[llvm] [XCOFF] Ensure .file is emitted before any .info pseudo-ops (PR #71577)

[via llvm-commits]

https://github.com/stephenpeckham created https://github.com/llvm/llvm-project/pull/71577

When generating the assembly code for AIX/XCOFF, the .file pseudo-op needs to be emitted first, before any csects are generated.  Otherwise, information such as the embedded command line will be associated with part of the object file rather than the entire object file.

>From 42c2fbf9af85406c453a3db3ecf328a42605fd76 Mon Sep 17 00:00:00 2001
From: Stephen Peckham <speckham at us.ibm.com>
Date: Tue, 7 Nov 2023 14:17:00 -0500
Subject: [PATCH] [XCOFF] Ensure .file is emitted before any .info pseudo-ops

---
 llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp     | 12 ++++++++++--
 llvm/test/CodeGen/PowerPC/aix-xcoff-data.ll    |  4 ++--
 llvm/test/DebugInfo/XCOFF/empty.ll             |  8 ++++----
 llvm/test/DebugInfo/XCOFF/explicit-section.ll  |  4 ++--
 llvm/test/DebugInfo/XCOFF/function-sections.ll |  4 ++--
 5 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 71bee8cce65126b..8637d0658c2c905 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -443,7 +443,12 @@ bool AsmPrinter::doInitialization(Module &M) {
   const_cast<TargetLoweringObjectFile &>(getObjFileLowering())
       .getModuleMetadata(M);
 
-  OutStreamer->initSections(false, *TM.getMCSubtargetInfo());
+  // On AIX, we delay emitting any section information until
+  // after emitting the .file pseudo-op.  This allows additional
+  // information (such as the embedded command line) to be associated
+  // with all sections in the object file rather than a single section.
+  if (!TM.getTargetTriple().isOSBinFormatXCOFF())
+    OutStreamer->initSections(false, *TM.getMCSubtargetInfo());
 
   // Emit the version-min deployment target directive if needed.
   //
@@ -489,8 +494,11 @@ bool AsmPrinter::doInitialization(Module &M) {
 
   // On AIX, emit bytes for llvm.commandline metadata after .file so that the
   // C_INFO symbol is preserved if any csect is kept by the linker.
-  if (TM.getTargetTriple().isOSBinFormatXCOFF())
+  if (TM.getTargetTriple().isOSBinFormatXCOFF()) {
     emitModuleCommandLines(M);
+    // Now we can generate section information
+    OutStreamer->initSections(false, *TM.getMCSubtargetInfo());
+  }
 
   GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
   assert(MI && "AsmPrinter didn't require GCModuleInfo?");
diff --git a/llvm/test/CodeGen/PowerPC/aix-xcoff-data.ll b/llvm/test/CodeGen/PowerPC/aix-xcoff-data.ll
index 49135499386701d..e84f0b138d25bdd 100644
--- a/llvm/test/CodeGen/PowerPC/aix-xcoff-data.ll
+++ b/llvm/test/CodeGen/PowerPC/aix-xcoff-data.ll
@@ -45,8 +45,8 @@
 
 ; CHECK-NOT: .toc
 
-; CHECK:      .csect [PR],5
-; CHECK-NEXT:  .file
+; CHECK:  .file
+; CHECK-NEXT:      .csect [PR],5
 
 ; CHECK:      .csect .data[RW],5
 ; CHECK-NEXT: .globl  ivar
diff --git a/llvm/test/DebugInfo/XCOFF/empty.ll b/llvm/test/DebugInfo/XCOFF/empty.ll
index 3cb4be26cf04e26..90edc6a6224dd7e 100644
--- a/llvm/test/DebugInfo/XCOFF/empty.ll
+++ b/llvm/test/DebugInfo/XCOFF/empty.ll
@@ -35,8 +35,8 @@ entry:
 !11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !12 = !DILocation(line: 3, column: 3, scope: !8)
 
-; ASM32:               .csect [PR],5
-; ASM32-NEXT:          .file   "1.c"
+; ASM32:          .file   "1.c"
+; ASM32-NEXT:               .csect [PR],5
 ; ASM32-NEXT:          .globl  main[DS]                        # -- Begin function main
 ; ASM32-NEXT:          .globl  .main
 ; ASM32-NEXT:          .align  2
@@ -236,8 +236,8 @@ entry:
 ; ASM32-NEXT:          .byte   1
 ; ASM32-NEXT:  L..debug_line_end0:
 
-; ASM64:               .csect [PR],5
-; ASM64-NEXT:          .file   "1.c"
+; ASM64:          .file   "1.c"
+; ASM64-NEXT:               .csect [PR],5
 ; ASM64-NEXT:          .globl  main[DS]                        # -- Begin function main
 ; ASM64-NEXT:          .globl  .main
 ; ASM64-NEXT:          .align  2
diff --git a/llvm/test/DebugInfo/XCOFF/explicit-section.ll b/llvm/test/DebugInfo/XCOFF/explicit-section.ll
index 5008721795a4100..452c650c6f7f692 100644
--- a/llvm/test/DebugInfo/XCOFF/explicit-section.ll
+++ b/llvm/test/DebugInfo/XCOFF/explicit-section.ll
@@ -42,8 +42,8 @@ entry:
 !15 = !DILocation(line: 3, column: 10, scope: !14)
 !16 = !DILocation(line: 3, column: 3, scope: !14)
 
-; CHECK:               .csect [PR],5
-; CHECK-NEXT:          .file   "2.c"
+; CHECK:          .file   "2.c"
+; CHECK-NEXT:               .csect [PR],5
 ; CHECK-NEXT:          .globl  bar[DS]                         # -- Begin function bar
 ; CHECK-NEXT:          .globl  .bar
 ; CHECK-NEXT:          .align  2
diff --git a/llvm/test/DebugInfo/XCOFF/function-sections.ll b/llvm/test/DebugInfo/XCOFF/function-sections.ll
index 9f4f55623c7de8c..ef3100483e654a9 100644
--- a/llvm/test/DebugInfo/XCOFF/function-sections.ll
+++ b/llvm/test/DebugInfo/XCOFF/function-sections.ll
@@ -37,8 +37,8 @@ entry:
 !13 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 6, type: !9, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
 !14 = !DILocation(line: 8, column: 3, scope: !13)
 
-; CHECK:               .csect [PR],5
-; CHECK-NEXT:          .file   "1.c"
+; CHECK:          .file   "1.c"
+; CHECK-NEXT:               .csect [PR],5
 ; CHECK-NEXT:          .csect .foo[PR],5
 ; CHECK-NEXT:          .globl  foo[DS]                         # -- Begin function foo
 ; CHECK-NEXT:          .globl  .foo[PR]