[llvm] 410644f - Clang crash targeting ARM or Thumb when assembling a prel31 relocation variant
Simon Wallis via llvm-commits
llvm-commits at lists.llvm.org
Wed May 13 05:52:53 PDT 2020
Author: Simon Wallis
Date: 2020-05-13T13:52:30+01:00
New Revision: 410644fbf767d5853f170cb2d664a5fef37cb20a
URL: https://github.com/llvm/llvm-project/commit/410644fbf767d5853f170cb2d664a5fef37cb20a
DIFF: https://github.com/llvm/llvm-project/commit/410644fbf767d5853f170cb2d664a5fef37cb20a.diff
LOG: Clang crash targeting ARM or Thumb when assembling a prel31 relocation variant
Summary:
In the assembler or inline assembler,
attempting to use an invalid fixup type
gives a crash with a segmentation fault.
__attribute__((naked))
void foo(void) {
__asm__("mov r9, :lower16:bar(prel31)");
}
This should give a proper error message when building for ARM or Thumb.
This brings it in line with AARCH64.
This fixes all 8 instances of llvm_unreachable("Unsupported Modifier");
in ARM/MCTargetDesc/ARMELFObjectWriter.cpp.
A test is provided for each instance.
Reviewers: llvm-commits, MarkMurrayARM
Reviewed By: MarkMurrayARM
Subscribers: kristof.beyls, hiraditya, danielkiss
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79782
Change-Id: I6971ba37f129cc453568fe71514ccb2ac9d16831
Added:
Modified:
llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
llvm/test/MC/ARM/error-location.s
Removed:
################################################################################
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
index 6bd6addcb6d4..4eaa8102101d 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp
@@ -92,7 +92,9 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case FK_Data_4:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for 4-byte pc-relative data relocation");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None: {
if (const MCSymbolRefExpr *SymRef = Target.getSymA()) {
// For GNU AS compatibility expressions such as
@@ -162,21 +164,27 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case FK_Data_1:
switch (Modifier) {
default:
- llvm_unreachable("unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for 1-byte data relocation");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_ABS8;
}
case FK_Data_2:
switch (Modifier) {
default:
- llvm_unreachable("unsupported modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for 2-byte data relocation");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_ABS16;
}
case FK_Data_4:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for 4-byte data relocation");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_ARM_NONE:
return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_GOT:
@@ -218,7 +226,8 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case ARM::fixup_arm_movt_hi16:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(), "invalid fixup for ARM MOVT instruction");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_MOVT_ABS;
case MCSymbolRefExpr::VK_ARM_SBREL:
@@ -227,7 +236,8 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case ARM::fixup_arm_movw_lo16:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(), "invalid fixup for ARM MOVW instruction");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_MOVW_ABS_NC;
case MCSymbolRefExpr::VK_ARM_SBREL:
@@ -236,7 +246,9 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case ARM::fixup_t2_movt_hi16:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for Thumb MOVT instruction");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_THM_MOVT_ABS;
case MCSymbolRefExpr::VK_ARM_SBREL:
@@ -245,7 +257,9 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target,
case ARM::fixup_t2_movw_lo16:
switch (Modifier) {
default:
- llvm_unreachable("Unsupported Modifier");
+ Ctx.reportError(Fixup.getLoc(),
+ "invalid fixup for Thumb MOVW instruction");
+ return ELF::R_ARM_NONE;
case MCSymbolRefExpr::VK_None:
return ELF::R_ARM_THM_MOVW_ABS_NC;
case MCSymbolRefExpr::VK_ARM_SBREL:
diff --git a/llvm/test/MC/ARM/error-location.s b/llvm/test/MC/ARM/error-location.s
index 29bb5fe1b62c..3f9fa0c23707 100644
--- a/llvm/test/MC/ARM/error-location.s
+++ b/llvm/test/MC/ARM/error-location.s
@@ -1,4 +1,5 @@
@ RUN: not llvm-mc -triple armv7a--none-eabi -filetype obj < %s -o /dev/null 2>&1 | FileCheck %s
+@ RUN: not llvm-mc -triple thumbv7a--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.
@@ -16,7 +17,24 @@
@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: Cannot represent a
diff erence across sections
.word x_a - y_a
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for {{ARM|Thumb}} MOVT instruction
+ movt r9, :upper16: bar(PREL31)
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for {{ARM|Thumb}} MOVW instruction
+ movw r9, :lower16: bar(PREL31)
+
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for 1-byte data relocation
+ .byte f30(PLT)
+
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for 2-byte data relocation
+ .hword f30(PLT)
+
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for 4-byte data relocation
+ .word f30(PLT)
+
+@ CHECK: :[[@LINE+1]]:{{[0-9]+}}: error: invalid fixup for 4-byte pc-relative data relocation
+ .word x_a(PLT) - label1
+label1:
w:
.word 0
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