are generally placed after the normal function
epilogue, leading to discontiguous regions of inlined code.
Reviewers: majnemer, amccarth
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D24014
llvm-svn: 280822
MCContext already has many tasks, and separating CodeView out from it is
probably a good idea. The .cv_loc tracking was modelled on the DWARF
tracking which lived directly in MCContext.
Removes the inclusion of MCCodeView.h from MCContext.h, so now there are
only 10 build actions while I hack on CodeView support instead of 265.
llvm-svn: 279847
Assembler directives .dtprelword, .dtpreldword, .tprelword, and
.tpreldword generates relocations R_MIPS_TLS_DTPREL32, R_MIPS_TLS_DTPREL64,
R_MIPS_TLS_TPREL32, and R_MIPS_TLS_TPREL64 respectively.
The main motivation for this patch is to be able to write test cases
for checking correctness of the LLD linker's behaviour.
Differential Revision: https://reviews.llvm.org/D23669
llvm-svn: 279439
This matches the behavior of GNU assembler which supports symbolic
expressions in absolute expressions used in assembly directives.
Differential Revision: http://reviews.llvm.org/D20752
llvm-svn: 271102
