Add Natvis visualiser and debuginfo tests for `f128` by beetrees · Pull Request #161777 · rust-lang/rust

beetrees · 2026-08-25T17:40:38Z

To render f128s in debuggers on MSVC targets, this PR changes the compiler to output f128s as struct f128 { low_bits: u64, high_bits: u64 }, and includes a Natvis visualiser that displays the float in hexdecimal format (similar to the LowerHex impl in #160626), as unlike f16 there's no larger supported float format to convert to and trying to write a float to decimal string converter in Natvis didn't seem practical. gdb, lldb and cdb tests are also included for f128, although gdb does not yet correctly identify the float format.

I did consider also displaying a double approximation of the f128 (as the debugger will convert that to a decimal string) but decided against it as f64 has a significantly smaller exponent range too (meaning very large or small f128s couldn't have an approximation anyway) and cdb and WinDbg both seem to round all floating-point numbers to 6 decimal places, meaning the displayed number is (double) rounded even further than f64 precision and is useless for tiny values.

Closes #121837
Tracking issue: #116909

rustbot · 2026-08-25T19:20:19Z

r? @JohnTitor

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beetrees · 2026-08-25T19:22:21Z

cc MSVC target maintainers: @ChrisDenton @dpaoliello @Fulgen301 @lambdageek @sivadeilra @wesleywiser

beetrees · 2026-08-25T19:29:06Z

(Given this touches debuginfo tests this should probably get a bors try x86_64-msvc-* i686-msvc-* aarch64-msvc-* aarch64-apple-*.)

folkertdev · 2026-08-25T19:57:23Z

@bors try jobs=x86_64-msvc-,i686-msvc-,aarch64-msvc-,aarch64-apple-

folkertdev · 2026-08-25T19:58:06Z

@bors try jobs=x86_64-msvc-,i686-msvc-,aarch64-msvc-,aarch64-apple-

Add Natvis visualiser and debuginfo tests for `f128` try-job: x86_64-msvc-* try-job: i686-msvc-* try-job: aarch64-msvc-* try-job: aarch64-apple-*

rust-bors · 2026-08-25T23:07:38Z

💔 Test for 816a2f0 failed: CI. Failed jobs:

try - aarch64-apple-1 (web logs, enhanced plaintext logs)
try - aarch64-apple-macos-26-1 (web logs, enhanced plaintext logs)

beetrees · 2026-08-26T10:07:31Z

According to the table on Wikipedia, there isn't any Xcode versions yet with LLDB 22 or later, so I've ignored the f128 debuginfo tests on Apple for now and left a FIXME.

folkertdev · 2026-08-26T10:08:43Z

@bors try jobs=x86_64-msvc-,i686-msvc-,aarch64-msvc-,aarch64-apple-

Add Natvis visualiser and debuginfo tests for `f128` try-job: x86_64-msvc-* try-job: i686-msvc-* try-job: aarch64-msvc-* try-job: aarch64-apple-*

rust-bors · 2026-08-26T12:56:44Z

☀️ Try build successful (CI)
Build commit: d79cce8 (d79cce855e6f305d9b8796f97b79e09fb0a5c022)
Base parent: 3ffb26f (3ffb26fbf5bf232cf59e314e75ea325973f4f583)

beetrees · 2026-08-26T14:40:08Z

@rustbot review

JohnTitor

Looks good! I'm not going to r+ just in case you want to wait for another look from the target maintainers. Ohterwise r=me

View changes since this review

Add Natvis visualiser and debuginfo tests for `f128` To render f128s in debuggers on MSVC targets, this PR changes the compiler to output `f128`s as `struct f128 { low_bits: u64, high_bits: u64 }`, and includes a Natvis visualiser that displays the float in hexdecimal format (similar to the `LowerHex` impl in rust-lang#160626), as unlike `f16` there's no larger supported float format to convert to and trying to write a float to decimal string converter in Natvis didn't seem practical. gdb, lldb and cdb tests are also included for `f128`, although gdb does not yet correctly identify the float format. I did consider also displaying a `double` approximation of the `f128` (as the debugger will convert that to a decimal string) but decided against it as `f64` has a significantly smaller exponent range too (meaning very large or small `f128`s couldn't have an approximation anyway) and `cdb` and `WinDbg` both seem to round all floating-point numbers to 6 decimal places, meaning the displayed number is (double) rounded even further than `f64` precision and is useless for tiny values. Closes rust-lang#121837 Tracking issue: rust-lang#116909

…uwer Rollup of 15 pull requests Successful merges: - #160401 (sparc: make ABI consistent with clang) - #161777 (Add Natvis visualiser and debuginfo tests for `f128`) - #162423 (Rename the src install build step to rust-src.) - #162740 (stdarch subtree update) - #162824 (link Enzyme and the offload with in-tree lld if possible) - #162832 (add `Div` and `Mul` for `Complex<{float}>`) - #161005 (fix: unfulfilled nested dead code lint) - #161803 (Fix docs of make_ascii_lowercase/make_ascii_upercase) - #162256 (Add mentions to sync back `RELEASES.md` to the `main` branch) - #162661 (simplify `Target::GenericParam`) - #162666 (Tidy footnote in `platform-support.md`) - #162803 (docs(num): add documentation for `NonZero::from_str`) - #162906 (Move more `rustdoc-html` tests in the right location) - #162922 (An assortment of polonius tweaks) - #162930 (Use niche length type for strlen to guarantee `isize::MAX` bound)

Add Natvis visualiser and debuginfo tests for `f128` To render f128s in debuggers on MSVC targets, this PR changes the compiler to output `f128`s as `struct f128 { low_bits: u64, high_bits: u64 }`, and includes a Natvis visualiser that displays the float in hexdecimal format (similar to the `LowerHex` impl in rust-lang#160626), as unlike `f16` there's no larger supported float format to convert to and trying to write a float to decimal string converter in Natvis didn't seem practical. gdb, lldb and cdb tests are also included for `f128`, although gdb does not yet correctly identify the float format. I did consider also displaying a `double` approximation of the `f128` (as the debugger will convert that to a decimal string) but decided against it as `f64` has a significantly smaller exponent range too (meaning very large or small `f128`s couldn't have an approximation anyway) and `cdb` and `WinDbg` both seem to round all floating-point numbers to 6 decimal places, meaning the displayed number is (double) rounded even further than `f64` precision and is useless for tiny values. Closes rust-lang#121837 Tracking issue: rust-lang#116909

…uwer Rollup of 15 pull requests Successful merges: - #160401 (sparc: make ABI consistent with clang) - #161777 (Add Natvis visualiser and debuginfo tests for `f128`) - #162423 (Rename the src install build step to rust-src.) - #162740 (stdarch subtree update) - #162824 (link Enzyme and the offload with in-tree lld if possible) - #161005 (fix: unfulfilled nested dead code lint) - #161803 (Fix docs of make_ascii_lowercase/make_ascii_upercase) - #162256 (Add mentions to sync back `RELEASES.md` to the `main` branch) - #162661 (simplify `Target::GenericParam`) - #162666 (Tidy footnote in `platform-support.md`) - #162803 (docs(num): add documentation for `NonZero::from_str`) - #162906 (Move more `rustdoc-html` tests in the right location) - #162922 (An assortment of polonius tweaks) - #162929 (Update unicode_data to Unicode version 18.0.0) - #162930 (Use niche length type for strlen to guarantee `isize::MAX` bound)

Add Natvis visualiser and debuginfo tests for `f128` To render f128s in debuggers on MSVC targets, this PR changes the compiler to output `f128`s as `struct f128 { low_bits: u64, high_bits: u64 }`, and includes a Natvis visualiser that displays the float in hexdecimal format (similar to the `LowerHex` impl in rust-lang#160626), as unlike `f16` there's no larger supported float format to convert to and trying to write a float to decimal string converter in Natvis didn't seem practical. gdb, lldb and cdb tests are also included for `f128`, although gdb does not yet correctly identify the float format. I did consider also displaying a `double` approximation of the `f128` (as the debugger will convert that to a decimal string) but decided against it as `f64` has a significantly smaller exponent range too (meaning very large or small `f128`s couldn't have an approximation anyway) and `cdb` and `WinDbg` both seem to round all floating-point numbers to 6 decimal places, meaning the displayed number is (double) rounded even further than `f64` precision and is useless for tiny values. Closes rust-lang#121837 Tracking issue: rust-lang#116909

…uwer Rollup of 14 pull requests Successful merges: - #160401 (sparc: make ABI consistent with clang) - #161777 (Add Natvis visualiser and debuginfo tests for `f128`) - #162740 (stdarch subtree update) - #162824 (link Enzyme and the offload with in-tree lld if possible) - #161005 (fix: unfulfilled nested dead code lint) - #161803 (Fix docs of make_ascii_lowercase/make_ascii_upercase) - #162256 (Add mentions to sync back `RELEASES.md` to the `main` branch) - #162661 (simplify `Target::GenericParam`) - #162666 (Tidy footnote in `platform-support.md`) - #162803 (docs(num): add documentation for `NonZero::from_str`) - #162906 (Move more `rustdoc-html` tests in the right location) - #162922 (An assortment of polonius tweaks) - #162929 (Update unicode_data to Unicode version 18.0.0) - #162930 (Use niche length type for strlen to guarantee `isize::MAX` bound)

JonathanBrouwer · 2026-09-18T17:27:52Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #162973 (comment)

rust-bors · 2026-09-18T17:27:59Z

This pull request was unapproved.

This PR was contained in a rollup (#162973), which was unapproved.

View changes since this unapproval

rust-bors · 2026-09-18T18:05:12Z

⚠️ A new commit b7bad07da0564a861c8ffcbeb290d4409f5cb937 was pushed.

This PR was contained in a rollup (#162973), which was closed.

beetrees · 2026-09-18T18:14:09Z

Test fails locally on i686-unknown-linux-gnu - I think GDB can't find any 16-byte float type to represent it internally so can't even display the DWARF type name. Since GDB doesn't have proper f128 support yet and the type names working is more of a coincidence, I've replaced the failing checks with FIXMEs.

@bors try jobs=test-i686-gnu-nopt-1

Add Natvis visualiser and debuginfo tests for `f128` try-job: test-i686-gnu-nopt-1

rust-bors · 2026-09-18T19:57:20Z

☀️ Try build successful (CI)
Build commit: fd84d0d (fd84d0de4842e4d20e8d41134ffe0b41ef0060c6)
Base parent: 420ed2a (420ed2a0c3d7225b1744266fd884d431b4d8cfe0)

beetrees · 2026-09-18T20:33:37Z

@rustbot review

JohnTitor · 2026-09-19T00:53:02Z

@bors r+

rust-bors · 2026-09-19T00:53:05Z

📌 Commit b7bad07 has been approved by JohnTitor

It is now in the queue for this repository.

Add Natvis visualiser and debuginfo tests for `f128` To render f128s in debuggers on MSVC targets, this PR changes the compiler to output `f128`s as `struct f128 { low_bits: u64, high_bits: u64 }`, and includes a Natvis visualiser that displays the float in hexdecimal format (similar to the `LowerHex` impl in rust-lang#160626), as unlike `f16` there's no larger supported float format to convert to and trying to write a float to decimal string converter in Natvis didn't seem practical. gdb, lldb and cdb tests are also included for `f128`, although gdb does not yet correctly identify the float format. I did consider also displaying a `double` approximation of the `f128` (as the debugger will convert that to a decimal string) but decided against it as `f64` has a significantly smaller exponent range too (meaning very large or small `f128`s couldn't have an approximation anyway) and `cdb` and `WinDbg` both seem to round all floating-point numbers to 6 decimal places, meaning the displayed number is (double) rounded even further than `f64` precision and is useless for tiny values. Closes rust-lang#121837 Tracking issue: rust-lang#116909

beetrees force-pushed the f128-debuginfo branch from b68bc57 to e9dc1bb Compare August 25, 2026 17:56

beetrees marked this pull request as ready for review August 25, 2026 19:20

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Auto merge of #161777 - beetrees:f128-debuginfo, r=<try>

816a2f0

Add Natvis visualiser and debuginfo tests for `f128` try-job: x86_64-msvc-* try-job: i686-msvc-* try-job: aarch64-msvc-* try-job: aarch64-apple-*

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beetrees force-pushed the f128-debuginfo branch from e9dc1bb to 19f719c Compare August 26, 2026 10:06

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Auto merge of #161777 - beetrees:f128-debuginfo, r=<try>

d79cce8

Add Natvis visualiser and debuginfo tests for `f128` try-job: x86_64-msvc-* try-job: i686-msvc-* try-job: aarch64-msvc-* try-job: aarch64-apple-*

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JonathanBrouwer mentioned this pull request Sep 18, 2026

Rollup of 11 pull requests #162943

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JonathanBrouwer mentioned this pull request Sep 18, 2026

Rollup of 15 pull requests #162951

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Rollup of 15 pull requests #162954

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Rollup of 14 pull requests #162973

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Add Natvis visualiser and debuginfo tests for f128

b7bad07

beetrees force-pushed the f128-debuginfo branch from 167c7bd to b7bad07 Compare September 18, 2026 18:05

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Auto merge of #161777 - beetrees:f128-debuginfo, r=<try>

fd84d0d

Add Natvis visualiser and debuginfo tests for `f128` try-job: test-i686-gnu-nopt-1

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Zalathar mentioned this pull request Sep 19, 2026

Rollup of 18 pull requests #162996

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