This revision was automatically updated to reflect the committed changes.
Closed by commit rG14135f50a036: [lldb/Value] Avoid reading more data than the
host has available (authored by vsk).
Herald added a project: LLDB.
Changed prior to commit:
https://reviews.llvm.org/D73148?vs=241814&id=241846#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D73148/new/
https://reviews.llvm.org/D73148
Files:
lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/Makefile
lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/TestNoASanExceptionAfterEvalOP_piece.py
lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/main.cpp
lldb/source/Core/ValueObjectVariable.cpp
lldb/test/Shell/SymbolFile/DWARF/DW_OP_piece-smaller-than-struct.s
Index: lldb/test/Shell/SymbolFile/DWARF/DW_OP_piece-smaller-than-struct.s
===================================================================
--- /dev/null
+++ lldb/test/Shell/SymbolFile/DWARF/DW_OP_piece-smaller-than-struct.s
@@ -0,0 +1,110 @@
+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-pc-linux %s
+# RUN: %lldb %t -o "target variable reset" -b | FileCheck %s
+
+# CHECK: (lldb) target variable reset
+# CHECK: (auto_reset) reset = {
+# CHECK: ptr = 0xdeadbeefbaadf00d
+# Note: We need to find some way to represent "prev" as unknown/undefined.
+# CHECK: prev = false
+# CHECK: }
+
+ .section .debug_abbrev,"",@progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 36 # DW_TAG_base_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 62 # DW_AT_encoding
+ .byte 11 # DW_FORM_data1
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # Abbreviation Code
+ .byte 19 # DW_TAG_structure_type
+ .byte 1 # DW_CHILDREN_yes
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 5 # Abbreviation Code
+ .byte 13 # DW_TAG_member
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 56 # DW_AT_data_member_location
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 6 # Abbreviation Code
+ .byte 15 # DW_TAG_pointer_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+
+ .section .debug_info,"",@progbits
+.Lcu_begin0:
+ .long .Lcu_end-.Lcu_start # Length of Unit
+.Lcu_start:
+ .short 4 # DWARF version number
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x6c DW_TAG_compile_unit
+.Lbool:
+ .byte 3 # Abbrev [3] 0x33:0x7 DW_TAG_base_type
+ .asciz "bool" # DW_AT_name
+ .byte 2 # DW_AT_encoding
+ .byte 1 # DW_AT_byte_size
+ .byte 2 # Abbrev [2] 0x3a:0x15 DW_TAG_variable
+ .asciz "reset" # DW_AT_name
+ .long .Lstruct # DW_AT_type
+ .byte 2f-1f # DW_AT_location
+1:
+ .byte 0xe # DW_OP_constu
+ .quad 0xdeadbeefbaadf00d
+ .byte 0x9f # DW_OP_stack_value
+ .byte 0x93 # DW_OP_piece
+ .uleb128 8
+ # Note: Only the first 8 bytes of the struct are described.
+2:
+.Lstruct:
+ .byte 4 # Abbrev [4] 0x4f:0x22 DW_TAG_structure_type
+ .asciz "auto_reset" # DW_AT_name
+ .byte 16 # DW_AT_byte_size
+ .byte 5 # Abbrev [5] 0x58:0xc DW_TAG_member
+ .asciz "ptr" # DW_AT_name
+ .long .Lbool_ptr # DW_AT_type
+ .byte 0 # DW_AT_data_member_location
+ .byte 5 # Abbrev [5] 0x64:0xc DW_TAG_member
+ .asciz "prev" # DW_AT_name
+ .long .Lbool # DW_AT_type
+ .byte 8 # DW_AT_data_member_location
+ .byte 0 # End Of Children Mark
+.Lbool_ptr:
+ .byte 6 # Abbrev [6] 0x71:0x5 DW_TAG_pointer_type
+ .long .Lbool # DW_AT_type
+ .byte 0 # End Of Children Mark
+.Lcu_end:
Index: lldb/source/Core/ValueObjectVariable.cpp
===================================================================
--- lldb/source/Core/ValueObjectVariable.cpp
+++ lldb/source/Core/ValueObjectVariable.cpp
@@ -166,6 +166,27 @@
Value::ValueType value_type = m_value.GetValueType();
+ // The size of the buffer within m_value can be less than the size
+ // prescribed by its type. E.g. this can happen when an expression only
+ // partially describes an object (say, because it contains DW_OP_piece).
+ //
+ // In this case, grow m_value to the expected size. An alternative way to
+ // handle this is to teach Value::GetValueAsData() and ValueObjectChild
+ // not to read past the end of a host buffer, but this gets impractically
+ // complicated as a Value's host buffer may be shared with a distant
+ // ancestor or sibling in the ValueObject hierarchy.
+ //
+ // FIXME: When we grow m_value, we should represent the added bits as
+ // undefined somehow instead of as 0's.
+ if (value_type == Value::eValueTypeHostAddress &&
+ compiler_type.IsValid()) {
+ if (size_t value_buf_size = m_value.GetBuffer().GetByteSize()) {
+ size_t value_size = m_value.GetValueByteSize(&m_error, &exe_ctx);
+ if (m_error.Success() && value_buf_size < value_size)
+ m_value.ResizeData(value_size);
+ }
+ }
+
Process *process = exe_ctx.GetProcessPtr();
const bool process_is_alive = process && process->IsAlive();
Index: lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/main.cpp
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/main.cpp
@@ -0,0 +1,31 @@
+// This is a regression test that checks whether lldb can inspect the variables
+// in this program without triggering an ASan exception.
+
+__attribute__((noinline, optnone)) int use(int x) { return x; }
+
+volatile int sink;
+
+struct S1 {
+ int f1;
+ int *f2;
+};
+
+struct S2 {
+ char a, b;
+ int pad;
+ S2(int x) {
+ a = x & 0xff;
+ b = x & 0xff00;
+ }
+};
+
+int main() {
+ S1 v1;
+ v1.f1 = sink;
+ v1.f2 = nullptr;
+ sink++; //% self.expect("frame variable v1", substrs=["S1"])
+ S2 v2(v1.f1);
+ sink += use(v2.a); //% self.expect("frame variable v2", substrs=["S2"])
+ sink += use(v2.pad); //% self.expect("frame variable v2", substrs=["S2"])
+ return 0;
+}
Index: lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/TestNoASanExceptionAfterEvalOP_piece.py
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/TestNoASanExceptionAfterEvalOP_piece.py
@@ -0,0 +1,4 @@
+from lldbsuite.test import lldbinline
+from lldbsuite.test import decorators
+
+lldbinline.MakeInlineTest(__file__, globals())
Index: lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/Makefile
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/optimized_code/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+CXXFLAGS_EXTRAS := -O2
+include Makefile.rules
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