arm improvements/refactoring #13665
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arm improvements/refactoring #13665
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This matches how other archs do it, such as x86.
The analop_esil/analop64_esil functions have to wrap braces around the ESIL expression if there's a condition code. Instead of only printing the closing brace on certain instructions (which may differ from arm_prefix_cond one day), print it regardless of the instruction.
The cleaned up code fixes the following issues: 1. "bx pc" should always change to ARM mode (bits=32), never Thumb mode (bits=16), since PC is always even. 2. Use (addr & ~3LL) + pcdelta for all PC-relative arithmetic. and removes checks for "b reg"/"bl reg"/"bx imm"/"bxj imm" as these instructions don't exist.
Two changes: 1. Add signature for old gcc (4.6) that uses ldr/str instead of push/pop. 2. Mask out the Thumb bit from main's vaddr.
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Edit: Actually, the patch is correct because I only mask out the Thumb bit on the PC-relative branches (since PC is always even, even when you are in Thumb mode, according to my testing, which is why BX PC always brings you to ARM mode). I didn't change anything for the other types of branches. |
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Can you add some tests for those kind of binaries? Thanks for the pr!!
… On 8 Apr 2019, at 19:48, daddesio ***@***.***> wrote:
Actually, patch #3 ("Cleanup br instruction") is wrong. In the emulator, we shouldn't be masking out the Thumb bit from PC because that will prevent the emulator from staying in Thumb mode.
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My goal was to add a new glibc signature (so "s main" would work), and I ended up fixing other issues as well.
gcc-linaro-arm-linux-gnueabi-2012.01-20120125_linux (GCC 4.6.3, glibc 2.13) produces binaries with the following entry point that require the new signature: