From 97785af4644957a90e7ce238a7983d2cffd73d25 Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Fri, 2 Mar 2018 08:11:58 +0000
Subject: [PATCH] [ELF] - Report error when memory region is overflowed by data
 commands.

LLD can not catch a memory area overflow when using a data command.
If we have the script below:

.foo :
{
  *(.foo)
  BYTE(0x1)
} > ram

where BYTE overflows the ram region, we do not report it currently.
Patch fixes that.

Differential revision: https://reviews.llvm.org/D43948

llvm-svn: 326545
---
 lld/ELF/LinkerScript.cpp                      | 27 ++++++++++---------
 .../linkerscript/memory-data-commands.test    | 22 +++++++++++++++
 2 files changed, 37 insertions(+), 12 deletions(-)
 create mode 100644 lld/test/ELF/linkerscript/memory-data-commands.test

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index f1a6d6381f16..f99d55d3541f 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -621,6 +621,16 @@ uint64_t LinkerScript::advance(uint64_t Size, unsigned Alignment) {
   return End;
 }
 
+// Expands the memory region by the specified size.
+static void expandMemoryRegion(MemoryRegion *MemRegion, uint64_t Size,
+                               StringRef RegionName, StringRef SecName) {
+  MemRegion->CurPos += Size;
+  uint64_t NewSize = MemRegion->CurPos - MemRegion->Origin;
+  if (NewSize > MemRegion->Length)
+    error("section '" + SecName + "' will not fit in region '" + RegionName +
+          "': overflowed by " + Twine(NewSize - MemRegion->Length) + " bytes");
+}
+
 void LinkerScript::output(InputSection *S) {
   uint64_t Before = advance(0, 1);
   uint64_t Pos = advance(S->getSize(), S->Alignment);
@@ -637,17 +647,9 @@ void LinkerScript::output(InputSection *S) {
     Ctx->LMARegion->CurPos += Pos - Before;
   // FIXME: should we also produce overflow errors for LMARegion?
 
-  if (Ctx->MemRegion) {
-    uint64_t &CurOffset = Ctx->MemRegion->CurPos;
-    CurOffset += Pos - Before;
-    uint64_t CurSize = CurOffset - Ctx->MemRegion->Origin;
-    if (CurSize > Ctx->MemRegion->Length) {
-      uint64_t OverflowAmt = CurSize - Ctx->MemRegion->Length;
-      error("section '" + Ctx->OutSec->Name + "' will not fit in region '" +
-            Ctx->MemRegion->Name + "': overflowed by " + Twine(OverflowAmt) +
-            " bytes");
-    }
-  }
+  if (Ctx->MemRegion)
+    expandMemoryRegion(Ctx->MemRegion, Pos - Before, Ctx->MemRegion->Name,
+                       Ctx->OutSec->Name);
 }
 
 void LinkerScript::switchTo(OutputSection *Sec) {
@@ -738,7 +740,8 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
       Cmd->Offset = Dot - Ctx->OutSec->Addr;
       Dot += Cmd->Size;
       if (Ctx->MemRegion)
-        Ctx->MemRegion->CurPos += Cmd->Size;
+        expandMemoryRegion(Ctx->MemRegion, Cmd->Size, Ctx->MemRegion->Name,
+                           Ctx->OutSec->Name);
       if (Ctx->LMARegion)
         Ctx->LMARegion->CurPos += Cmd->Size;
       Ctx->OutSec->Size = Dot - Ctx->OutSec->Addr;
diff --git a/lld/test/ELF/linkerscript/memory-data-commands.test b/lld/test/ELF/linkerscript/memory-data-commands.test
new file mode 100644
index 000000000000..2762ec9e985f
--- /dev/null
+++ b/lld/test/ELF/linkerscript/memory-data-commands.test
@@ -0,0 +1,22 @@
+# REQUIRES: x86
+
+# RUN: echo ".section .foo,\"a\"" > %t.s
+# RUN: echo ".quad 1" >> %t.s
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %t.s -o %t.o
+
+# RUN: not ld.lld -o %t %t.o --script %s 2>&1 | FileCheck %s
+
+# Check we are able to catch 'ram' overflow caused by BYTE command.
+# CHECK: error: section '.foo' will not fit in region 'ram': overflowed by 1 bytes
+
+MEMORY {
+  text (rwx): org = 0x0, len = 0x1000
+  ram (rwx): org = 0x1000, len = 8
+}
+SECTIONS {
+  .text : { *(.text) } > text
+  .foo : {
+    *(.foo)
+    BYTE(0x1)
+  } > ram
+}