[BOLT][NFC] Clarify requirement of PLTCall pass

[bgergely0]

PLTCall does not depend on linking the input with -znow: it sets the
DF_BIND_NOW and/or DF_1_NOW tags for the output binary.
The requirement is that the input contains either FLAGS or FLAGS_1
dynamic entries.

[bgergely0]

• [BOLT][NFC] Clarify requirement of PLTCall pass #164280 👈 (View in Graphite)
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[llvmbot]

@llvm/pr-subscribers-bolt

Author: Gergely Bálint (bgergely0)

Changes

PLTCall does not depend on linking the input with -znow: it sets the
DF_BIND_NOW and/or DF_1_NOW tags for the output binary.
The requirement is that the input contains either FLAGS or FLAGS_1
dynamic entries.

---

Full diff: https://github.com/llvm/llvm-project/pull/164280.diff

1 Files Affected:

• (modified) bolt/lib/Passes/PLTCall.cpp (+1-1)

diff --git a/bolt/lib/Passes/PLTCall.cpp b/bolt/lib/Passes/PLTCall.cpp
index 90b5f586a7bad..db0e8f93f80ee 100644
--- a/bolt/lib/Passes/PLTCall.cpp
+++ b/bolt/lib/Passes/PLTCall.cpp
@@ -23,7 +23,7 @@ namespace opts {
 extern cl::OptionCategory BoltOptCategory;
 
 static cl::opt<bolt::PLTCall::OptType>
-    PLT("plt", cl::desc("optimize PLT calls (requires linking with -znow)"),
+    PLT("plt", cl::desc("optimize PLT calls (sets DF_BIND_NOW/DF_1_NOW in the output binary)"),
         cl::init(bolt::PLTCall::OT_NONE),
         cl::values(clEnumValN(bolt::PLTCall::OT_NONE, "none",
                               "do not optimize PLT calls"),

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[bgergely0]

Not the most important PR, but it took me some time to understand why PLTCall works on a non-znow-linked input I tried, so I thought it adds some value.