[llvm] 13e563e - [NFCI][StaticDataLayout] Get rid of section prefix validation in codegen (#162349)

[via llvm-commits]

Author: Mingming Liu
Date: 2025-10-13T19:02:53Z
New Revision: 13e563e5c60d9d71f8807477b6ecf555037a35bc

URL: https://github.com/llvm/llvm-project/commit/13e563e5c60d9d71f8807477b6ecf555037a35bc
DIFF: https://github.com/llvm/llvm-project/commit/13e563e5c60d9d71f8807477b6ecf555037a35bc.diff

LOG: [NFCI][StaticDataLayout] Get rid of section prefix validation in codegen (#162349)

The section prefix validation was initially added when global variable's
section prefix is only added in the codegen pass.

Now the optimizer pass MemProfUse can annotate data section prefix by
making use of data access profiles, so we can remove the validation.
Also calls `setSectionPrefix` which returns whether section prefix is
updated.

This is the 3rd patch as a split of
https://github.com/llvm/llvm-project/pull/155337

Added: 
    

Modified: 
    llvm/lib/CodeGen/StaticDataAnnotator.cpp
    llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/StaticDataAnnotator.cpp b/llvm/lib/CodeGen/StaticDataAnnotator.cpp
index 9b737751c4a98..eac2012017087 100644
--- a/llvm/lib/CodeGen/StaticDataAnnotator.cpp
+++ b/llvm/lib/CodeGen/StaticDataAnnotator.cpp
@@ -78,19 +78,8 @@ bool StaticDataAnnotator::runOnModule(Module &M) {
     if (!llvm::memprof::IsAnnotationOK(GV))
       continue;
 
-    // The implementation below assumes prior passes don't set section prefixes,
-    // and specifically do 'assign' rather than 'update'. So report error if a
-    // section prefix is already set.
-    if (auto maybeSectionPrefix = GV.getSectionPrefix();
-        maybeSectionPrefix && !maybeSectionPrefix->empty())
-      llvm::report_fatal_error("Global variable " + GV.getName() +
-                               " already has a section prefix " +
-                               *maybeSectionPrefix);
-
     StringRef SectionPrefix = SDPI->getConstantSectionPrefix(&GV, PSI);
-    if (SectionPrefix.empty())
-      continue;
-
+    // setSectionPrefix returns true if the section prefix is updated.
     Changed |= GV.setSectionPrefix(SectionPrefix);
   }
 

diff  --git a/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll b/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll
index a0c243be0e7e8..f3950b75a969f 100644
--- a/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll
+++ b/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll
@@ -1,16 +1,15 @@
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-;; A minimal test case. llc will crash if global variables already has a section
-;; prefix. Subsequent PRs will expand on this test case to test the hotness
-;; reconciliation implementation.
-
-; RUN: not llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic \
+;; A minimal test case. Subsequent PRs will expand on this test case
+;; (e.g., with more functions, variables and profiles) and test the hotness
+;; reconcillation implementation.
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic \
 ; RUN:     -partition-static-data-sections=true \
 ; RUN:     -data-sections=true  -unique-section-names=false \
-; RUN:     %s -o - 2>&1 | FileCheck %s --check-prefix=ERR
+; RUN:     %s -o - 2>&1 | FileCheck %s --check-prefix=IR
 
-; ERR: Global variable hot_bss already has a section prefix hot
+; IR: .section .bss.hot.,"aw"
 
 @hot_bss = internal global i32 0, !section_prefix !17