[llvm] f5e6fba - [AArch64] [Windows] Error out on unsupported symbol locations

[Martin Storsjö via llvm-commits]

Author: Martin Storsjö
Date: 2020-08-06T09:23:46+03:00
New Revision: f5e6fbac24f198d075a7c4bc0879426e79040bcf

URL: https://github.com/llvm/llvm-project/commit/f5e6fbac24f198d075a7c4bc0879426e79040bcf
DIFF: https://github.com/llvm/llvm-project/commit/f5e6fbac24f198d075a7c4bc0879426e79040bcf.diff

LOG: [AArch64] [Windows] Error out on unsupported symbol locations

These might occur in seemingly generic assembly. Previously when
targeting COFF, they were silently ignored, which certainly won't
give the right result. Instead clearly error out, to make it clear
that the assembly needs to be adjusted for this target.

Also change a preexisting report_fatal_error into a proper error
message, pointing out the offending source instruction. This isn't
strictly an internal error, as it can be triggered by user input.

Differential Revision: https://reviews.llvm.org/D85242

Added: 
    llvm/test/MC/AArch64/coff-relocations-diags.s

Modified: 
    llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp
index aa50bd05cb71..aaadc8dc1b60 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp
@@ -11,6 +11,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/COFF.h"
 #include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCFixup.h"
 #include "llvm/MC/MCFixupKindInfo.h"
@@ -48,10 +49,33 @@ unsigned AArch64WinCOFFObjectWriter::getRelocType(
                                       : Target.getSymA()->getKind();
   const MCExpr *Expr = Fixup.getValue();
 
+  if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
+    AArch64MCExpr::VariantKind RefKind = A64E->getKind();
+    switch (AArch64MCExpr::getSymbolLoc(RefKind)) {
+    case AArch64MCExpr::VK_ABS:
+    case AArch64MCExpr::VK_SECREL:
+      // Supported
+      break;
+    default:
+      Ctx.reportError(Fixup.getLoc(), "relocation variant " +
+                                          A64E->getVariantKindName() +
+                                          " unsupported on COFF targets");
+      return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
+    }
+  }
+
   switch (static_cast<unsigned>(Fixup.getKind())) {
   default: {
-    const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
-    report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
+    if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
+      Ctx.reportError(Fixup.getLoc(), "relocation type " +
+                                          A64E->getVariantKindName() +
+                                          " unsupported on COFF targets");
+    } else {
+      const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
+      Ctx.reportError(Fixup.getLoc(), Twine("relocation type ") + Info.Name +
+                                          " unsupported on COFF targets");
+    }
+    return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
   }
 
   case FK_Data_4:

diff  --git a/llvm/test/MC/AArch64/coff-relocations-diags.s b/llvm/test/MC/AArch64/coff-relocations-diags.s
new file mode 100644
index 000000000000..24869ce8349e
--- /dev/null
+++ b/llvm/test/MC/AArch64/coff-relocations-diags.s
@@ -0,0 +1,43 @@
+// RUN: not llvm-mc -triple aarch64-win32 -filetype=obj %s -o /dev/null 2>&1 | FileCheck %s
+
+  adrp x0, :got:symbol
+  // CHECK: error: relocation variant :got: unsupported on COFF targets
+  // CHECK-NEXT: adrp x0, :got:symbol
+  // CHECK-NEXT: ^
+
+  ldr x0, [x0, :got_lo12:symbol]
+  // CHECK: error: relocation variant :got_lo12: unsupported on COFF targets
+  // CHECK-NEXT: ldr x0, [x0, :got_lo12:symbol]
+  // CHECK-NEXT: ^
+
+  adrp x0, :tlsdesc:symbol
+  // CHECK: error: relocation variant :tlsdesc: unsupported on COFF targets
+  // CHECK-NEXT: adrp x0, :tlsdesc:symbol
+  // CHECK-NEXT: ^
+  add x0, x0, :tlsdesc_lo12:symbol
+  // CHECK: error: relocation variant :tlsdesc_lo12: unsupported on COFF targets
+  // CHECK-NEXT: add x0, x0, :tlsdesc_lo12:symbol
+  // CHECK-NEXT: ^
+
+  adrp x0, :gottprel:symbol
+  // CHECK: error: relocation variant :gottprel: unsupported on COFF targets
+  // CHECK-NEXT: adrp x0, :gottprel:symbol
+  // CHECK-NEXT: ^
+  ldr x0, [x0, :gottprel_lo12:symbol]
+  // CHECK: error: relocation variant :gottprel_lo12: unsupported on COFF targets
+  // CHECK-NEXT: ldr x0, [x0, :gottprel_lo12:symbol]
+  // CHECK-NEXT: ^
+
+  add x0, x0, #:dtprel_hi12:symbol, lsl #12
+  // CHECK: error: relocation variant :dtprel_hi12: unsupported on COFF targets
+  // CHECK-NEXT: add x0, x0, #:dtprel_hi12:symbol, lsl #12
+  // CHECK-NEXT: ^
+  add x0, x0, :dtprel_lo12:symbol
+  // CHECK: error: relocation variant :dtprel_lo12: unsupported on COFF targets
+  // CHECK-NEXT: add x0, x0, :dtprel_lo12:symbol
+  // CHECK-NEXT: ^
+
+  movz x0, #:abs_g0:symbol
+  // CHECK: error: relocation type :abs_g0: unsupported on COFF targets
+  // CHECK-NEXT: movz x0, #:abs_g0:symbol
+  // CHECK-NEXT: ^