[Assembler] Better error messages for .org directive

Currently, the error messages we emit for the .org directive when the
expression is not absolute or is out of range do not include the line
number of the directive, so it can be hard to track down the problem if
a file contains many .org directives.

This patch stores the source location in the MCOrgFragment, so that it
can be used for diagnostics emitted during layout.

Since layout is an iterative process, and the errors are detected during
each iteration, it would have been possible for errors to be reported
multiple times. To prevent this, I've made the assembler bail out after
each iteration if any errors have been reported. This will still allow
multiple unrelated errors to be reported in the common case where they
are all detected in the first round of layout.

Differential Revision: https://reviews.llvm.org/D27411

llvm-svn: 289643

diff --git a/llvm/include/llvm/MC/MCFragment.h b/llvm/include/llvm/MC/MCFragment.h
index 02b7325..edb740f 100644 (file)
--- a/llvm/include/llvm/MC/MCFragment.h
+++ b/llvm/include/llvm/MC/MCFragment.h
@@ -346,9 +346,13 @@ class MCOrgFragment : public MCFragment {
   /// Value - Value to use for filling bytes.
   int8_t Value;
 
+  /// Loc - Source location of the directive that this fragment was created for.
+  SMLoc Loc;
+
 public:
-  MCOrgFragment(const MCExpr &Offset, int8_t Value, MCSection *Sec = nullptr)
-      : MCFragment(FT_Org, false, 0, Sec), Offset(&Offset), Value(Value) {}
+  MCOrgFragment(const MCExpr &Offset, int8_t Value, SMLoc Loc,
+                MCSection *Sec = nullptr)
+      : MCFragment(FT_Org, false, 0, Sec), Offset(&Offset), Value(Value), Loc(Loc) {}
 
   /// \name Accessors
   /// @{
@@ -357,6 +361,8 @@ public:
 
   uint8_t getValue() const { return Value; }
 
+  SMLoc getLoc() const { return Loc; }
+
   /// @}
 
   static bool classof(const MCFragment *F) {

diff --git a/llvm/include/llvm/MC/MCObjectStreamer.h b/llvm/include/llvm/MC/MCObjectStreamer.h
index 0d53899..f9111b7 100644 (file)
--- a/llvm/include/llvm/MC/MCObjectStreamer.h
+++ b/llvm/include/llvm/MC/MCObjectStreamer.h
@@ -112,7 +112,8 @@ public:
                             unsigned MaxBytesToEmit = 0) override;
   void EmitCodeAlignment(unsigned ByteAlignment,
                          unsigned MaxBytesToEmit = 0) override;
-  void emitValueToOffset(const MCExpr *Offset, unsigned char Value) override;
+  void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
+                         SMLoc Loc) override;
   void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
                              unsigned Column, unsigned Flags,
                              unsigned Isa, unsigned Discriminator,

diff --git a/llvm/include/llvm/MC/MCStreamer.h b/llvm/include/llvm/MC/MCStreamer.h
index cc2e30e..7b4bf29 100644 (file)
--- a/llvm/include/llvm/MC/MCStreamer.h
+++ b/llvm/include/llvm/MC/MCStreamer.h
@@ -684,7 +684,8 @@ public:
   /// \param Offset - The offset to reach. This may be an expression, but the
   /// expression must be associated with the current section.
   /// \param Value - The value to use when filling bytes.
-  virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value = 0);
+  virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
+                                 SMLoc Loc);
 
   /// @}
 

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index e36903e..352219e 100644 (file)
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -209,7 +209,8 @@ public:
                          unsigned MaxBytesToEmit = 0) override;
 
   void emitValueToOffset(const MCExpr *Offset,
-                         unsigned char Value = 0) override;
+                         unsigned char Value,
+                         SMLoc Loc) override;
 
   void EmitFileDirective(StringRef Filename) override;
   unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
@@ -1011,7 +1012,8 @@ void MCAsmStreamer::EmitCodeAlignment(unsigned ByteAlignment,
 }
 
 void MCAsmStreamer::emitValueToOffset(const MCExpr *Offset,
-                                      unsigned char Value) {
+                                      unsigned char Value,
+                                      SMLoc Loc) {
   // FIXME: Verify that Offset is associated with the current section.
   OS << ".org ";
   Offset->print(OS, MAI);

diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 4735f6c..83fcec9 100644 (file)
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -278,22 +278,29 @@ uint64_t MCAssembler::computeFragmentSize(const MCAsmLayout &Layout,
   case MCFragment::FT_Org: {
     const MCOrgFragment &OF = cast<MCOrgFragment>(F);
     MCValue Value;
-    if (!OF.getOffset().evaluateAsValue(Value, Layout))
-      report_fatal_error("expected assembly-time absolute expression");
+    if (!OF.getOffset().evaluateAsValue(Value, Layout)) {
+      getContext().reportError(OF.getLoc(),
+                               "expected assembly-time absolute expression");
+        return 0;
+    }
 
-    // FIXME: We need a way to communicate this error.
     uint64_t FragmentOffset = Layout.getFragmentOffset(&OF);
     int64_t TargetLocation = Value.getConstant();
     if (const MCSymbolRefExpr *A = Value.getSymA()) {
       uint64_t Val;
-      if (!Layout.getSymbolOffset(A->getSymbol(), Val))
-        report_fatal_error("expected absolute expression");
+      if (!Layout.getSymbolOffset(A->getSymbol(), Val)) {
+        getContext().reportError(OF.getLoc(), "expected absolute expression");
+        return 0;
+      }
       TargetLocation += Val;
     }
     int64_t Size = TargetLocation - FragmentOffset;
-    if (Size < 0 || Size >= 0x40000000)
-      report_fatal_error("invalid .org offset '" + Twine(TargetLocation) +
-                         "' (at offset '" + Twine(FragmentOffset) + "')");
+    if (Size < 0 || Size >= 0x40000000) {
+      getContext().reportError(
+          OF.getLoc(), "invalid .org offset '" + Twine(TargetLocation) +
+                           "' (at offset '" + Twine(FragmentOffset) + "')");
+      return 0;
+    }
     return Size;
   }
 
@@ -660,7 +667,8 @@ void MCAssembler::layout(MCAsmLayout &Layout) {
 
   // Layout until everything fits.
   while (layoutOnce(Layout))
-    continue;
+    if (getContext().hadError())
+      return;
 
   DEBUG_WITH_TYPE("mc-dump", {
       llvm::errs() << "assembler backend - post-relaxation\n--\n";
@@ -912,7 +920,9 @@ bool MCAssembler::layoutOnce(MCAsmLayout &Layout) {
 void MCAssembler::finishLayout(MCAsmLayout &Layout) {
   // The layout is done. Mark every fragment as valid.
   for (unsigned int i = 0, n = Layout.getSectionOrder().size(); i != n; ++i) {
-    Layout.getFragmentOffset(&*Layout.getSectionOrder()[i]->rbegin());
+    MCSection &Section = *Layout.getSectionOrder()[i];
+    Layout.getFragmentOffset(&*Section.rbegin());
+    computeFragmentSize(Layout, *Section.rbegin());
   }
   getBackend().finishLayout(*this, Layout);
 }

diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 123295d..cae5c1f 100644 (file)
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -440,8 +440,9 @@ void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
 }
 
 void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,
-                                         unsigned char Value) {
-  insert(new MCOrgFragment(*Offset, Value));
+                                         unsigned char Value,
+                                         SMLoc Loc) {
+  insert(new MCOrgFragment(*Offset, Value, Loc));
 }
 
 // Associate DTPRel32 fixup with data and resize data area

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 7ebe7b5..90a210f 100644 (file)
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -2965,6 +2965,7 @@ bool AsmParser::parseDirectiveFill() {
 ///  ::= .org expression [ , expression ]
 bool AsmParser::parseDirectiveOrg() {
   const MCExpr *Offset;
+  SMLoc OffsetLoc = Lexer.getLoc();
   if (checkForValidSection() || parseExpression(Offset))
     return true;
 
@@ -2976,7 +2977,7 @@ bool AsmParser::parseDirectiveOrg() {
   if (parseToken(AsmToken::EndOfStatement))
     return addErrorSuffix(" in '.org' directive");
 
-  getStreamer().emitValueToOffset(Offset, FillExpr);
+  getStreamer().emitValueToOffset(Offset, FillExpr, OffsetLoc);
   return false;
 }
 
@@ -5502,7 +5503,7 @@ bool parseAssignmentExpression(StringRef Name, bool allow_redef,
                           "invalid reassignment of non-absolute variable '" +
                               Name + "'");
   } else if (Name == ".") {
-    Parser.getStreamer().emitValueToOffset(Value, 0);
+    Parser.getStreamer().emitValueToOffset(Value, 0, EqualLoc);
     return false;
   } else
     Sym = Parser.getContext().getOrCreateSymbol(Name);

diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index ebbf811..5cfa3ae 100644 (file)
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -820,7 +820,8 @@ void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
                                       unsigned MaxBytesToEmit) {}
 void MCStreamer::EmitCodeAlignment(unsigned ByteAlignment,
                                    unsigned MaxBytesToEmit) {}
-void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value) {}
+void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value,
+                                   SMLoc Loc) {}
 void MCStreamer::EmitBundleAlignMode(unsigned AlignPow2) {}
 void MCStreamer::EmitBundleLock(bool AlignToEnd) {}
 void MCStreamer::FinishImpl() {}

diff --git a/llvm/test/MC/AArch64/error-location-during-layout.s b/llvm/test/MC/AArch64/error-location-during-layout.s
new file mode 100644 (file)
index 0000000..4af1568
--- /dev/null
+++ b/llvm/test/MC/AArch64/error-location-during-layout.s
@@ -0,0 +1,14 @@
+// RUN: not llvm-mc -triple aarch64--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+  .section a
+  .space 8
+// CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid .org offset '4' (at offset '8')
+  .org 4
+
+  .section b
+// CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: expected absolute expression
+  .org undef
+
+  .section c
+// CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: expected assembly-time absolute expression
+  .org -undef

diff --git a/llvm/test/MC/AArch64/error-location-post-layout.s b/llvm/test/MC/AArch64/error-location-post-layout.s
new file mode 100644 (file)
index 0000000..8b41c67
--- /dev/null
+++ b/llvm/test/MC/AArch64/error-location-post-layout.s
@@ -0,0 +1,14 @@
+// RUN: not llvm-mc -triple aarch64--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+// Note: These errors are not always emitted in the order in which the relevant
+// source appears, this file is carefully ordered so that that is the case.
+
+// CHECK: <unknown>:0: error: expression could not be evaluated
+  .set v1, -undef
+
+  .comm common, 4
+// CHECK: <unknown>:0: error: Common symbol 'common' cannot be used in assignment expr
+  .set v3, common
+
+// CHECK: <unknown>:0: error: symbol 'undef' could not be evaluated in a subtraction expression
+  .set v2, a-undef

diff --git a/llvm/test/MC/AArch64/error-location.s b/llvm/test/MC/AArch64/error-location.s
index 6bb75f8..a4f083b 100644 (file)
--- a/llvm/test/MC/AArch64/error-location.s
+++ b/llvm/test/MC/AArch64/error-location.s
@@ -34,16 +34,6 @@
 // CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for 32-bit load/store instruction
   ldr w0, [x1, :gottprel_lo12:undef]
 
-// CHECK: <unknown>:0: error: expression could not be evaluated
-  .set v1, -undef
-
-  .comm common, 4
-// CHECK: <unknown>:0: error: Common symbol 'common' cannot be used in assignment expr
-  .set v3, common
-
-// CHECK: <unknown>:0: error: symbol 'undef' could not be evaluated in a subtraction expression
-  .set v2, a-undef
-
 
 
 w:

diff --git a/llvm/test/MC/ARM/error-location-post-layout.s b/llvm/test/MC/ARM/error-location-post-layout.s
new file mode 100644 (file)
index 0000000..d6a59fd
--- /dev/null
+++ b/llvm/test/MC/ARM/error-location-post-layout.s
@@ -0,0 +1,14 @@
+@ RUN: not llvm-mc -triple armv7a--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+
+@ Note: These errors are not always emitted in the order in which the relevant
+@ source appears, this file is carefully ordered so that that is the case.
+
+@ CHECK: <unknown>:0: error: expression could not be evaluated
+  .set v1, -undef
+
+  .comm common, 4
+@ CHECK: <unknown>:0: error: Common symbol 'common' cannot be used in assignment expr
+  .set v3, common
+
+@ CHECK: <unknown>:0: error: symbol 'undef' could not be evaluated in a subtraction expression
+  .set v2, a-undef

diff --git a/llvm/test/MC/ARM/error-location.s b/llvm/test/MC/ARM/error-location.s
index 58ec585..652de29 100644 (file)
--- a/llvm/test/MC/ARM/error-location.s
+++ b/llvm/test/MC/ARM/error-location.s
@@ -16,16 +16,6 @@
 @ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: Cannot represent a difference across sections
   .word x_a - y_a
 
-@ CHECK: <unknown>:0: error: expression could not be evaluated
-  .set v1, -undef
-
-  .comm common, 4
-@ CHECK: <unknown>:0: error: Common symbol 'common' cannot be used in assignment expr
-  .set v3, common
-
-@ CHECK: <unknown>:0: error: symbol 'undef' could not be evaluated in a subtraction expression
-  .set v2, a-undef
-
 
 
 w:

diff --git a/llvm/test/MC/AsmParser/dot-symbol-assignment-backwards.s b/llvm/test/MC/AsmParser/dot-symbol-assignment-backwards.s
index 2619788..f104864 100644 (file)
--- a/llvm/test/MC/AsmParser/dot-symbol-assignment-backwards.s
+++ b/llvm/test/MC/AsmParser/dot-symbol-assignment-backwards.s
@@ -7,6 +7,6 @@
 . = . + 10
        .byte 2
 
-# CHECK: LLVM ERROR: invalid .org offset '24' (at offset '28')
+# CHECK: error: invalid .org offset '24' (at offset '28')
 . = 0x18
        .byte 3