[PATCH] D105271: [PowerPC][ELF]make sure local variable space does not overlap with parameter save area

[ChenZheng via Phabricator via llvm-commits]

shchenz created this revision.
shchenz added reviewers: jsji, uweigand, sfertile, nemanjai, PowerPC.
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This is a bug fix for byval parameter passing in the caller site.

Currently in the caller site, `byval` parameter which size is not smaller than 8 will be stored into parameter save area.

See:

  LowerCall_64SVR4  -> createMemcpyOutsideCallSeq()

But in the previous `HasParameterArea` checking, it is not set to true. So this will cause the stack memory for local variable space and parameter save area overlap.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105271

Files:
  llvm/lib/Target/PowerPC/PPCISelLowering.cpp
  llvm/test/CodeGen/PowerPC/byval.ll


Index: llvm/test/CodeGen/PowerPC/byval.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/byval.ll
+++ llvm/test/CodeGen/PowerPC/byval.ll
@@ -9,15 +9,15 @@
 declare dso_local i32 @foo1(%struct* byval(%struct) %var)
 declare dso_local void @foo(%struct* %var)
 
-; FIXME: for the byval parameter %x, now the memory for local variable and
-; for parameter save area are overlap.
+; for the byval parameter %x, make sure the memory for local variable and
+; for parameter save area are not overlap.
 ; For the below case,
-; the local variable space is r1 + 40 ~ r1 + 76
+; the local variable space is r1 + 104 ~ r1 + 140
 ; the parameter save area is r1 + 32 ~ r1 + 68
 
 define dso_local i32 @bar() {
 ; CHECK-LABEL: bar:
-; CHECK:    addi 30, 1, 40
+; CHECK:    addi 30, 1, 104
 ; CHECK:    li 3, 16
 ; CHECK:    lxvd2x 0, 30, 3
 ; CHECK:    li 3, 48
@@ -25,7 +25,7 @@
 ; CHECK:    li 3, 32
 ; CHECK:    lxvd2x 0, 0, 30
 ; CHECK:    stxvd2x 0, 1, 3
-; CHECK:    lwz 3, 72(1)
+; CHECK:    lwz 3, 136(1)
 ; CHECK:    stw 3, 64(1)
 entry:
   %x = alloca %struct, align 4
Index: llvm/lib/Target/PowerPC/PPCISelLowering.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -6015,7 +6015,8 @@
         }
         HasParameterArea = true;
       }
-    }
+    } else if (Flags.isByVal() && Flags.getByValSize() >= 8)
+      HasParameterArea = true;
 
     /* Respect alignment of argument on the stack.  */
     auto Alignement =


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