[lld] 9ea5b34 - [ELF][RISCV] Use unshifted value for overflow check

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2022-07-13T00:28:29-07:00
New Revision: 9ea5b34f0500f124af552096f586e58dd259424a

URL: https://github.com/llvm/llvm-project/commit/9ea5b34f0500f124af552096f586e58dd259424a
DIFF: https://github.com/llvm/llvm-project/commit/9ea5b34f0500f124af552096f586e58dd259424a.diff

LOG: [ELF][RISCV] Use unshifted value for overflow check

The unshifted value indicates an displacement in bytes which is more meaningful.

Added: 
    

Modified: 
    lld/ELF/Arch/RISCV.cpp
    lld/test/ELF/riscv-branch.s
    lld/test/ELF/riscv-jal.s

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
index ffb68009a1c6..c09bb2e60786 100644
--- a/lld/ELF/Arch/RISCV.cpp
+++ b/lld/ELF/Arch/RISCV.cpp
@@ -300,7 +300,7 @@ void RISCV::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
     return;
 
   case R_RISCV_RVC_BRANCH: {
-    checkInt(loc, static_cast<int64_t>(val) >> 1, 8, rel);
+    checkInt(loc, val, 9, rel);
     checkAlignment(loc, val, 2, rel);
     uint16_t insn = read16le(loc) & 0xE383;
     uint16_t imm8 = extractBits(val, 8, 8) << 12;
@@ -315,7 +315,7 @@ void RISCV::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 
   case R_RISCV_RVC_JUMP: {
-    checkInt(loc, static_cast<int64_t>(val) >> 1, 11, rel);
+    checkInt(loc, val, 12, rel);
     checkAlignment(loc, val, 2, rel);
     uint16_t insn = read16le(loc) & 0xE003;
     uint16_t imm11 = extractBits(val, 11, 11) << 12;
@@ -346,7 +346,7 @@ void RISCV::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 
   case R_RISCV_JAL: {
-    checkInt(loc, static_cast<int64_t>(val) >> 1, 20, rel);
+    checkInt(loc, val, 21, rel);
     checkAlignment(loc, val, 2, rel);
 
     uint32_t insn = read32le(loc) & 0xFFF;
@@ -361,7 +361,7 @@ void RISCV::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 
   case R_RISCV_BRANCH: {
-    checkInt(loc, static_cast<int64_t>(val) >> 1, 12, rel);
+    checkInt(loc, val, 13, rel);
     checkAlignment(loc, val, 2, rel);
 
     uint32_t insn = read32le(loc) & 0x1FFF07F;

diff  --git a/lld/test/ELF/riscv-branch.s b/lld/test/ELF/riscv-branch.s
index 3760e31c6d83..78d1325b1fc3 100644
--- a/lld/test/ELF/riscv-branch.s
+++ b/lld/test/ELF/riscv-branch.s
@@ -23,8 +23,8 @@
 
 # RUN: not ld.lld %t.rv32.o --defsym foo=_start+0x1000 --defsym bar=_start+4-0x1002 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-RANGE %s
 # RUN: not ld.lld %t.rv64.o --defsym foo=_start+0x1000 --defsym bar=_start+4-0x1002 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-RANGE %s
-# ERROR-RANGE: relocation R_RISCV_BRANCH out of range: 2048 is not in [-2048, 2047]; references foo
-# ERROR-RANGE: relocation R_RISCV_BRANCH out of range: -2049 is not in [-2048, 2047]; references bar
+# ERROR-RANGE: relocation R_RISCV_BRANCH out of range: 4096 is not in [-4096, 4095]; references foo
+# ERROR-RANGE: relocation R_RISCV_BRANCH out of range: -4098 is not in [-4096, 4095]; references bar
 
 # RUN: not ld.lld %t.rv32.o --defsym foo=_start+1 --defsym bar=_start-1 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-ALIGN %s
 # RUN: not ld.lld %t.rv64.o --defsym foo=_start+1 --defsym bar=_start-1 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-ALIGN %s

diff  --git a/lld/test/ELF/riscv-jal.s b/lld/test/ELF/riscv-jal.s
index 97a03cc2f9b7..466772ee983f 100644
--- a/lld/test/ELF/riscv-jal.s
+++ b/lld/test/ELF/riscv-jal.s
@@ -23,8 +23,8 @@
 
 # RUN: not ld.lld %t.rv32.o --defsym foo=_start+0x100000 --defsym bar=_start+4-0x100002 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-RANGE %s
 # RUN: not ld.lld %t.rv64.o --defsym foo=_start+0x100000 --defsym bar=_start+4-0x100002 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-RANGE %s
-# ERROR-RANGE: relocation R_RISCV_JAL out of range: 524288 is not in [-524288, 524287]; references foo
-# ERROR-RANGE: relocation R_RISCV_JAL out of range: -524289 is not in [-524288, 524287]; references bar
+# ERROR-RANGE: relocation R_RISCV_JAL out of range: 1048576 is not in [-1048576, 1048575]; references foo
+# ERROR-RANGE: relocation R_RISCV_JAL out of range: -1048578 is not in [-1048576, 1048575]; references bar
 
 # RUN: not ld.lld %t.rv32.o --defsym foo=_start+1 --defsym bar=_start+4+3 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-ALIGN %s
 # RUN: not ld.lld %t.rv64.o --defsym foo=_start+1 --defsym bar=_start+4+3 -o /dev/null 2>&1 | FileCheck --check-prefix=ERROR-ALIGN %s