This patch makes the final major change of the RemoveDIs project, changing the
default IR output from debug intrinsics to debug records. This is expected to
break a large number of tests: every single one that tests for uses or
declarations of debug intrinsics and does not explicitly disable writing
records.
If this patch has broken your downstream tests (or upstream tests on a
configuration I wasn't able to run):
1. If you need to immediately unblock a build, pass
`--write-experimental-debuginfo=false` to LLVM's option processing for all
failing tests (remember to use `-mllvm` for clang/flang to forward arguments to
LLVM).
2. For most test failures, the changes are trivial and mechanical, enough that
they can be done by script; see the migration guide for a guide on how to do
this: https://llvm.org/docs/RemoveDIsDebugInfo.html#test-updates
3. If any tests fail for reasons other than FileCheck check lines that need
updating, such as assertion failures, that is most likely a real bug with this
patch and should be reported as such.
For more information, see the recent PSA:
https://discourse.llvm.org/t/psa-ir-output-changing-from-debug-intrinsics-to-debug-records/79578
This reverts commit a4d5fd4d2ee9470e55345a9540f6b6fb6faf66e1.
The above commit breaks greendragon lldb bots:
Link to failing builds:
https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/63300/https://green.lab.llvm.org/green/view/LLDB/job/as-lldb-cmake/10345/
I found this PR to be the offending one after using git bisect with the
cmake invocation:
cmake -G Ninja ../llvm -DCMAKE_BUILD_TYPE=Release
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON
'-DLLVM_TARGETS_TO_BUILD=X86;ARM;AArch64'
-DLLVM_ENABLE_ASSERTIONS:BOOL=TRUE
-DLLVM_ENABLE_MODULES=On
-DLLVM_ENABLE_PROJECTS='clang;lld;lldb;cross-project-tests'
-DLLVM_VERSION_PATCH=99
'-DLLVM_ENABLE_RUNTIMES=libcxx;libcxxabi;compiler-rt'
and running
ninja lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/CodeGenPassBuilder.cpp.o
Just copy the `runOnFunction` method from `SafeStackLegacyPass` and
remove the workaround for computing analysis lazily, the analysis result
in new pass manager is computed lazily by default.
This patch re-implements a variety of debug-info maintenence functions
to use DPValues instead of DbgValueInst's: supporting the "new"
non-intrinsic representation of debug-info. As per [0], we need to have
parallel implementations of various utilities for a time, and these are
the most fundamental utilities used throughout the compiler.
I've added --try-experimental-debuginfo-iterators to a variety of RUN
lines: this is a flag that turns on "new debug-info" if it's built into
LLVM, and not otherwise. This should ensure that we have the same
behaviour for the same IR inputs, but using a different internal
representation. For the most part these changes affect SROA/Mem2Reg
promotion of dbg.declares into dbg.value intrinsics (now DPValues),
we're leaving dbg.declares as instructions until later in the day.
There's also some salvaging changes made.
I believe the tests that I've added cover almost all the code being
updated here. The only thing I'm not confident about is SimplifyCFG,
which calls rewriteDebugUsers down a variety of code paths. Those
changes can't immediately get full coverage as an additional patch is
needed that updates handling of Unreachable instructions, will upload
that shortly.
[0]
https://discourse.llvm.org/t/rfc-instruction-api-changes-needed-to-eliminate-debug-intrinsics-from-ir/68939/9
There are many tests that specify a target triple/CPU flags but no
DataLayout which can lead to IR being generated that has unusual
behaviour. This commit attempts to use the default DataLayout based
on the relevant flags if there is no explicit override on the command
line or in the IR file.
One thing that is not currently possible to differentiate from a missing
datalayout `target datalayout = ""` in the IR file since the current
APIs don't allow detecting this case. If it is considered useful to
support this case (instead of passing "-data-layout=" on the command
line), I can change IR parsers to track whether they have seen such a
directive and change the callback type.
Differential Revision: https://reviews.llvm.org/D141060
This is a follow-up to b71edfaa4ec3c998aadb35255ce2f60bba2940b0
since I forgot the lit.local.cfg files in that one.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: barannikov88, kwk
Differential Revision: https://reviews.llvm.org/D150762
Current stack size diagnostics ignore the size of the unsafe stack.
This patch attaches the size of the static portion of the unsafe stack
to the function as metadata, which can be used by the backend to emit
diagnostics regarding stack usage.
Reviewed By: phosek, mcgrathr
Differential Revision: https://reviews.llvm.org/D119996
Rather than rewriting the alloca pointer to zero, use
removePointerBase() to drop the base pointer. This will simply bail
if the base pointer is not the alloca. We could try doing something
more fancy here (like dropping the sources not based on the alloca
on the premise that they aren't SafeStack-relevant), but I don't
think that's worthwhile.
Fixes https://github.com/llvm/llvm-project/issues/54784.
Differential Revision: https://reviews.llvm.org/D123309
This was disabled in 2acea2786b9fd40e1aba018b165834168535e164 as a
work-around for Issue #31491. I've reduced the test case from that bug
and confirmed that it is now fixed.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D120866
Using the proper API automatically sets `__stack_chk_guard` to `dso_local` if
`Reloc::Static`. This wasn't strictly necessary until recently when dso_local was
no longer implied by `TargetMachine::shouldAssumeDSOLocal` for
`__stack_chk_guard`. By using the proper API, we can avoid generating unnecessary
GOT relocations.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D102646
Since d6de1e1a71406c75a4ea4d5a2fe84289f07ea3a1, no attributes is quivalent to
setting attribute to false.
This is a preliminary commit for https://reviews.llvm.org/D99080
SafeStack instrumentation should not insert anything inbetween musttail call and return instruction.
For every ReturnInst that needs to be instrumented, we adjust the insertion point to the musttail call if exists.
Differential Revision: https://reviews.llvm.org/D90702
If we can't identify alloca used in lifetime marker we
need to assume to worst case scenario.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D84630
Summary:
Replace any extant metadata uses of a dying instruction with undef to
preserve debug info accuracy. Some alternatives include:
- Treat Instruction like any other Value, and point its extant metadata
uses to an empty ValueAsMetadata node. This makes extant dbg.value uses
trivially dead (i.e. fair game for deletion in many passes), leading to
stale dbg.values being in effect for too long.
- Call salvageDebugInfoOrMarkUndef. Not needed to make instruction removal
correct. OTOH results in wasted work in some common cases (e.g. when all
instructions in a BasicBlock are deleted).
This came up while discussing some basic cases in
https://reviews.llvm.org/D80052.
Reviewers: jmorse, TWeaver, aprantl, dexonsmith, jdoerfert
Subscribers: jholewinski, qcolombet, hiraditya, jfb, sstefan1, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80264
This will allow us to use the datalayout to disambiguate other
constructs in IR, like load alignment. Split off from D78403.
Differential Revision: https://reviews.llvm.org/D78413
This is a follow up to D64971. While we need to insert the deref after
the offset, it needs to come before the remaining elements in the
original expression since the deref needs to happen before the LLVM
fragment if present.
Differential Revision: https://reviews.llvm.org/D65172
llvm-svn: 366865
While debugging code that uses SafeStack, we've noticed that LLVM
produces an invalid DWARF. Concretely, in the following example:
int main(int argc, char* argv[]) {
std::string value = "";
printf("%s\n", value.c_str());
return 0;
}
DWARF would describe the value variable as being located at:
DW_OP_breg14 R14+0, DW_OP_deref, DW_OP_constu 0x20, DW_OP_minus
The assembly to get this variable is:
leaq -32(%r14), %rbx
The order of operations in the DWARF symbols is incorrect in this case.
Specifically, the deref is incorrect; this appears to be incorrectly
re-inserted in repalceOneDbgValueForAlloca.
With this change which inserts the deref after the offset instead of
before it, LLVM produces correct DWARF:
DW_OP_breg14 R14-32
Differential Revision: https://reviews.llvm.org/D64971
llvm-svn: 366726
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
Summary:
Currently, the SafeStack analysis disallows out-of-bounds writes but not
out-of-bounds reads for mem intrinsics like llvm.memcpy. This could
cause leaks of pointers to the safe stack by leaking spilled registers/
frame pointers. Check for allocas used as source or destination pointers
to mem intrinsics.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: pcc, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D51334
llvm-svn: 341116
Otherwise, the debug info is incorrect. On its own, this is mostly
harmless, but the safe-stack also later inlines the call to
__safestack_pointer_address, which leads to debug info with the wrong
scope, which eventually causes an assertion failure (and incorrect debug
info in release mode).
Differential Revision: https://reviews.llvm.org/D51075
llvm-svn: 340651
Instead of asserting that the function doesn't have any unreachable
code, just ignore it for the purpose of computing liveness.
Differential Revision: https://reviews.llvm.org/D51070
llvm-svn: 340456
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
Summary:
This change is part of step five in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. In particular, this changes the
creation of memcpys in the SafeStack pass to set the alignment of the destination object to
its stack alignment while separately setting the source byval arguments alignment to its
alignment.
Steps:
Step 1) Remove alignment parameter and create alignment parameter attributes for
memcpy/memmove/memset. ( rL322965, rC322964, rL322963 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
source and dest alignments. ( rL323597 )
Step 3) Update Clang to use the new IRBuilder API. ( rC323617 )
Step 4) Update Polly to use the new IRBuilder API. ( rL323618 )
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
and those that use use MemIntrinsicInst::[get|set]Alignment() to use [get|set]DestAlignment()
and [get|set]SourceAlignment() instead. (rL323886, rL323891, rL324148, rL324273, rL324278,
rL324384, rL324395, rL324402, rL324626, rL324642, rL324653, rL324654, rL324773, rL324774,
rL324781, rL324784 )
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
MemIntrinsicInst::[get|set]Alignment() methods.
Reference
http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
Reviewers: eugenis, bollu
Reviewed By: eugenis
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42710
llvm-svn: 324955
Summary:
Most DIExpressions are empty or very simple. When they are complex, they
tend to be unique, so checking them inline is reasonable.
This also avoids the need for CodeGen passes to append to the
llvm.dbg.mir named md node.
See also PR22780, for making DIExpression not be an MDNode.
Reviewers: aprantl, dexonsmith, dblaikie
Subscribers: qcolombet, javed.absar, eraman, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D37075
llvm-svn: 311594
There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.
rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951
llvm-svn: 309426
Summary:
This patch is part of 3 patches that together form a single patch, but must be introduced in stages in order not to break things.
The way that LLVM interprets DW_OP_plus in DIExpression nodes is basically that of the DW_OP_plus_uconst operator since LLVM expects an unsigned constant operand. This unnecessarily restricts the DW_OP_plus operator, preventing it from being used to describe the evaluation of runtime values on the expression stack. These patches try to align the semantics of DW_OP_plus and DW_OP_minus with that of the DWARF definition, which pops two elements off the expression stack, performs the operation and pushes the result back on the stack.
This is done in three stages:
• The first patch (LLVM) adds support for DW_OP_plus_uconst.
• The second patch (Clang) contains changes all its uses from DW_OP_plus to DW_OP_plus_uconst.
• The third patch (LLVM) changes the semantics of DW_OP_plus and DW_OP_minus to be in line with its DWARF meaning. This patch includes the bitcode upgrade from legacy DIExpressions.
Patch by Sander de Smalen.
Reviewers: echristo, pcc, aprantl
Reviewed By: aprantl
Subscribers: fhahn, javed.absar, aprantl, llvm-commits
Differential Revision: https://reviews.llvm.org/D33894
llvm-svn: 305386
The DWARF specification knows 3 kinds of non-empty simple location
descriptions:
1. Register location descriptions
- describe a variable in a register
- consist of only a DW_OP_reg
2. Memory location descriptions
- describe the address of a variable
3. Implicit location descriptions
- describe the value of a variable
- end with DW_OP_stack_value & friends
The existing DwarfExpression code is pretty much ignorant of these
restrictions. This used to not matter because we only emitted very
short expressions that we happened to get right by accident. This
patch makes DwarfExpression aware of the rules defined by the DWARF
standard and now chooses the right kind of location description for
each expression being emitted.
This would have been an NFC commit (for the existing testsuite) if not
for the way that clang describes captured block variables. Based on
how the previous code in LLVM emitted locations, DW_OP_deref
operations that should have come at the end of the expression are put
at its beginning. Fixing this means changing the semantics of
DIExpression, so this patch bumps the version number of DIExpression
and implements a bitcode upgrade.
There are two major changes in this patch:
I had to fix the semantics of dbg.declare for describing function
arguments. After this patch a dbg.declare always takes the *address*
of a variable as the first argument, even if the argument is not an
alloca.
When lowering a DBG_VALUE, the decision of whether to emit a register
location description or a memory location description depends on the
MachineLocation — register machine locations may get promoted to
memory locations based on their DIExpression. (Future) optimization
passes that want to salvage implicit debug location for variables may
do so by appending a DW_OP_stack_value. For example:
DBG_VALUE, [RBP-8] --> DW_OP_fbreg -8
DBG_VALUE, RAX --> DW_OP_reg0 +0
DBG_VALUE, RAX, DIExpression(DW_OP_deref) --> DW_OP_reg0 +0
All testcases that were modified were regenerated from clang. I also
added source-based testcases for each of these to the debuginfo-tests
repository over the last week to make sure that no synchronized bugs
slip in. The debuginfo-tests compile from source and run the debugger.
https://bugs.llvm.org/show_bug.cgi?id=32382
<rdar://problem/31205000>
Differential Revision: https://reviews.llvm.org/D31439
llvm-svn: 300522
The Fuchsia ABI defines slots from the thread pointer where the
stack-guard value for stack-protector, and the unsafe stack pointer
for safe-stack, are stored. This parallels the Android ABI support.
Patch by Roland McGrath
Differential Revision: https://reviews.llvm.org/D30237
llvm-svn: 296081
This is a fix for PR30318.
Clang may generate IR where an alloca is already live when entering a
BB with lifetime.start. In this case, conservatively extend the
alloca lifetime all the way back to the block entry.
llvm-svn: 281784
