[llvm] r230801 - [PowerPC] Fix PR22711 - Misaligned .toc section

[Bill Schmidt]

Author: wschmidt
Date: Fri Feb 27 16:14:10 2015
New Revision: 230801

URL: http://llvm.org/viewvc/llvm-project?rev=230801&view=rev
Log:
[PowerPC] Fix PR22711 - Misaligned .toc section

Straightforward patch to emit an alignment directive when emitting a
TOC entry.  The test case was generated from the test in PR22711 that
demonstrated a misaligned .toc section.  The object code is run
through llvm-readobj to verify that the correct alignment has been
applied to the .toc section.

Thanks to Ulrich Weigand for running down where the fix was needed.

Added:
    llvm/trunk/test/CodeGen/PowerPC/pr22711.ll
Modified:
    llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp

Modified: llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp?rev=230801&r1=230800&r2=230801&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.cpp Fri Feb 27 16:14:10 2015
@@ -145,6 +145,7 @@ public:
   }
   void emitTCEntry(const MCSymbol &S) override {
     // Creates a R_PPC64_TOC relocation
+    Streamer.EmitValueToAlignment(8);
     Streamer.EmitSymbolValue(&S, 8);
   }
   void emitMachine(StringRef CPU) override {

Added: llvm/trunk/test/CodeGen/PowerPC/pr22711.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/pr22711.ll?rev=230801&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/pr22711.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/pr22711.ll Fri Feb 27 16:14:10 2015
@@ -0,0 +1,65 @@
+; Verify that the .toc section is aligned on an 8-byte boundary.
+
+; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr8 -filetype=obj -o - | llvm-readobj --sections | FileCheck %s
+
+define void @test(i32* %a) {
+entry:
+  %a.addr = alloca i32*, align 8
+  store i32* %a, i32** %a.addr, align 8
+  %0 = load i32** %a.addr, align 8
+  %incdec.ptr = getelementptr inbounds i32* %0, i32 1
+  store i32* %incdec.ptr, i32** %a.addr, align 8
+  %1 = load i32* %0, align 4
+  switch i32 %1, label %sw.epilog [
+    i32 17, label %sw.bb
+    i32 13, label %sw.bb1
+    i32 11, label %sw.bb2
+    i32 7, label %sw.bb3
+    i32 5, label %sw.bb4
+    i32 3, label %sw.bb5
+    i32 2, label %sw.bb6
+  ]
+
+sw.bb:                                            ; preds = %entry
+  %2 = load i32** %a.addr, align 8
+  store i32 2, i32* %2, align 4
+  br label %sw.epilog
+
+sw.bb1:                                           ; preds = %entry
+  %3 = load i32** %a.addr, align 8
+  store i32 3, i32* %3, align 4
+  br label %sw.epilog
+
+sw.bb2:                                           ; preds = %entry
+  %4 = load i32** %a.addr, align 8
+  store i32 5, i32* %4, align 4
+  br label %sw.epilog
+
+sw.bb3:                                           ; preds = %entry
+  %5 = load i32** %a.addr, align 8
+  store i32 7, i32* %5, align 4
+  br label %sw.epilog
+
+sw.bb4:                                           ; preds = %entry
+  %6 = load i32** %a.addr, align 8
+  store i32 11, i32* %6, align 4
+  br label %sw.epilog
+
+sw.bb5:                                           ; preds = %entry
+  %7 = load i32** %a.addr, align 8
+  store i32 13, i32* %7, align 4
+  br label %sw.epilog
+
+sw.bb6:                                           ; preds = %entry
+  %8 = load i32** %a.addr, align 8
+  store i32 17, i32* %8, align 4
+  br label %sw.epilog
+
+sw.epilog:                                        ; preds = %entry, %sw.bb6, %sw.bb5, %sw.bb4, %sw.bb3, %sw.bb2, %sw.bb1, %sw.bb
+  ret void
+}
+
+; CHECK: Name: .toc
+; CHECK: AddressAlignment: 8
+; CHECK: Name: .rela.toc
+