This reverts commit d054c7ee2e9f4f98af7f22a5b00a941eb919bd59.
There are discussions about the utility name, its functionality and user interface.
Revert before we reach consensus.
This patch adds support for the LOG2CEIL builtin function in linker scripts: https://sourceware.org/binutils/docs/ld/Builtin-Functions.html#index-LOG2CEIL_0028exp_0029
As documented for LD, and to keep compatibility, LOG2CEIL(0) returns 0 (not -inf).
The test vectors are somewhat arbitrary. We check minimum values (0-4); middle values (2^32, and 2^32+1); and the maximum value (2^64-1).
The checks for LOG2CEIL explicitly use full 64-bit values (16 hex digits). This is needed to properly verify that -inf and other interesting results aren't returned. (For some reason, all other tests in operators.test use only 14 digits.)
Differential revision: https://reviews.llvm.org/D84054
See https://lists.llvm.org/pipermail/llvm-dev/2020-July/143373.html
"[llvm-dev] Multiple documents in one test file" for some discussions.
`extract part filename` splits the input file into multiple parts separated by
regex `^(.|//)--- ` and extract the specified part to stdout or the
output file (if specified).
Use case A (organizing input of different formats (e.g. linker
script+assembly) in one file).
```
// RUN: extract lds %s -o %t.lds
// RUN: extract asm %s -o %t.s
// RUN: llvm-mc %t.s -o %t.o
// RUN: ld.lld -T %t.lds %t.o -o %t
This is sometimes better than the %S/Inputs/ approach because the user
can see the auxiliary files immediately and don't have to open another file.
```
Use case B (for utilities which don't have built-in input splitting
feature):
```
// RUN: extract case1 %s | llc | FileCheck %s --check-prefix=CASE1
// RUN: extract case2 %s | llc | FileCheck %s --check-prefix=CASE2
Combing tests prudently can improve readability.
This is sometimes better than having multiple test files.
```
Since this is a new utility, there is no git history concerns for
UpperCase variable names. I use lowerCase variable names like mlir/lld.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D83834
If neither AT(lma) nor AT>lma_region is specified,
D76995 keeps `lmaOffset` (LMA - VMA) if the previous section is in the
default LMA region.
This patch additionally checks that the two sections are in the same
memory region.
Add a test case derived from https://bugs.llvm.org/show_bug.cgi?id=45313
.mdata : AT(0xfb01000) { *(.data); } > TCM
// It is odd to make .bss inherit lmaOffset, because the two sections
// are in different memory regions.
.bss : { *(.bss) } > DDR
With this patch, section VMA/LMA match GNU ld. Note, GNU ld supports
out-of-order (w.r.t sh_offset) sections and places .text and .bss in the
same PT_LOAD. We don't have that behavior.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D81986
Summary:
Lld test ELF/linkerscript/thunk-gen-mips.s was accidentally disabled due
to the use of wrong FileCheck directives. As a result the test seems to
have bitrotted as it fails to pass if fixing the directive. To ease
updates to the test in case of change of the __start address the checks
have been changed to use numeric variables to express all the addresses
based on the __start address.
Reviewed By: atanasyan
Differential Revision: https://reviews.llvm.org/D79270
Lld test ELF/linkerscript/input-archive.s fails when path contain a @
because is not accepted in unquoted token in linker scripts which leads
to the path being broken in 2 around the @. This commit quotes the path
used in the linker script created by this and similar testcases allowing
the test to pass even in the presence of an @ sign in the path.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D79103
For a relative path in INPUT() or GROUP(), this patch changes the search order by adding the directory of the current linker script.
The new search order (consistent with GNU ld >= 2.35 regarding the new test `test/ELF/input-relative.s`):
1. the directory of the current linker script (GNU ld from Binutils 2.35 onwards; https://sourceware.org/bugzilla/show_bug.cgi?id=25806)
2. the current working directory
3. library paths (-L)
This behavior makes it convenient to replace a .so or .a with a linker script with additional input. For example, glibc
```
% cat /usr/lib/x86_64-linux-gnu/libm.a
/* GNU ld script
*/
OUTPUT_FORMAT(elf64-x86-64)
GROUP ( /usr/lib/x86_64-linux-gnu/libm-2.29.a /usr/lib/x86_64-linux-gnu/libmvec.a )
```
could be simplified as `GROUP(libm-2.29.a libmvec.a)`.
Another example is to make libc++.a a linker script:
```
INPUT(libc++.a.1 libc++abi.a)
```
Note, -l is not affected.
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D77779
Currently, `error: incompatible section flags for .rodata` is reported
when we mix SHF_LINK_ORDER and non-SHF_LINK_ORDER sections in an output section.
This is overconstrained. This patch allows mixed flags with the
requirement that SHF_LINK_ORDER sections must be contiguous. Mixing
flags is used by Linux aarch64 (https://github.com/ClangBuiltLinux/linux/issues/953)
.init.data : { ... KEEP(*(__patchable_function_entries)) ... }
When the integrated assembler is enabled, clang's -fpatchable-function-entry=N[,M]
implementation sets the SHF_LINK_ORDER flag (D72215) to fix a number of
garbage collection issues.
Strictly speaking, the ELF specification does not require contiguous
SHF_LINK_ORDER sections but for many current uses of SHF_LINK_ORDER like
.ARM.exidx/__patchable_function_entries there has been a requirement for
the sections to be contiguous on top of the requirements of the ELF
specification.
This patch also imposes one restriction: SHF_LINK_ORDER sections cannot
be separated by a symbol assignment or a BYTE command. Not allowing BYTE
is a natural extension that a non-SHF_LINK_ORDER cannot be a separator.
Symbol assignments can delimiter the contents of SHF_LINK_ORDER
sections. Allowing SHF_LINK_ORDER sections across symbol assignments
(especially __start_/__stop_) can make things hard to explain. The
restriction should not be a problem for practical use cases.
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D77007
This fixes PR# 45336.
Output sections described in a linker script as NOLOAD with no input sections would be marked as SHT_PROGBITS.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D76981
The error previously talked about a "section header" but was actually
referring to a program header.
Reviewed by: grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D76846
This behavior matches GNU ld and seems reasonable.
```
// If a SECTIONS command is not specified
.text.* -> .text
.rodata.* -> .rodata
.init_array.* -> .init_array
```
A proposed Linux feature CONFIG_FG_KASLR may depend on the GNU ld behavior.
Reword a comment about -z keep-text-section-prefix and a comment about
CommonSection (deleted by rL286234).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75225
This essentially drops the change by r288021 (discussed with Georgii Rymar
and Peter Smith and noted down in the release note of lld 10).
GNU ld>=2.31 enables -z separate-code by default for Linux x86. By
default (in the absence of a PHDRS command) a readonly PT_LOAD is
created, which is different from its traditional behavior.
Not emulating GNU ld's traditional behavior is good for us because it
improves code consistency (we create a readonly PT_LOAD in the absence
of a SECTIONS command).
Users can add --no-rosegment to restore the previous behavior (combined
readonly and read-executable sections in a single RX PT_LOAD).
Fixes https://bugs.llvm.org/show_bug.cgi?id=44903
It is about the following case:
```
SECTIONS {
.foo : { *(.foo) } =0x90909090
/DISCARD/ : { *(.bar) }
}
```
Here while parsing the fill expression we treated the
"/" of "/DISCARD/" as operator.
With this change, suggested by Fangrui Song, we do
not allow expressions with operators (e.g. "0x1100 + 0x22")
that are not wrapped into round brackets. It should not
be an issue for users, but helps to resolve parsing ambiguity.
Differential revision: https://reviews.llvm.org/D74687
Follow-up for D74433
What the function returns are almost standard BFD names, except that "ELF" is
in uppercase instead of lowercase.
This patch changes "ELF" to "elf" and changes ARM/AArch64 to use their BFD names.
MIPS and PPC64 have endianness differences as well, but this patch does not intend to address them.
Advantages:
* llvm-objdump: the "file format " line matches GNU objdump on ARM/AArch64 objects
* "file format " line can be extracted and fed into llvm-objcopy -O literally.
(https://github.com/ClangBuiltLinux/linux/issues/779 has such a use case)
Affected tools: llvm-readobj, llvm-objdump, llvm-dwarfdump, MCJIT (internal implementation detail, not exposed)
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D76046
-M output can be useful when diagnosing an "error: output file too large" problem (emitted in openFile()).
I just ran into such a situation where I had to debug an erronerous
Linux kernel linker script. It tried to create a file larger than
INT64_MAX bytes.
This patch could have helped https://bugs.llvm.org/show_bug.cgi?id=44715 as well.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75966
See `docs/ELF/linker_script.rst` for the new computation for sh_addr and sh_addralign.
`ALIGN(section_align)` now means: "increase alignment to section_align"
(like yet another input section requirement).
The "start of section .foo changes from 0x11 to 0x20" warning no longer
makes sense. Change it to warn if sh_addr%sh_addralign!=0.
To decrease the alignment from the default max_input_align,
use `.output ALIGN(8) : {}` instead of `.output : ALIGN(8) {}`
See linkerscript/section-address-align.test as an example.
When both an output section address and ALIGN are set (can be seen as an
"undefined behavior" https://sourceware.org/ml/binutils/2020-03/msg00115.html),
lld may align more than GNU ld, but it makes a linker script working
with GNU ld hard to break with lld.
This patch can be considered as restoring part of the behavior before D74736.
Differential Revision: https://reviews.llvm.org/D75724
```
createFiles(args)
readDefsym
readerLinkerScript(*mb)
...
readMemory
readMemoryAssignment("ORIGIN", "org", "o") // eagerly evaluated
target = getTarget();
link(args)
writeResult<ELFT>()
...
finalizeSections()
script->processSymbolAssignments()
addSymbol(cmd) // with this patch, evaluated here
```
readMemoryAssignment eagerly evaluates ORIGIN/LENGTH and returns an uint64_t.
This patch postpones the evaluation to make
* --defsym and symbol assignments
* `CONSTANT(COMMONPAGESIZE)` (requires a non-null `lld:🧝:target`)
work. If the expression somehow requires interaction with memory
regions, the circular dependency may cause the expression to evaluate to
a strange value. See the new test added to memory-err.s
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75763
The new behavior matches GNU objdump. A pair of angle brackets makes tests slightly easier.
`.foo:` is not unique and thus cannot be used in a `CHECK-LABEL:` directive.
Without `-LABEL`, the CHECK line can match the `Disassembly of section`
line and causes the next `CHECK-NEXT:` to fail.
```
Disassembly of section .foo:
0000000000001634 .foo:
```
Bdragon: <> has metalinguistic connotation. it just "feels right"
Reviewed By: rupprecht
Differential Revision: https://reviews.llvm.org/D75713
This fixes several issues. The behavior changes are:
A SHN_COMMON symbol does not have the 'g' flag.
An undefined symbol does not have 'g' or 'l' flag.
A STB_GLOBAL SymbolRef::ST_Unknown symbol has the 'g' flag.
A STB_LOCAL SymbolRef::ST_Unknown symbol has the 'l' flag.
Reviewed By: rupprecht
Differential Revision: https://reviews.llvm.org/D75659
They are purposefully skipped by input section descriptions (rL295324).
Similarly, --orphan-handling= should not warn/error for them.
This behavior matches GNU ld.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75151
This makes --orphan-handling= less noisy.
This change also improves our compatibility with GNU ld.
GNU ld special cases .symtab, .strtab and .shstrtab . We need output section
descriptions for .symtab, .strtab and .shstrtab to suppress:
<internal>:(.symtab) is being placed in '.symtab'
<internal>:(.shstrtab) is being placed in '.shstrtab'
<internal>:(.strtab) is being placed in '.strtab'
With --strip-all, .symtab and .strtab can be omitted (note, --strip-all is not compatible with --emit-relocs).
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D75149
When the output section address (addrExpr) is specified, GNU ld warns if
sh_addr is different. This patch implements the warning.
Note, LinkerScript::assignAddresses can be called more than once. We
need to record the changed section addresses, and only report the
warnings after the addresses are finalized.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D74741
Follow-up for D74286.
Notations:
* alignExpr: the computed ALIGN value
* max_input_align: the maximum of input section alignments
This patch changes the following two cases to match GNU ld:
* When ALIGN is present, GNU ld sets output sh_addr to alignExpr, while lld use max(alignExpr, max_input_align)
* When addrExpr is specified but alignExpr is not, GNU ld sets output sh_addr to addrExpr, while lld uses `advance(0, max_input_align)`
Note, sh_addralign is still set to max(alignExpr, max_input_align).
lma-align.test is enhanced a bit to check we don't overalign sh_addr.
fixSectionAlignments() sets addrExpr but not alignExpr for the `!hasSectionsCommand` case.
This patch sets alignExpr as well so that max_input_align will be respected.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D74736
Summary:
Even though this test is a check for failure, lld still attempts
to open the final output file, which fails when the default "a.out"
file is used and the current directory is read-only. Specifying an
output file works around this problem.
Reviewers: espindola
Subscribers: emaste, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74523
D43468+D44380 added INSERT [AFTER|BEFORE] for non-orphan sections. This patch
makes INSERT work for orphan sections as well.
`SECTIONS {...} INSERT [AFTER|BEFORE] .foo` does not set `hasSectionCommands`, so the result
will be similar to a regular link without a linker script. The differences when `hasSectionCommands` is set include:
* image base is different
* -z noseparate-code/-z noseparate-loadable-segments are unavailable
* some special symbols such as `_end _etext _edata` are not defined
The behavior is similar to GNU ld:
INSERT is not considered an external linker script.
This feature makes the section layout more flexible. It can be used to:
* Place .nv_fatbin before other readonly SHT_PROGBITS sections to mitigate relocation overflows.
* Disturb the layout to expose address sensitive application bugs.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D74375
GNU ld has a counterintuitive lang_propagate_lma_regions rule.
```
// .foo's LMA region is propagated to .bar because their VMA region is the same,
// and .bar does not have an explicit output section address (addr_tree).
.foo : { *(.foo) } >RAM AT> FLASH
.bar : { *(.bar) } >RAM
// An explicit output section address disables propagation.
.foo : { *(.foo) } >RAM AT> FLASH
.bar . : { *(.bar) } >RAM
```
In both cases, lld thinks .foo's LMA region is propagated and
places .bar in the same PT_LOAD, so lld diverges from GNU ld w.r.t. the
second case (lma-align.test).
This patch changes Writer<ELFT>::createPhdrs to disable propagation
(start a new PT_LOAD). A user of the first case can make linker scripts
portable by explicitly specifying `AT>`. By contrast, there was no
workaround for the old behavior.
This change uncovers another LMA related bug in assignOffsets() where
`ctx->lmaOffset = 0;` was omitted. It caused a spurious "load address
range overlaps" error for at2.test
The new PT_LOAD rule is complex. For convenience, I listed the origins of some subexpressions:
* rL323449: `sec->memRegion == load->firstSec->memRegion`; linkerscript/at3.test
* D43284: `load->lastSec == Out::programHeaders` (don't start a new PT_LOAD after program headers); linkerscript/at4.test
* D58892: `sec != relroEnd` (start a new PT_LOAD after PT_GNU_RELRO)
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D74297
When lmaRegion is non-null, respect `sec->alignment`
This rule is analogous to `switchTo(sec)` which advances sh_addr (VMA).
This fixes the p_paddr misalignment issue as reported by
https://android-review.googlesource.com/c/trusty/external/trusted-firmware-a/+/1230058
Note, `sec->alignment` is the maximum of ALIGN and input section alignments. We may overalign LMA than GNU ld.
linkerscript/align-lma.s has a FIXME that demonstrates another bug:
`.bss ... >RAM` should be placed in a different PT_LOAD (GNU ld
behavior) because its lmaRegion (nullptr) is different from the previous
section's lmaRegion (ROM).
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D74286
Summary:
Linker scripts allow filenames to be put in double quotes to prevent
characters in filenames that are part of the linker script syntax from
having their special meaning. Case in point the * wildcard character.
Availability of double quoting filenames also allows to fix a failure in
ELF/linkerscript/filename-spec.s when the path contain a @ which the
lexer consider as a special characters and thus break up a filename
containing it. This may happens under Jenkins which createspath such as
pipeline@2.
To avoid the need for escaping GlobPattern metacharacters in filename
in double quotes, GlobPattern::create is augmented with a new parameter
to request literal matching instead of relying on the presence of a
wildcard character in the pattern.
Reviewers: jhenderson, MaskRay, evgeny777, espindola, alexshap
Reviewed By: MaskRay
Subscribers: peter.smith, grimar, ruiu, emaste, arichardson, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72517
Linux powerpc discards `*(.gnu.version*)` (arch/powerpc/kernel/vmlinux.lds.S)
to suppress --orphan-handling=warn warnings in the -pie output `.tmp_vmlinux1`
The support is simple. Just add isLive() to:
1) Fix an assertion in SectionBase::getPartition() called by VersionTableSection::isNeeded().
2) Suppress DT_VERSYM, DT_VERDEF, DT_VERNEED and DT_VERNEEDNUM, if the relevant section is discarded.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D71819
