From 49dba99a89a662da6dc509280ae1082f6e0c6070 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 25 Mar 2015 00:25:37 +0000
Subject: [PATCH] Produce an error instead of asserting on invalid
 .sleb128/.uleb128.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233155 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/MC/MCExpr.h   |  2 +-
 lib/MC/MCAssembler.cpp     | 13 ++++++++++---
 lib/MC/MCExpr.cpp          | 11 ++++-------
 test/MC/X86/invalid-sleb.s |  5 +++++
 4 files changed, 20 insertions(+), 11 deletions(-)
 create mode 100644 test/MC/X86/invalid-sleb.s

diff --git a/include/llvm/MC/MCExpr.h b/include/llvm/MC/MCExpr.h
index 48696750550..1f4edab3b64 100644
--- a/include/llvm/MC/MCExpr.h
+++ b/include/llvm/MC/MCExpr.h
@@ -94,7 +94,7 @@ public:
   bool EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const;
   bool EvaluateAsAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
 
-  int64_t evaluateKnownAbsolute(const MCAsmLayout &Layout) const;
+  bool evaluateKnownAbsolute(int64_t &Res, const MCAsmLayout &Layout) const;
 
   /// EvaluateAsRelocatable - Try to evaluate the expression to a relocatable
   /// value, i.e. an expression of the fixed form (a - b + constant).
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index dada94b9dd3..5243facbe4e 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -1034,7 +1034,10 @@ bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
 
 bool MCAssembler::relaxLEB(MCAsmLayout &Layout, MCLEBFragment &LF) {
   uint64_t OldSize = LF.getContents().size();
-  int64_t Value = LF.getValue().evaluateKnownAbsolute(Layout);
+  int64_t Value;
+  bool Abs = LF.getValue().evaluateKnownAbsolute(Value, Layout);
+  if (!Abs)
+    report_fatal_error("sleb128 and uleb128 expressions must be absolute");
   SmallString<8> &Data = LF.getContents();
   Data.clear();
   raw_svector_ostream OSE(Data);
@@ -1050,7 +1053,9 @@ bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout,
                                      MCDwarfLineAddrFragment &DF) {
   MCContext &Context = Layout.getAssembler().getContext();
   uint64_t OldSize = DF.getContents().size();
-  int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout);
+  int64_t AddrDelta;
+  bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
+  assert(Abs && "We created a line delta with an invalid expression");
   int64_t LineDelta;
   LineDelta = DF.getLineDelta();
   SmallString<8> &Data = DF.getContents();
@@ -1065,7 +1070,9 @@ bool MCAssembler::relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
                                               MCDwarfCallFrameFragment &DF) {
   MCContext &Context = Layout.getAssembler().getContext();
   uint64_t OldSize = DF.getContents().size();
-  int64_t AddrDelta = DF.getAddrDelta().evaluateKnownAbsolute(Layout);
+  int64_t AddrDelta;
+  bool Abs = DF.getAddrDelta().evaluateKnownAbsolute(AddrDelta, Layout);
+  assert(Abs && "We created call frame with an invalid expression");
   SmallString<8> &Data = DF.getContents();
   Data.clear();
   raw_svector_ostream OSE(Data);
diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index abd48c094dd..cac5110a4ff 100644
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -406,13 +406,10 @@ bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler &Asm) const {
   return EvaluateAsAbsolute(Res, &Asm, nullptr, nullptr);
 }
 
-int64_t MCExpr::evaluateKnownAbsolute(const MCAsmLayout &Layout) const {
-  int64_t Res;
-  bool Abs =
-      evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr, true);
-  (void)Abs;
-  assert(Abs && "Not actually absolute");
-  return Res;
+bool MCExpr::evaluateKnownAbsolute(int64_t &Res,
+                                   const MCAsmLayout &Layout) const {
+  return evaluateAsAbsolute(Res, &Layout.getAssembler(), &Layout, nullptr,
+                            true);
 }
 
 bool MCExpr::EvaluateAsAbsolute(int64_t &Res, const MCAssembler *Asm,
diff --git a/test/MC/X86/invalid-sleb.s b/test/MC/X86/invalid-sleb.s
new file mode 100644
index 00000000000..ad27444d608
--- /dev/null
+++ b/test/MC/X86/invalid-sleb.s
@@ -0,0 +1,5 @@
+// RUN: not llvm-mc -filetype=obj -triple x86_64-pc-linux %s -o %t 2>&1 | FileCheck %s
+
+// CHECK:  sleb128 and uleb128 expressions must be absolute
+
+        .sleb128 undefined