release/20.x: [ELF] --package-metadata: support %[0-9a-fA-F][0-9a-fA-F]

[llvmbot]

Backport 0a470a9

Requested by: @MaskRay

[llvmbot]

@smithp35 What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-lld-elf

@llvm/pr-subscribers-lld

Author: None (llvmbot)

Changes

Backport 0a470a9

Requested by: @MaskRay

---

Full diff: https://github.com/llvm/llvm-project/pull/126549.diff

5 Files Affected:

• (modified) lld/ELF/Config.h (+1-1)
• (modified) lld/ELF/Driver.cpp (+22-1)
• (modified) lld/ELF/Options.td (+1-1)
• (modified) lld/docs/ld.lld.1 (+4)
• (modified) lld/test/ELF/package-metadata.s (+15-5)

diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index c2aadb2cef5200f..98e52b52ea46a11 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -407,7 +407,7 @@ struct Config {
   StringRef thinLTOJobs;
   unsigned timeTraceGranularity;
   int32_t splitStackAdjustSize;
-  StringRef packageMetadata;
+  SmallVector<uint8_t, 0> packageMetadata;
 
   // The following config options do not directly correspond to any
   // particular command line options.
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 9d0c992c1e85164..2d8a5ade2fecee5 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -822,6 +822,26 @@ static ICFLevel getICF(opt::InputArgList &args) {
   return ICFLevel::All;
 }
 
+static void parsePackageMetadata(Ctx &ctx, const opt::Arg &arg) {
+  unsigned c0, c1;
+  SmallVector<uint8_t, 0> decoded;
+  StringRef s = arg.getValue();
+  for (size_t i = 0, e = s.size(); i != e; ++i) {
+    if (s[i] != '%') {
+      decoded.push_back(s[i]);
+    } else if (i + 2 < e && (c1 = hexDigitValue(s[i + 1])) != -1u &&
+               (c0 = hexDigitValue(s[i + 2])) != -1u) {
+      decoded.push_back(uint8_t(c1 * 16 + c0));
+      i += 2;
+    } else {
+      ErrAlways(ctx) << arg.getSpelling() << ": invalid % escape at byte " << i
+                     << "; supports only %[0-9a-fA-F][0-9a-fA-F]";
+      return;
+    }
+  }
+  ctx.arg.packageMetadata = std::move(decoded);
+}
+
 static StripPolicy getStrip(Ctx &ctx, opt::InputArgList &args) {
   if (args.hasArg(OPT_relocatable))
     return StripPolicy::None;
@@ -1383,7 +1403,8 @@ static void readConfigs(Ctx &ctx, opt::InputArgList &args) {
   ctx.arg.optimize = args::getInteger(args, OPT_O, 1);
   ctx.arg.orphanHandling = getOrphanHandling(ctx, args);
   ctx.arg.outputFile = args.getLastArgValue(OPT_o);
-  ctx.arg.packageMetadata = args.getLastArgValue(OPT_package_metadata);
+  if (auto *arg = args.getLastArg(OPT_package_metadata))
+    parsePackageMetadata(ctx, *arg);
   ctx.arg.pie = args.hasFlag(OPT_pie, OPT_no_pie, false);
   ctx.arg.printIcfSections =
       args.hasFlag(OPT_print_icf_sections, OPT_no_print_icf_sections, false);
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
index c31875305952fb2..d9998176d0dd407 100644
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -565,7 +565,7 @@ def z: JoinedOrSeparate<["-"], "z">, MetaVarName<"<option>">,
 def visual_studio_diagnostics_format : FF<"vs-diagnostics">,
 HelpText<"Format diagnostics for Visual Studio compatibility">;
 
-def package_metadata: JJ<"package-metadata=">, HelpText<"Emit package metadata note">;
+def package_metadata: JJ<"package-metadata=">, HelpText<"Emit a percent-encoded string to the .note.package section">;
 
 // Aliases
 def: Separate<["-"], "dT">, Alias<default_script>, HelpText<"Alias for --default-script">;
diff --git a/lld/docs/ld.lld.1 b/lld/docs/ld.lld.1
index b28c6082f68b091..b5c1816ce6e5fde 100644
--- a/lld/docs/ld.lld.1
+++ b/lld/docs/ld.lld.1
@@ -493,6 +493,10 @@ If
 .Fl -use-android-relr-tags
 is specified, use SHT_ANDROID_RELR instead of SHT_RELR.
 .Pp
+.It Fl -package-metadata
+Emit a percent-encoded string to the
+.Cm .note.package
+section. For example, %25 decodes to a single %.
 .It Fl -pic-veneer
 Always generate position independent thunks.
 .It Fl -pie , Fl -pic-executable
diff --git a/lld/test/ELF/package-metadata.s b/lld/test/ELF/package-metadata.s
index 29df499d7e98d29..a70a8940d7c68bb 100644
--- a/lld/test/ELF/package-metadata.s
+++ b/lld/test/ELF/package-metadata.s
@@ -1,12 +1,15 @@
 # REQUIRES: x86
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 a.s -o a.o
 
-# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+# RUN: ld.lld a.o --package-metadata='{}'
+# RUN: llvm-readelf -n a.out | FileCheck %s --check-prefixes=NOTE,FIRST
 
-# RUN: ld.lld %t.o -o %t --package-metadata='{}'
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,FIRST
+# RUN: ld.lld a.o --package-metadata='{"abc":123}'
+# RUN: llvm-readelf -n a.out | FileCheck %s --check-prefixes=NOTE,SECOND
 
-# RUN: ld.lld %t.o -o %t --package-metadata='{"abc":123}'
-# RUN: llvm-readelf -n %t | FileCheck %s --check-prefixes=NOTE,SECOND
+# RUN: ld.lld a.o --package-metadata='%7b%22abc%22:123%7D'
+# RUN: llvm-readelf -n a.out | FileCheck %s --check-prefixes=NOTE,SECOND
 
 # NOTE: .note.package
 # NOTE-NEXT: Owner
@@ -14,6 +17,13 @@
 # FIRST-NEXT: description data: 7b 7d 00
 # SECOND-NEXT: description data: 7b 22 61 62 63 22 3a 31 32 33 7d 00
 
+# RUN: not ld.lld a.o --package-metadata='%7b%' 2>&1 | FileCheck %s --check-prefix=ERR
+# RUN: not ld.lld a.o --package-metadata='%7b%7' 2>&1 | FileCheck %s --check-prefix=ERR
+# RUN: not ld.lld a.o --package-metadata='%7b%7g' 2>&1 | FileCheck %s --check-prefix=ERR
+
+# ERR: error: --package-metadata=: invalid % escape at byte 3; supports only %[0-9a-fA-F][0-9a-fA-F]
+
+#--- a.s
 .globl _start
 _start:
   ret

[smithp35]

LGTM. This would be useful as it would be needed if Linux Distros start using this.

[github-actions]

@MaskRay (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.