We can't consider variable safe if out-of-lifetime access is possible.
So if StackLifetime can't prove that the instruction always uses
the variable when it's still alive, we consider it unsafe.
Usually DominatorTree provides this info, but here we use
StackLifetime. The reason is that in the next patch StackLifetime
will be used for actual lifetime checks and we can avoid
forwarding the DominatorTree into this code.
Code does not track terminators and do not expose them through interface.
State there is just a state of the last instruction or entry.
So this information is just redundant and doesn't need to be tested.
Summary:
Extend StackLifetime with option to calculate liveliness
where alloca is only considered alive on basic block entry
if all non-dead predecessors had it alive at terminators.
Depends on D82043.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82124
Summary:
ThinLTO linking runs dataflow processing on collected
function parameters. Then StackSafetyGlobalInfoWrapperPass
in ThinLTO backend will run as usual looking up to external
symbol in the summary if needed.
Depends on D80985.
Reviewers: eugenis, pcc
Reviewed By: eugenis
Subscribers: inglorion, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D81242
We don't need process paramenters which marked as
byval as we are not going to pass interested allocas
without copying.
If we pass value into byval argument, we just handle that
as Load of corresponding type and stop that branch of analysis.
This lets us to remove !stack-safe metadata and
better controll when to perform StackSafety
analysis.
Reviewers: eugenis
Subscribers: hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D80771
We need to process only parameters. Allocas access can be calculated
afterwards.
Also don't create fake function for aliases and just resolve them on
initialization.
Summary:
Run StackSafetyAnalysis at the end of the IR pipeline and annotate
proven safe allocas with !stack-safe metadata. Do not instrument such
allocas in the AArch64StackTagging pass.
Reviewers: pcc, vitalybuka, ostannard
Reviewed By: vitalybuka
Subscribers: merge_guards_bot, kristof.beyls, hiraditya, cfe-commits, gilang, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D73513
Summary:
Treat scalable allocas as if they have storage size of 0, and
scalable-typed memory accesses as if their range is unlimited.
This is not a proper support of scalable vector types in the analysis -
we can do better, but not today.
Reviewers: vitalybuka
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73394
Summary:
IPA is implemented as module pass which produce map from Function or Alias to
StackSafetyInfo for a single function.
From prototype by Evgenii Stepanov and Vlad Tsyrklevich.
Reviewers: eugenis, vlad.tsyrklevich, pcc, glider
Subscribers: hiraditya, mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D54543
llvm-svn: 347611
Summary:
Analysis produces StackSafetyInfo which contains information with how allocas
and parameters were used in functions.
From prototype by Evgenii Stepanov and Vlad Tsyrklevich.
Reviewers: eugenis, vlad.tsyrklevich, pcc, glider
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D54504
llvm-svn: 347603
Vitaly Buka