[PATCH] D73554: [AIX] Don't use a zero fill with a second parameter

[David Tenty via Phabricator via llvm-commits]

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daltenty updated this revision to Diff 240879.
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- Remove include addition


The AIX assembler .space directive can't take a second non-zero argument to fill
with. But LLVM emitFill currently assumes it can. We add a flag to the AsmInfo
to check if non-zero fill is supported, and if we can't zerofill non-zero values
we just splat the .byte directives.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D73554

Files:
  llvm/include/llvm/MC/MCAsmInfo.h
  llvm/lib/MC/MCAsmStreamer.cpp
  llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.cpp
  llvm/test/CodeGen/PowerPC/aix-nonzero-zerofill.ll


Index: llvm/test/CodeGen/PowerPC/aix-nonzero-zerofill.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/PowerPC/aix-nonzero-zerofill.ll
@@ -0,0 +1,6 @@
+; RUN: llc -verify-machineinstrs -O0 -mcpu=pwr4 -mtriple powerpc-ibm-aix-xcoff < %s | FileCheck %s
+; RUN: llc -verify-machineinstrs -O0 -mcpu=pwr4 -mtriple powerpc64-ibm-aix-xcoff < %s | FileCheck %s
+
+ at a = constant [4 x i8] c"\02\02\02\02", align 1
+
+; CHECK-NOT: .space  4,2
Index: llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.cpp
===================================================================
--- llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.cpp
+++ llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCAsmInfo.cpp
@@ -60,5 +60,6 @@
   assert(!IsLittleEndian && "Little-endian XCOFF not supported.");
   CodePointerSize = CalleeSaveStackSlotSize = Is64Bit ? 8 : 4;
   ZeroDirective = "\t.space\t";
+  ZeroDirectiveSupportsNonZeroValue = false;
   SymbolsHaveSMC = true;
 }
Index: llvm/lib/MC/MCAsmStreamer.cpp
===================================================================
--- llvm/lib/MC/MCAsmStreamer.cpp
+++ llvm/lib/MC/MCAsmStreamer.cpp
@@ -1102,12 +1102,24 @@
     return;
 
   if (const char *ZeroDirective = MAI->getZeroDirective()) {
-    // FIXME: Emit location directives
-    OS << ZeroDirective;
-    NumBytes.print(OS, MAI);
-    if (FillValue != 0)
-      OS << ',' << (int)FillValue;
-    EmitEOL();
+    if (MAI->getZeroDirectiveSupportsNonZeroValue() || FillValue == 0) {
+      // FIXME: Emit location directives
+      OS << ZeroDirective;
+      NumBytes.print(OS, MAI);
+      if (FillValue != 0)
+        OS << ',' << (int)FillValue;
+      EmitEOL();
+    } else {
+      assert(isa<MCConstantExpr>(NumBytes) && "Cannot emit non-constant "
+                                               "expression lengths of "
+                                               "fill.");
+      for (int i = 0; i < cast<MCConstantExpr>(NumBytes).getValue(); i++) {
+        OS << "\t.byte\t";
+        NumBytes.print(OS, MAI);
+        OS << (int)FillValue;
+        EmitEOL();
+      }
+    }
     return;
   }
 
Index: llvm/include/llvm/MC/MCAsmInfo.h
===================================================================
--- llvm/include/llvm/MC/MCAsmInfo.h
+++ llvm/include/llvm/MC/MCAsmInfo.h
@@ -177,6 +177,10 @@
   /// used to emit zero bytes.  Defaults to "\t.zero\t"
   const char *ZeroDirective;
 
+  /// This should be set to true if the zero directive supports a value to emit
+  /// other than zero. Defaults to true.
+  bool ZeroDirectiveSupportsNonZeroValue = true;
+
   /// This directive allows emission of an ascii string with the standard C
   /// escape characters embedded into it.  If a target doesn't support this, it
   /// can be set to null. Defaults to "\t.ascii\t"
@@ -543,6 +547,9 @@
   }
 
   const char *getZeroDirective() const { return ZeroDirective; }
+  bool getZeroDirectiveSupportsNonZeroValue() const {
+    return ZeroDirectiveSupportsNonZeroValue;
+  }
   const char *getAsciiDirective() const { return AsciiDirective; }
   const char *getAscizDirective() const { return AscizDirective; }
   bool getAlignmentIsInBytes() const { return AlignmentIsInBytes; }


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