`BlockAddress`es are interesting in that they can reference basic blocks
from *outside* the block's function. Since basic blocks are not global
values, this presents particular challenges for lazy parsing.
One corner case was found in PR11677 and fixed in r147425. In that
case, a global variable references a block address. It's necessary to
load the relevant function to resolve the forward reference before doing
anything with the module.
By inspection, I found (and have fixed here) two other cases:
- An instruction from one function references a block address from
another function, and only the first function is lazily loaded.
I fixed this the same way as PR11677: by eagerly loading the
referenced function.
- A function whose block address is taken is dematerialized, leaving
invalid references to it.
I fixed this by refusing to dematerialize functions whose block
addresses are taken (if you have to load it, you can't unload it).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214559 91177308-0d34-0410-b5e6-96231b3b80d8
This is more convenient for callers. No functionality change, this will
be used in a next patch to the gold plugin.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214218 91177308-0d34-0410-b5e6-96231b3b80d8
This will let users in other libraries know which error occurred. In particular,
it will be possible to check if the parsing failed or if the file is not
bitcode.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214209 91177308-0d34-0410-b5e6-96231b3b80d8
Predict and serialize use-list order in bitcode. This makes the option
`-preserve-bc-use-list-order` work *most* of the time, but this is still
experimental.
- Builds a full value-table up front in the writer, sets up a list of
use-list orders to write out, and discards the table. This is a
simpler first step than determining the order from the various
overlapping IDs of values on-the-fly.
- The shuffles stored in the use-list order list have an unnecessarily
large memory footprint.
- `blockaddress` expressions cause functions to be materialized
out-of-order. For now I've ignored this problem, so use-list orders
will be wrong for constants used by functions that have block
addresses taken. There are a couple of ways to fix this, but I
don't have a concrete plan yet.
- When materializing functions lazily, the use-lists for constants
will not be correct. This use case is out of scope: what should the
use-list order be, if it's incomplete?
This is part of PR5680.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214125 91177308-0d34-0410-b5e6-96231b3b80d8
This attribute indicates that the parameter or return pointer is
dereferenceable. Practically speaking, loads from such a pointer within the
associated byte range are safe to speculatively execute. Such pointer
parameters are common in source languages (C++ references, for example).
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This was an oversight in the original support. As it is, I stuffed this
bit into the alignment. The alignment is stored in log2 form, so it
doesn't need more than 5 bits, given that Value::MaximumAlignment is 1
<< 29.
Reviewers: nicholas
Differential Revision: http://reviews.llvm.org/D3943
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This reverts commit r212342.
We can get a StringRef into the current Record, but not one in the bitcode
itself since the string is compressed in it.
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This new IR facility allows us to represent the object-file semantic of
a COMDAT group.
COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.
This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.
Differential Revision: http://reviews.llvm.org/D4178
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This allows us to just use a std::unique_ptr to store the pointer to the buffer.
The flip side is that they have to support releasing the buffer back to the
caller.
Overall this looks like a more efficient and less brittle api.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211542 91177308-0d34-0410-b5e6-96231b3b80d8
We do have use cases for the bitcode reader owning the buffer or not, but we
always know which one we have when we construct it.
It might be possible to simplify this further, but this is a step in the
right direction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211205 91177308-0d34-0410-b5e6-96231b3b80d8
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.
This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.
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This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203083 91177308-0d34-0410-b5e6-96231b3b80d8
This moves the old pass creation functionality to its own header and
updates the callers of that routine. Then it adds a new PM supporting
bitcode writer to the header file, and wires that up in the opt tool.
A test is added that round-trips code into bitcode and back out using
the new pass manager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199078 91177308-0d34-0410-b5e6-96231b3b80d8
The inalloca attribute is designed to support passing C++ objects by
value in the Microsoft C++ ABI. It behaves the same as byval, except
that it always implies that the argument is in memory and that the bytes
are never copied. This attribute allows the caller to take the address
of an outgoing argument's memory and execute arbitrary code to store
into it.
This patch adds basic IR support, docs, and verification. It does not
attempt to implement any lowering or fix any possibly broken transforms.
When this patch lands, a complete description of this feature should
appear at http://llvm.org/docs/InAlloca.html .
Differential Revision: http://llvm-reviews.chandlerc.com/D2173
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This function attribute indicates that the function is not optimized
by any optimization or code generator passes with the
exception of interprocedural optimization passes.
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The bitcode representation attribute kinds are encoded into / decoded from
should be independent of the current set of LLVM attributes and their position
in the AttrKind enum. This patch explicitly encodes attributes to fixed bitcode
values.
With this patch applied, LLVM does not silently misread attributes written by
LLVM 3.3. We also enhance the decoding slightly such that an error message is
printed if an unknown AttrKind encoding was dected.
Bonus: Dropping bitcode attributes from AttrKind is now easy, as old AttrKinds
do not need to be kept to support the Bitcode reader.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187186 91177308-0d34-0410-b5e6-96231b3b80d8
llvm-ar is the only tool that needs to write archive files. Every other tool
should be able to use the lib/Object interface.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184083 91177308-0d34-0410-b5e6-96231b3b80d8
Archive files (.a) can have a symbol table indicating which object
files in them define which symbols. The purpose of this symbol table
is to speed up linking by allowing the linker the read only the .o
files it is actually going to use instead of having to parse every
object's symbol table.
LLVM's archive library currently supports a LLVM specific format for
such table. It is hard to see any value in that now that llvm-ld is
gone:
* System linkers don't use it: GNU ar uses the same plugin as the
linker to create archive files with a regular index. The OS X ar
creates no symbol table for IL files, I assume the linker just parses
all IL files.
* It doesn't interact well with archives having both IL and native objects.
* We probably don't want to be responsible for yet another archive
format variant.
This patch then:
* Removes support for creating and reading such index from lib/Archive.
* Remove llvm-ranlib, since there is nothing left for it to do.
We should in the future add support for regular indexes to llvm-ar for
both native and IL objects. When we do that, llvm-ranlib should be
reimplemented as a symlink to llvm-ar, as it is equivalent to "ar s".
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There was exactly one caller using this API right, the others were relying on
specific behavior of the default implementation. Since it's too hard to use it
right just remove it and standardize on the default behavior.
Defines away PR16132.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182636 91177308-0d34-0410-b5e6-96231b3b80d8
BitstreamWriter asserts that when blob data is written from the record
element vector, each element fits in a byte. However, if the record
elements are specified as a SmallVector of 'char', this causes a warning
from -Wtautological-constant-out-of-range-compare. Fix this by using
llvm::isUInt<8> instead of a plain comparison against 256.
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This is some initial code for emitting the attribute groups into the bitcode.
NOTE: This format *may* change! Do not rely upon the attribute groups' bitcode
not changing.
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bitcode writer would generate abbrev records saying that the abbrev should be
filled with fixed zero-bit bitfields (this happens in the .bc writer when
the number of types used in a module is exactly one, since log2(1) == 0).
In this case, just handle it as a literal zero. We can't "just fix" the writer
without breaking compatibility with existing bc files, so have the abbrev reader
do the substitution.
Strengthen the assert in read to reject reads of zero bits so we catch such
crimes in the future, and remove the special case designed to handle this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174801 91177308-0d34-0410-b5e6-96231b3b80d8
instead of always 32-bits at a time) with two changes:
1. Make Read(0) always return zero without affecting the state of our cursor.
2. Hack word_t to always be 32 bits, as staging.
These two caveats will change shortly.
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Rename the PARAMATTR_CODE_ENTRY to PARAMATTR_CODE_ENTRY_OLD. It will be replaced
by another encoding. Keep around the current LLVM attribute encoder/decoder
code, but move it to the bitcode directories so that no one's tempted to use
them.
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This cuts in half the number of virtual methods called to refill that word when compiling on a 64-bit
host, and will make 64-bit read operations faster.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173072 91177308-0d34-0410-b5e6-96231b3b80d8
BLOB (i.e., large, performance intensive data) in a bitcode file was switched to
invoking one virtual method call per byte read. Now we do one virtual call per
BLOB.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173065 91177308-0d34-0410-b5e6-96231b3b80d8
