[LLVM][Cygwin] Fix Signals compatibility with Cygwin API #138117
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Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
Member
|
@llvm/pr-subscribers-llvm-support Author: Mateusz Mikuła (mati865) ChangesCygwin types sometimes do not match Linux exactly. Like in this case: Casting here is safe and solves the issue. Split out from #134494 Full diff: https://github.com/llvm/llvm-project/pull/138117.diff 1 Files Affected:
diff --git a/llvm/lib/Support/Unix/Signals.inc b/llvm/lib/Support/Unix/Signals.inc
index 30e5f40193974..691e1014f18e8 100644
--- a/llvm/lib/Support/Unix/Signals.inc
+++ b/llvm/lib/Support/Unix/Signals.inc
@@ -847,7 +847,7 @@ void llvm::sys::PrintStackTrace(raw_ostream &OS, int Depth) {
const char *name = strrchr(dlinfo.dli_fname, '/');
if (!name)
- OS << format(" %-*s", width, dlinfo.dli_fname);
+ OS << format(" %-*s", width, static_cast<const char *>(dlinfo.dli_fname));
else
OS << format(" %-*s", width, name + 1);
|
Contributor
|
Unrelated to this PR, but they really should be checking the return value of dladdr a few lines above and not trying to use the DL_info struct in case of error. In Cygwin at least, it likely won't have written to dli_fname in that case. I'm not firm enough in the specs involved in this situation: in C I'd think you'd need to set the struct |
Member
That sounds like a quite reasonable fix. And I do think you would need to manually initialize a struct even in C++ if you want it to be zero initialized. |
Contributor
|
Cygwin's error path here (uninitialized buffer) is probably not any worse than Linux's (uninitialized pointer). After this is merged I can look at dealing with it (it'd likely conflict). The easiest thing would be to |
IanWood1
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to IanWood1/llvm-project
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May 6, 2025
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
GeorgeARM
pushed a commit
to GeorgeARM/llvm-project
that referenced
this pull request
May 7, 2025
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
jeremyd2019
pushed a commit
to jeremyd2019/llvm-project
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May 14, 2025
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
jeremyd2019
pushed a commit
to jeremyd2019/llvm-project
that referenced
this pull request
May 15, 2025
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
jeremyd2019
pushed a commit
to jeremyd2019/llvm-project
that referenced
this pull request
Jul 17, 2025
Cygwin types sometimes do not match Linux exactly. Like in this case:
```
In file included from /h/projects/llvm-project/llvm/include/llvm/Support/Error.h:23,
from /h/projects/llvm-project/llvm/include/llvm/Support/FileSystem.h:34,
from /h/projects/llvm-project/llvm/lib/Support/Signals.cpp:22:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h: In instantiation of ‘llvm::format_object<Ts>::format_object(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’:
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:126:10: required from ‘llvm::format_object<Ts ...> llvm::format(const char*, const Ts& ...) [with Ts = {int, char [4096]}]’
/h/projects/llvm-project/llvm/lib/Support/Unix/Signals.inc:850:19: required from here
/h/projects/llvm-project/llvm/include/llvm/Support/Format.h:106:34: error: no matching function for call to ‘std::tuple<int, char [4096]>::tuple(const int&, const char [4096])’
106 | : format_object_base(fmt), Vals(vals...) {
| ^~~~~~~~~~~~~
```
Casting here is safe and solves the issue.
tgymnich
pushed a commit
that referenced
this pull request
Oct 13, 2025
Cygwin builds are currently broken after #157312, which effectively reverted #138117. The root cause is that Cygwin defines `DL_info::dli_fname` as `char[N]`, which is not a valid parameter type for `llvm::format`. This patch allows `llvm::format` to accept `char[N]` by decaying it to `const char *`. As a result, string literals are also accepted without an explicit cast. Other array types remain rejected: - Wide/unicode character arrays (e.g., `wchar_t[N]`) are not supported, as LLVM does not use them and they are less compatible with platform's `printf` implementations. - Non-character arrays (e.g., `int[N]`) are also rejected, since passing such arrays to `printf` is meaningless.
DharuniRAcharya
pushed a commit
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that referenced
this pull request
Oct 13, 2025
…9541) Cygwin builds are currently broken after llvm#157312, which effectively reverted llvm#138117. The root cause is that Cygwin defines `DL_info::dli_fname` as `char[N]`, which is not a valid parameter type for `llvm::format`. This patch allows `llvm::format` to accept `char[N]` by decaying it to `const char *`. As a result, string literals are also accepted without an explicit cast. Other array types remain rejected: - Wide/unicode character arrays (e.g., `wchar_t[N]`) are not supported, as LLVM does not use them and they are less compatible with platform's `printf` implementations. - Non-character arrays (e.g., `int[N]`) are also rejected, since passing such arrays to `printf` is meaningless.
akadutta
pushed a commit
to akadutta/llvm-project
that referenced
this pull request
Oct 14, 2025
…9541) Cygwin builds are currently broken after llvm#157312, which effectively reverted llvm#138117. The root cause is that Cygwin defines `DL_info::dli_fname` as `char[N]`, which is not a valid parameter type for `llvm::format`. This patch allows `llvm::format` to accept `char[N]` by decaying it to `const char *`. As a result, string literals are also accepted without an explicit cast. Other array types remain rejected: - Wide/unicode character arrays (e.g., `wchar_t[N]`) are not supported, as LLVM does not use them and they are less compatible with platform's `printf` implementations. - Non-character arrays (e.g., `int[N]`) are also rejected, since passing such arrays to `printf` is meaningless.
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Cygwin types sometimes do not match Linux exactly. Like in this case:
Casting here is safe and solves the issue.
Split out from #134494