bcm5719-llvm/lldb/source/Expression, branch meklort-10.0.1

Fix a buffer-size bug when the first DW_OP_piece is undefined

2020-02-19T13:20:34+00:00

and document the shortcomings of LLDB's partially defined DW_OP_piece handling. This would manifest as "DW_OP_piece for offset foo but top of stack is of size bar". rdar://problem/46262998 Differential Revision: https://reviews.llvm.org/D72880 (cherry picked from commit f55ab6f90b7317a6bb85303a6102702bdae1199e)

Add testing for DW_OP_piece and fix a bug with small Scalar values.

2020-02-19T13:20:33+00:00

By switching to Scalars that are backed by explicitly-sized APInts we can avoid a bug that increases the buffer reserved for a small piece to the next-largest host integer type. This manifests as "DW_OP_piece for offset foo but top of stack is of size bar". Differential Revision: https://reviews.llvm.org/D72879 (cherry picked from commit 7b0d58e339b271e3b1d9dc14b781b57fa0262e3a)

[lldb] Don't defend against internal LLVM errors in IRInterpreter

2020-01-14T08:55:34+00:00

Summary: Whenever we cast an LLVM instruction to one of its subclasses, we do a double check if the RTTI enum value actually allows us to cast the class. I don't see a way this can ever happen as even when LLVM's RTTI system has some corrupt internal state (which we probably should not test in the first place) we just reuse LLVM RTTI to do the second check. This also means that if we ever make an actual programming error in this function (e.g., have a enum value and then cast it to a different subclass), we just silently fall back to the JIT in our tests. We also can't test this code in any reasonable way. This removes the checks and uses `llvm::cast` instead which will raise a fatal error when casting fails. Reviewers: labath, mib Reviewed By: labath Subscribers: abidh, JDevlieghere, lldb-commits Tags: #lldb Differential Revision: https://reviews.llvm.org/D72596

[lldb][NFC] Use range-based for loops in IRInterpreter

2020-01-13T10:58:45+00:00

Add missing nullptr checks.

2020-01-10T16:52:46+00:00

GetPersistentExpressionStateForLanguage() can return a nullptr if it cannot construct a typesystem. This patch adds missing nullptr checks at all uses. Inspired by rdar://problem/58317195 Differential Revision: https://reviews.llvm.org/D72413

[lldb/DWARF] Fix mixed v4+v5 location lists

2020-01-09T12:19:29+00:00

Summary: Our code was expecting that a single (symbol) file contains only one kind of location lists. This is not correct (on non-apple platforms, at least) as a file can compile units with different dwarf versions. This patch moves the deteremination of location list flavour down to the compile unit level, fixing this problem. I have also tried to rougly align the code with the llvm DWARFUnit. Fully matching the API is not possible because of how lldb's DWARFExpression lives separately from the rest of the DWARF code, but this is at least a step in the right direction. Reviewers: JDevlieghere, aprantl, clayborg Subscribers: dblaikie, lldb-commits Tags: #lldb Differential Revision: https://reviews.llvm.org/D71751

[UserExpression] Clean up `return` after `else`.

2020-01-04T00:52:10+00:00

[lldb] Fix ARM32 inferior calls

2019-12-21T10:12:17+00:00

echo -e '#include \nint main(void){\nsync();return 0;}'|./bin/clang -g -x c -;./bin/lldb -o 'file ./a.out' -o 'b main' -o r -o 'p (void)sync()' Actual: error: Expression can't be run, because there is no JIT compiled function Expected: This patch has been checked by: D71707: clang-tidy: new bugprone-pointer-cast-widening https://reviews.llvm.org/D71707 Casting from 32-bit `void *` to `uint64_t` requires an intermediate `uintptr_t` cast otherwise the pointer gets sign-extended: echo -e '#include \n#include \nint main(void){void *p=(void *)0x80000000;unsigned long long ull=(unsigned long long)p;unsigned long long ull2=(unsigned long long)(uintptr_t)p;printf("p=%p ull=0x%llx ull2=0x%llx\\n",p,ull,ull2);return 0;}'|gcc -Wall -m32 -x c -;./a.out : In function ‘main’: :3:66: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] p=0x80000000 ull=0xffffffff80000000 ull2=0x80000000 With debug output: Actual: IRMemoryMap::WriteMemory (0xb6ff8640, 0xffffffffb6f82158, 0x112) went to [0xb6ff8640..0xb6ff86b3) Code can be run in the target. Found function, has local address 0xffffffffb6f84000 and remote address 0xffffffffffffffff Couldn't disassemble function : Couldn't find code range for function _Z12$__lldb_exprPv Sections: [0xb6f84000+0x3c]->0xb6ff9020 (alignment 4, section ID 0, name .text) ... HandleCommand, command did not succeed error: Expression can't be run, because there is no JIT compiled function Expected: IRMemoryMap::WriteMemory (0xb6ff8640, 0xb6faa15c, 0x128) went to [0xb6ff8640..0xb6ff86c3) IRExecutionUnit::GetRemoteAddressForLocal() found 0xb6fac000 in [0xb6fac000..0xb6fac040], and returned 0xb6ff9020 from [0xb6ff9020..0xb6ff9060]. Code can be run in the target. Found function, has local address 0xb6fac000 and remote address 0xb6ff9020 Function's code range is [0xb6ff9020+0x40] ... Function data has contents: 0xb6ff9020: 10 4c 2d e9 08 b0 8d e2 08 d0 4d e2 00 40 a0 e1 ... Function disassembly: 0xb6ff9020: 0xe92d4c10 push {r4, r10, r11, lr} Differential revision: https://reviews.llvm.org/D71498

[lldb/DWARF] Switch to llvm location list parser

2019-12-09T12:39:10+00:00

Summary: This patch deletes the lldb location list parser and teaches the DWARFExpression class to use the parser in llvm instead. I have centralized all the places doing the parsing into a single GetLocationExpression function. In theory the the actual location list parsing should be covered by llvm tests, and this glue code by our existing location list tests, but since we don't have that many location list tests, I've tried to extend the coverage a bit by adding some explicit dwarf5 loclist handling and a test of the dumping code. For DWARF4 location lists this should be NFC (modulo small differences in error handling which should only show up on invalid inputs). In case of DWARF5, this fixes various missing bits of functionality, most notably, the lack of support for DW_LLE_offset_pair. Reviewers: JDevlieghere, aprantl, clayborg Subscribers: lldb-commits, dblaikie Tags: #lldb Differential Revision: https://reviews.llvm.org/D71003

[lldb] Improve/fix base address selection in location lists

2019-12-09T12:39:08+00:00

Summary: Lldb support base address selection entries in location lists was broken for a long time. This wasn't noticed until llvm started producing these kinds of entries more frequently with r374600. In r374769, I made a quick patch which added sufficient support for them to get the test suite to pass. However, I did not fully understand how this code operates, and so the fix was not complete. Specifically, what was lacking was the ability to handle modules which were not loaded at their preferred load address (for instance, due to ASLR). Now that I better understand how this code works, I've come to the conclusion that the current setup does not provide enough information to correctly process these entries. In the current setup the location lists were parameterized by two addresses: - the distance of the function start from the start of the compile unit. The purpose of this was to make the location ranges relative to the start of the function. - the actual address where the function was loaded at. With this the function-start-relative ranges can be translated to actual memory locations. The reason for the two values, instead of just one (the load bias) is (I think) MachO, where the debug info in the object files will appear to be relative to the address zero, but the actual code it refers to can be moved and reordered by the linker. This means that the location lists need to be "linked" to reflect the locations in the actual linked file. These two bits of information were enough to correctly process location lists which do not contain base address selection entries (and so all entries are relative to the CU base). However, they don't work with them because, in theory two base address can be completely unrelated (as can happen for instace with hot/cold function splitting, where the linker can reorder the two pars arbitrarily). To fix that, I split the first parameter into two: - the compile unit base address - the function start address, as is known in the object file The new algorithm becomes: - the location lists are processed as they were meant to be processed. The CU base address is used as the initial base address value. Base address selection entries can set a new base. - the difference between the "file" and "load" function start addresses is used to compute the load bias. This value is added to the final ranges to get the actual memory location. This algorithm is correct for non-MachO debug info, as there the location lists correctly describe the code in the final executable, and the dynamic linker can just move the entire module, not pieces of it. It will also be correct for MachO if the static linker preserves relative positions of the various parts of the location lists -- I don't know whether it actually does that, but judging by the lack of base address selection support in dsymutil and lldb, this isn't something that has come up in the past. I add a test case which simulates the ASLR scenario and demonstrates that base address selection entries now work correctly here. Reviewers: JDevlieghere, aprantl, clayborg Subscribers: dblaikie, lldb-commits Tags: #lldb Differential Revision: https://reviews.llvm.org/D70532