[lld][ELF] Introduce an option to keep data section prefix. #148985
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@@ -103,13 +103,48 @@ StringRef LinkerScript::getOutputSectionName(const InputSectionBase *s) const { | |
| return ".text"; | ||
| } | ||
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| // When zKeepDataSectionPrefix is true, keep .hot and .unlikely suffixes | ||
| // in data sections. | ||
| static constexpr StringRef dataSectionPrefixes[] = { | ||
| ".data.rel.ro", ".data", ".rodata", ".bss.rel.ro", ".bss", | ||
| }; | ||
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| for (auto [index, v] : llvm::enumerate(dataSectionPrefixes)) { | ||
| StringRef secName = s->name; | ||
| if (!secName.consume_front(v)) | ||
| continue; | ||
| if (!secName.empty() && secName[0] != '.') { | ||
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| continue; | ||
| } | ||
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| // The section name starts with 'v', and the remaining string is either | ||
| // empty or starts with a '.' character. If keep-data-section-prefix is | ||
| // false, map s to output section with name 'v'. | ||
| if (!ctx.arg.zKeepDataSectionPrefix) | ||
| return v; | ||
| // Preserve .hot or .unlikely suffixes in data sections with | ||
| // keep-data-section-prefix=true. | ||
| if (isSectionPrefix(".hot", secName)) | ||
| return s->name.substr(0, v.size() + 4); | ||
| if (isSectionPrefix(".unlikely", secName)) | ||
| return s->name.substr(0, v.size() + 9); | ||
| if (index == 2) { | ||
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| // Place input .rodata.str<N>.hot. or .rodata.cst<N>.hot. into the | ||
| // .rodata.hot section. | ||
| if (s->name.ends_with(".hot.")) | ||
| return ".rodata.hot"; | ||
| // Place input .rodata.str<N>.hot. or .rodata.cst<N>.unlikely. into the | ||
| // .rodata.unlikely section. | ||
| if (s->name.ends_with(".unlikely.")) | ||
| return ".rodata.unlikely"; | ||
| } | ||
| return v; | ||
| } | ||
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| for (StringRef v : | ||
| {".ldata", ".lrodata", ".lbss", ".gcc_except_table", ".init_array", | ||
| ".fini_array", ".tbss", ".tdata", ".ARM.exidx", ".ARM.extab", ".ctors", | ||
| ".dtors", ".sbss", ".sdata", ".srodata"}) | ||
| if (isSectionPrefix(v, s->name)) | ||
| return v; | ||
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With the recent LLVM change that uses
.data.rel.ro.hot.(the.afterhotis mandatory), can this be simplified?There was a problem hiding this comment.
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The two ifs before
if (!ctx.arg.zKeepDataSectionPrefix)applies on the general cases, and there may not be a trailing dot to data sections. For instance, https://gcc.godbolt.org/z/G77P8n6qf compiles a simple source code with-O2 -ffunction-sections -fdata-sections, and var section name is.section .bss.var(without trailing dot).