By default, clang assumes that all trailing array objects could be a
FAM. So, an array of undefined size, size 0, size 1, or even size 42 is
considered as FAMs for optimizations at least.
One needs to override the default behavior by supplying the
`-fstrict-flex-arrays=<N>` flag, with `N > 0` value to reduce the set of
FAM candidates. Value `3` is the most restrictive and `0` is the most
permissive on this scale.
0: all trailing arrays are FAMs
1: only incomplete, zero and one-element arrays are FAMs
2: only incomplete, zero-element arrays are FAMs
3: only incomplete arrays are FAMs
If the user is happy with consdering single-element arrays as FAMs, they
just need to remove the
`consider-single-element-arrays-as-flexible-array-members` from the
command line.
Otherwise, if they don't want to recognize such cases as FAMs, they
should specify `-fstrict-flex-arrays` anyway, which will be picked up by
CSA.
Any use of the deprecated analyzer-config value will trigger a warning
explaining what to use instead.
The `-analyzer-config-help` is updated accordingly.
Depends on D138657
Reviewed By: xazax.hun
Differential Revision: https://reviews.llvm.org/D138659
As proposed in D126215 (ffe7950ebc62380c3afc7c71f454a1db3f6f5c76),
I'm dropping the `-analyzer-store` and
`-analyzer-opt-analyze-nested-blocks` clang frontend flags.
I'm also dropping the corresponding commandline handlers of `scanbuild`.
This behavior is planned to be part of `clang-16`.
Reviewed By: xazax.hun
Differential Revision: https://reviews.llvm.org/D132289
It was previously reverted by 8406839d1926486de900c7cabeea9f841bd3edf2.
---
This flag was introduced by
6818991d71
commit 6818991d7165f68fe196922d9e5c6648dd57cc47
Author: Ted Kremenek <kremenek@apple.com>
Date: Mon Dec 7 22:06:12 2009 +0000
Add clang-cc option '-analyzer-opt-analyze-nested-blocks' to treat
block literals as an entry point for analyzer checks.
The last reference was removed by this commit:
5c32dfc5fb
commit 5c32dfc5fb1cfcff8ae3671284e17daa8da3a188
Author: Anna Zaks <ganna@apple.com>
Date: Fri Dec 21 01:19:15 2012 +0000
[analyzer] Add blocks and ObjC messages to the call graph.
This paves the road for constructing a better function dependency graph.
If we analyze a function before the functions it calls and inlines,
there is more opportunity for optimization.
Note, we add call edges to the called methods that correspond to
function definitions (declarations with bodies).
Consequently, we should remove this dead flag.
However, this arises a couple of burning questions.
- Should the `cc1` frontend still accept this flag - to keep
tools/users passing this flag directly to `cc1` (which is unsupported,
unadvertised) working.
- If we should remain backward compatible, how long?
- How can we get rid of deprecated and obsolete flags at some point?
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D126067
I'm trying to remove unused options from the `Analyses.def` file, then
merge the rest of the useful options into the `AnalyzerOptions.def`.
Then make sure one can set these by an `-analyzer-config XXX=YYY` style
flag.
Then surface the `-analyzer-config` to the `clang` frontend;
After all of this, we can pursue the tablegen approach described
https://discourse.llvm.org/t/rfc-tablegen-clang-static-analyzer-engine-options-for-better-documentation/61488
In this patch, I'm proposing flag deprecations.
We should support deprecated analyzer flags for exactly one release. In
this case I'm planning to drop this flag in `clang-16`.
In the clang frontend, now we won't pass this option to the cc1
frontend, rather emit a warning diagnostic reminding the users about
this deprecated flag, which will be turned into error in clang-16.
Unfortunately, I had to remove all the tests referring to this flag,
causing a mass change. I've also added a test for checking this warning.
I've seen that `scan-build` also uses this flag, but I think we should
remove that part only after we turn this into a hard error.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D126215
This reverts commit d50d9946d1d7e5f20881f0bc71fbd025040b1c96.
Broke check-clang, see comments on https://reviews.llvm.org/D126067
Also revert dependent change "[analyzer] Deprecate the unused 'analyzer-opt-analyze-nested-blocks' cc1 flag"
This reverts commit 07b4a6d0461fe64e10d30029ed3d598e49ca3810.
Also revert "[analyzer] Fix buildbots after introducing a new frontend warning"
This reverts commit 90374df15ddc58d823ca42326a76f58e748f20eb.
(See https://reviews.llvm.org/rG90374df15ddc58d823ca42326a76f58e748f20eb)
This flag was introduced by
6818991d71
commit 6818991d7165f68fe196922d9e5c6648dd57cc47
Author: Ted Kremenek <kremenek@apple.com>
Date: Mon Dec 7 22:06:12 2009 +0000
Add clang-cc option '-analyzer-opt-analyze-nested-blocks' to treat
block literals as an entry point for analyzer checks.
The last reference was removed by this commit:
5c32dfc5fb
commit 5c32dfc5fb1cfcff8ae3671284e17daa8da3a188
Author: Anna Zaks <ganna@apple.com>
Date: Fri Dec 21 01:19:15 2012 +0000
[analyzer] Add blocks and ObjC messages to the call graph.
This paves the road for constructing a better function dependency graph.
If we analyze a function before the functions it calls and inlines,
there is more opportunity for optimization.
Note, we add call edges to the called methods that correspond to
function definitions (declarations with bodies).
Consequently, we should remove this dead flag.
However, this arises a couple of burning questions.
- Should the `cc1` frontend still accept this flag - to keep
tools/users passing this flag directly to `cc1` (which is unsupported,
unadvertised) working.
- If we should remain backward compatible, how long?
- How can we get rid of deprecated and obsolete flags at some point?
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D126067
I'm trying to remove unused options from the `Analyses.def` file, then
merge the rest of the useful options into the `AnalyzerOptions.def`.
Then make sure one can set these by an `-analyzer-config XXX=YYY` style
flag.
Then surface the `-analyzer-config` to the `clang` frontend;
After all of this, we can pursue the tablegen approach described
https://discourse.llvm.org/t/rfc-tablegen-clang-static-analyzer-engine-options-for-better-documentation/61488
In this patch, I'm proposing flag deprecations.
We should support deprecated analyzer flags for exactly one release. In
this case I'm planning to drop this flag in `clang-16`.
In the clang frontend, now we won't pass this option to the cc1
frontend, rather emit a warning diagnostic reminding the users about
this deprecated flag, which will be turned into error in clang-16.
Unfortunately, I had to remove all the tests referring to this flag,
causing a mass change. I've also added a test for checking this warning.
I've seen that `scan-build` also uses this flag, but I think we should
remove that part only after we turn this into a hard error.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D126215
