[go] cmd/link: ignore mapping symbols on riscv64
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cmd/link: ignore mapping symbols on riscv64
Specified in RISC-V ELF psABI[1], mapping symbols are symbols starting with "$d" or "$x" with STT_NOTYPE, STB_LOCAL and zero sizes, indicating boundaries between code and data in the same section.
Let's simply ignore them as they're only markers instead of real symbols. This fixes linking errors like
sym#63 ("$d"): ignoring symbol in section 4 (".riscv.attributes") (type 0)
when using CGO together with Clang and internal linker, which are caused by unnecessary (but technically correct) mapping symbols created by LLVM for various sections.
Fixes #73591
[1]: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/87aecf601722171c570120a46003be3c17ad3108/riscv-elf.adoc?plain=1#L1448
Change diff
diff --git a/src/cmd/link/internal/loadelf/ldelf.go b/src/cmd/link/internal/loadelf/ldelf.go
index 9f251e7..c91fed5 100644
--- a/src/cmd/link/internal/loadelf/ldelf.go
+++ b/src/cmd/link/internal/loadelf/ldelf.go
@@ -602,6 +602,14 @@
// See https://sourceware.org/bugzilla/show_bug.cgi?id=21809
continue
}
+
+ if arch.Family == sys.RISCV64 &&
+ (strings.HasPrefix(elfsym.name, "$d") || strings.HasPrefix(elfsym.name, "$x")) {
+ // Ignore RISC-V mapping symbols, which
+ // are similar to ARM64's case.
+ // See issue 73591.
+ continue
+ }
}
if strings.HasPrefix(elfsym.name, ".Linfo_string") {
Change information
- M src/cmd/link/internal/loadelf/ldelf.go
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Gopher Robot (Gerrit)
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I spotted some possible problems.
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Yao Zi (Gerrit)
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I spotted some possible problems.
These findings are based on simple heuristics. If a finding appears wrong, briefly reply here saying so. Otherwise, please address any problems and update the GitHub PR. When complete, mark this comment as 'Done' and click the [blue 'Reply' button](https://go.dev/wiki/GerritBot#i-left-a-reply-to-a-comment-in-gerrit-but-no-one-but-me-can-see-it) above.
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2. It looks like you have a properly formated bug reference, but the convention is to put bug references at the bottom of the commit message, even if a bug is also mentioned in the body of the message.The commit title and commit message body come from the GitHub PR title and description, and must be edited in the GitHub web interface (not via git). For instructions, see [here](https://go.dev/wiki/GerritBot/#how-does-gerritbot-determine-the-final-commit-message). For guidelines on commit messages for the Go project, see [here](https://go.dev/doc/contribute#commit_messages).
(In general for Gerrit code reviews, the change author is expected to [log in to Gerrit](https://go-review.googlesource.com/login/) with a Gmail or other Google account and then close out each piece of feedback by marking it as 'Done' if implemented as suggested or otherwise reply to each review comment. See the [Review](https://go.dev/doc/contribute#review) section of the Contributing Guide for details.)
I've reordered the reference link and the Fixes line. For 2, I've reformatted the long lines, but would like to keep format of the error log (output of go) as is.
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Meng Zhuo (Gerrit)
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I think CL668516 has fixed this issue.
p.s. this CL missed `.comment` and `.riscv.attibutes`
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Yao Zi (Gerrit)
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I think CL668516 has fixed this issue.
p.s. this CL missed `.comment` and `.riscv.attibutes`
No, it does take .comment and .riscv.attributes into account, please take a look at the referred issue where the message shows symbols from the two sections. And this patch eliminates all of the errors.
IOW it will process all mapping symbols instead of only the ones in the two sections. Instead of hardcoding sections that may contain mapping symbols, I think it's the correct way to go.
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Meng Zhuo (Gerrit)
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3 comments
Yao ZiI think CL668516 has fixed this issue.
p.s. this CL missed `.comment` and `.riscv.attibutes`
No, it does take .comment and .riscv.attributes into account, please take a look at the referred issue where the message shows symbols from the two sections. And this patch eliminates all of the errors.
IOW it will process all mapping symbols instead of only the ones in the two sections. Instead of hardcoding sections that may contain mapping symbols, I think it's the correct way to go.
I see, I misread the `$x, a sequence of instructions.` part
LGTM, only the fix issue has been closed due to duplication. Please update the issue number in the commit message.
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Yao Zi (Gerrit)
Yao Zi added 1 comment![]( "Open in Gerrit")
Fixes #73591Yao Zi```suggestion
Fixes #73516
```
```suggestion
Fixes #73516
```
Thanks, I've updated the referred issue.
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Meng Zhuo (Gerrit)
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Change information
cmd/link: ignore mapping symbols on riscv64
Specified in RISC-V ELF psABI[1], mapping symbols are symbols starting
with "$d" or "$x" with STT_NOTYPE, STB_LOCAL and zero sizes, indicating
boundaries between code and data in the same section.
Let's simply ignore them as they're only markers instead of real symbols.
This fixes linking errors like
sym#63 ("$d"): ignoring symbol in section 4 (".riscv.attributes") (type 0)
when using CGO together with Clang and internal linker, which are caused
by unnecessary (but technically correct) mapping symbols created by LLVM
for various sections.
[1]: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/87aecf601722171c570120a46003be3c17ad3108/riscv-elf.adoc?plain=1#L1448
Fixes #73516
- M src/cmd/link/internal/loadelf/ldelf.go
Code-Review: +2 by Cherry Mui, +2 by Meng Zhuo, +1 by Michael Knyszek
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